Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel.
Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)
Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.
Stable oxygen atoms that have the same atomic number as the element oxygen, but differ in atomic weight. O-17 and 18 are stable oxygen isotopes.
Stable nitrogen atoms that have the same atomic number as the element nitrogen, but differ in atomic weight. N-15 is a stable nitrogen isotope.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
A hydrocarbon used as an industrial solvent. It has been used as an aerosal propellent, as a refrigerant and as a local anesthetic. (From Martindale, The Extra Pharmacopoeia, 31st ed, p1403)
The gaseous envelope surrounding a planet or similar body. (From Random House Unabridged Dictionary, 2d ed)
Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.
A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)
Separation of a mixture in successive stages, each stage removing from the mixture some proportion of one of the substances, for example by differential solubility in water-solvent mixtures. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Toxic, chlorinated, saturated hydrocarbons. Include both the 1,1- and 1,2-dichloro isomers. The latter is considerably more toxic. It has a sweet taste, ethereal odor and has been used as a fumigant and intoxicant among sniffers. Has many household and industrial uses.
The study of early forms of life through fossil remains.
A genus of gram-negative, aerobic, rod-shaped bacteria found in wet soil containing decaying organic material and in water. Cells tend to be pleomorphic if grown on media containing succinate or coccoid if grown in the presence of an alcohol as the sole carbon source. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A plant species of the genus PINUS which is the subject of genetic study.
The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)
A family of bacteria found in the mouth and intestinal and respiratory tracts of man and other animals as well as in the human female urogenital tract. Its organisms are also found in soil and on cereal grains.
The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)
Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. (From Merck Index, 11th ed)
Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)
Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)
The cycle by which the element carbon is exchanged between organic matter and the earth's physical environment.
Nanometer-sized tubes composed mainly of CARBON. Such nanotubes are used as probes for high-resolution structural and chemical imaging of biomolecules with ATOMIC FORCE MICROSCOPY.
Inorganic compounds that contain carbon as an integral part of the molecule but are not derived from hydrocarbons.
The 17-alpha isomer of TESTOSTERONE, derived from PREGNENOLONE via the delta5-steroid pathway, and via 5-androstene-3-beta,17-alpha-diol. Epitestosterone acts as an antiandrogen in various target tissues. The ratio between testosterone/epitestosterone is used to monitor anabolic drug abuse.
The loss of water vapor by plants to the atmosphere. It occurs mainly from the leaves through pores (stomata) whose primary function is gas exchange. The water is replaced by a continuous column of water moving upwards from the roots within the xylem vessels. (Concise Dictionary of Biology, 1990)
A plant genus of the family ASTERACEAE that is used for experiments in molecular genetic studies in plant physiology and development.
A plant genus of the family RHAMNACEAE. Several species have been reclassified to the FRANGULA genus. It is often called buckthorn but should not be confused with other plants called that.
A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
Total mass of all the organisms of a given type and/or in a given area. (From Concise Dictionary of Biology, 1990) It includes the yield of vegetative mass produced from any given crop.
The period of history before 500 of the common era.
A plant genus of the family MYRTACEAE. Members contain PHYTOHEMAGGLUTININS.
A genus of rod-shaped, oval, or bean-shaped bacteria found in soil and fresh water. Polar prosthecae are present and cells reproduce by budding at the tips of the prosthecae. Cells of this genus are aerobic and grow best with one-carbon compounds. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
Illegitimate use of substances for a desired effect in competitive sports. It includes humans and animals.
The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.
Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.
An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
A great expanse of continuous bodies of salt water which together cover more than 70 percent of the earth's surface. Seas may be partially or entirely enclosed by land, and are smaller than the five oceans (Atlantic, Pacific, Indian, Arctic, and Antarctic).
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Stable zinc atoms that have the same atomic number as the element zinc, but differ in atomic weight. Zn-66-68, and 70 are stable zinc isotopes.
A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
Closable openings in the epidermis of plants on the underside of leaves. They allow the exchange of gases between the internal tissues of the plant and the outside atmosphere.
An enzyme with high affinity for carbon dioxide. It catalyzes irreversibly the formation of oxaloacetate from phosphoenolpyruvate and carbon dioxide. This fixation of carbon dioxide in several bacteria and some plants is the first step in the biosynthesis of glucose. EC 4.1.1.31.
The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.
Water particles that fall from the ATMOSPHERE.
Stable sulfur atoms that have the same atomic number as the element sulfur, but differ in atomic weight. S-33, 34, and 36 are stable sulfur isotopes.
The ceasing of existence of a species or taxonomic groups of organisms.
Water containing no significant amounts of salts, such as water from RIVERS and LAKES.
A carboxy-lyase that plays a key role in photosynthetic carbon assimilation in the CALVIN-BENSON CYCLE by catalyzing the formation of 3-phosphoglycerate from ribulose 1,5-biphosphate and CARBON DIOXIDE. It can also utilize OXYGEN as a substrate to catalyze the synthesis of 2-phosphoglycolate and 3-phosphoglycerate in a process referred to as photorespiration.
Toxic asphyxiation due to the displacement of oxygen from oxyhemoglobin by carbon monoxide.
Deuterium. The stable isotope of hydrogen. It has one neutron and one proton in the nucleus.
A large family of narrow-leaved herbaceous grasses of the order Cyperales, subclass Commelinidae, class Liliopsida (monocotyledons). Food grains (EDIBLE GRAIN) come from members of this family. RHINITIS, ALLERGIC, SEASONAL can be induced by POLLEN of many of the grasses.
The dimension of the physical universe which, at a given place, orders the sequence of events. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Woody, usually tall, perennial higher plants (Angiosperms, Gymnosperms, and some Pterophyta) having usually a main stem and numerous branches.
Stable iron atoms that have the same atomic number as the element iron, but differ in atomic weight. Fe-54, 57, and 58 are stable iron isotopes.
Order of mammals whose members are adapted for flight. It includes bats, flying foxes, and fruit bats.
The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.
Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.
Inorganic salts of sulfuric acid.
The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)
Stable strontium atoms that have the same atomic number as the element strontium, but differ in the atomic weight. Sr-84, 86, 87, and 88 are the stable strontium isotopes.
A solvent for oils, fats, lacquers, varnishes, rubber waxes, and resins, and a starting material in the manufacturing of organic compounds. Poisoning by inhalation, ingestion or skin absorption is possible and may be fatal. (Merck Index, 11th ed)
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Any of several processes for the permanent or long-term artificial or natural capture or removal and storage of carbon dioxide and other forms of carbon, through biological, chemical or physical processes, in a manner that prevents it from being released into the atmosphere.
Method for assessing flow through a system by injection of a known quantity of radionuclide into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
A colorless, flammable, poisonous liquid, CS2. It is used as a solvent, and is a counterirritant and has local anesthetic properties but is not used as such. It is highly toxic with pronounced CNS, hematologic, and dermatologic effects.
Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Regular course of eating and drinking adopted by a person or animal.
Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.
The relationships of groups of organisms as reflected by their genetic makeup.
The rate dynamics in chemical or physical systems.
Methods for assessing flow through a system by injection of a known quantity of an indicator, such as a dye, radionuclide, or chilled liquid, into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
A measure of the total greenhouse gas emissions produced by an individual, organization, event, or product. It is measured in units of equivalent kilograms of CARBON DIOXIDE generated in a given time frame.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Stable mercury atoms that have the same atomic number as the element mercury, but differ in atomic weight. Hg-196, 198-201, and 204 are stable mercury isotopes.
The isotopic compound of hydrogen of mass 2 (deuterium) with oxygen. (From Grant & Hackh's Chemical Dictionary, 5th ed) It is used to study mechanisms and rates of chemical or nuclear reactions, as well as biological processes.
Creation and development of bodies within solar systems, includes study of early planetary geology.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
Isotopes that exhibit radioactivity and undergo radioactive decay. (From Grant & Hackh's Chemical Dictionary, 5th ed & McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Any solid objects moving in interplanetary space that are smaller than a planet or asteroid but larger than a molecule. Meteorites are any meteoroid that has fallen to a planetary surface. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The inanimate matter of Earth, the structures and properties of this matter, and the processes that affect it.
A dark powdery deposit of unburned fuel residues, composed mainly of amorphous CARBON and some HYDROCARBONS, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smoke. It is the product of incomplete combustion of carbon-rich organic fuels in low oxygen conditions. It is sometimes called lampblack or carbon black and is used in INK, in rubber tires, and to prepare CARBON NANOTUBES.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
Chromatographic techniques in which the mobile phase is a liquid.

An examination of coaxial stacking of helical stems in a pseudoknot motif: the gene 32 messenger RNA pseudoknot of bacteriophage T2. (1/7271)

The RNA pseudoknot located at the 5' end of the gene 32 messenger RNA of bacteriophage T2 contains two A-form helical stems connected by two loops, in an H-type pseudoknot topology. A combination of multidimensional NMR methods and isotope labeling were used to investigate the pseudoknot structure, resulting in a more detailed structural model than provided by earlier homonuclear NMR studies. Of particular significance, the interface between the stacked helical stems within the pseudoknot motif is described in detail. The two stems are stacked in a coaxial manner, with an approximately 18 degrees rotation of stem1 relative to stem2 about an axis that is parallel to the helical axis. This rotation serves to relieve what would otherwise be a relatively close phosphate-phosphate contact at the junction of the two stems, while preserving the stabilizing effects of base stacking. The ability of the NMR data to determine pseudoknot bending was critically assessed. The data were found to be a modestly precise indicator of pseudoknot bending, with the angle between the helical axes of stem1 and stem2 being in the range of 15+/-15 degrees. Pseudoknot models with bend angles within this range are equally consistent with the data, since they differ by only small amounts in the relatively short-range interproton distances from which the structure was derived. The gene 32 messenger RNA pseudoknot was compared with other RNA structures with coaxial or near-coaxial stacked helical stems.  (+info)

Prior protein intake may affect phenylalanine kinetics measured in healthy adult volunteers consuming 1 g protein. kg-1. d-1. (2/7271)

Study of the amino acid metabolism of vulnerable groups, such as pregnant women, children and patients, is needed. Our existing protocol is preceded by 2 d of adaptation to a low 13C formula diet at a protein intake of 1 g. kg-1. d-1 to minimize variations in breath 13CO2 enrichment and protein metabolism. To expand on our potential study populations, a less invasive protocol needs to be developed. We have already established that a stable background 13CO2 enrichment can be achieved on the study day without prior adaptation to the low 13C formula. Therefore, this study investigates phenylalanine kinetics in response to variations in prior protein intake. Healthy adult subjects were each fed nutritionally adequate mixed diets containing 0.8, 1.4 and 2.0 g protein. kg-1. d-1 for 2 d. On d 3, subjects consumed an amino acid-based formula diet containing the equivalent of 1 g protein. kg-1. d-1 hourly for 10 h and primed hourly oral doses of L-[1-13C]phenylalanine for the final 6 h. Phenylalanine kinetics were calculated from plasma-free phenylalanine enrichment and breath 13CO2 excretion. A significant quadratic response of prior protein intake on phenylalanine flux (P = 0.012) and oxidation (P = 0.009) was identified, such that both variables were lower following adaptation to a protein intake of 1.4 g. kg-1. d-1. We conclude that variations in protein intake, between 0.8 and 2.0 g. kg-1. d-1, prior to the study day may affect amino acid kinetics and; therefore, it is prudent to continue to control protein intake prior to an amino acid kinetics study.  (+info)

Carbon 13 NMR study of nonenzymatic reactions of pyridoxal 5'-phosphate with selected amino acids and of related reactions. (3/7271)

Carbon 13 nuclear magnetic resonance spectroscopy has been used to monitor the nonenzymatic reactions of pyridoxal 5'-phosphate with glycine, alanine, valine, serine, and with several other model compounds. Isotopically enriched amino acids were employed so that low concentrations could be utilized while still allowing relatively rapid acquisition of spectral data. The results for alanine and serine are particularly noteworthy in that alanine is deaminated to pyruvate and pyruvate is aminated to alanine, but contrary to the enzymatic reactions of various serine dehydratases wherein serine is converted to pyruvate, the nonenzymatic reaction utilizing serine results in hydroxypruvate rather than pyruvate formation. In the reverse reaction, hydroxypyruvate is aminated to serine but very inefficiently relative to the amination of pyruvate to alanine. The experimental results have been formulated into a proposed reaction mechanism for deamination of amino acids by pyridoxal-P.  (+info)

The Ice Man's diet as reflected by the stable nitrogen and carbon isotopic composition of his hair. (4/7271)

Establishing the diets of ancient human populations is an integral component of most archaeological studies. Stable isotope analysis of well-preserved bone collagen is the most direct approach for a general assessment of paleodiet. However, this method has been limited by the scarcity of well-preserved skeletal materials for this type of destructive analysis. Hair is preserved in many burials, but is often overlooked as an alternative material for isotopic analysis. Here we report that the stable carbon and nitrogen isotope values for the hair of the 5200 year-old Ice Man indicates a primarily vegetarian diet, in agreement with his dental wear pattern. Whereas previous investigations have focused on bone collagen, the stable isotope composition of hair may prove to be a more reliable proxy for paleodiet reconstruction, particularly when skeletal remains are not well preserved and additional archaeological artifacts are unavailable.  (+info)

European interlaboratory comparison of breath 13CO2 analysis. (5/7271)

The BIOMED I programme Stable Isotopes in Gastroenterology and Nutrition (SIGN) has focused upon evaluation and standardisation of stable isotope breath tests using 13C labelled substrates. The programme dealt with comparison of 13C substrates, test meals, test conditions, analysis techniques, and calculation procedures. Analytical techniques applied for 13CO2 analysis were evaluated by taking an inventory of instrumentation, calibration protocols, and analysis procedures. Two ring tests were initiated measuring 13C abundances of carbonate materials. Evaluating the data it was found that seven different models of isotope ratio mass spectrometers (IRMS) were used by the participants applying both the dual inlet system and the continuous flow configuration. Eight different brands of certified 13C reference materials were used with a 13C abundance varying from delta 13CPDB -37.2 to +2.0/1000. CO2 was liberated from certified material by three techniques and different working standards were used varying from -47.4 to +0.4/1000 in their delta 13CPDB value. The standard deviations (SDs) found for all measurements by all participants were 0.25/1000 and 0.50/1000 for two carbonates used in the ring tests. The individual variation for the single participants varied from 0.02 /1000 (dual inlet system) to 0.14/1000 (continuous flow system). The measurement of the difference between two carbonates showed a SD of 0.33/1000 calculated for all participants. Internal precision of IRMS as indicated by the specifications of the different instrument suppliers is < 0.3/1000 for continuous flow systems. In this respect it can be concluded that all participants are working well within the instrument specifications even including sample preparation. Increased overall interlaboratory variation is therefore likely to be due to non-instrumental conditions. It is possible that consistent differences in sample handling leading to isotope fractionation are the causes for interlaboratory variation. Breath analysis does not require sample preparation. As such, interlaboratory variation will be less than observed for the carbonate samples and within the range indicated as internal precision for continuous flow instruments. From this it is concluded that pure analytical interlaboratory variation is acceptable despite the many differences in instrumentation and analytical protocols. Coordinated metabolic studies appear possible, in which different European laboratories perform 13CO2 analysis. Evaluation of compatibility of the analytical systems remains advisable, however.  (+info)

Enzymatic synthesis of natural and 13C enriched linear poly-N-acetyllactosamines as ligands for galectin-1. (6/7271)

As part of a study of protein-carbohydrate interactions, linear N-acetyl-polyllactosamines [Galbeta1,4GlcNAcbeta1,3]nwere synthesized at the 10-100 micromol scale using enzymatic methods. The methods described also provided specifically [1-13C]-galactose-labeled tetra- and hexasaccharides ([1-13C]-Galbeta1,4GlcNAcbeta1,3Galbeta1,4Glc and Galbeta1, 4GlcNAcbeta1,3[1-13C]Galbeta1,4GlcNAcbeta1,3Galbeta 1,4Glc) suitable for NMR studies. Two series of oligosaccharides were produced, with either glucose or N-acetlyglucosamine at the reducing end. In both cases, large amounts of starting primer were available from human milk oligosaccharides (trisaccharide primer GlcNAcbeta1,3Galbeta1, 4Glc) or via transglycosylation from N-acetyllactosamine. Partially purified and immobilized glycosyltransferases, such as bovine milk beta1,4 galactosyltransferase and human serum beta1,3 N- acetylglucosaminyltransferase, were used for the synthesis. All the oligo-saccharide products were characterized by1H and13C NMR spectroscopy and MALDI-TOF mass spectrometry. The target molecules were then used to study their interactions with recombinant galectin-1, and initial1H NMR spectroscopic results are presented to illustrate this approach. These results indicate that, for oligomers containing up to eight sugars, the principal interaction of the binding site of galectin-1 is with the terminal N-acetyllactosamine residues.  (+info)

Documenting the diet in ancient human populations through stable isotope analysis of hair. (7/7271)

Fundamental to the understanding of human history is the ability to make interpretations based on artefacts and other remains which are used to gather information about an ancient population. Sequestered in the organic matrices of these remains can be information, for example, concerning incidence of disease, genetic defects and diet. Stable isotopic compositions, especially those made on isolates of collagen from bones, have been used to help suggest principal dietary components. A significant problem in the use of collagen is its long-term stability, and the possibility of isotopic alteration during early diagenesis, or through contaminating condensation reactions. In this study, we suggest that a commonly overlooked material, human hair, may represent an ideal material to be used in addressing human diets of ancient civilizations. Through the analysis of the amino-acid composition of modern hair, as well as samples that were subjected to radiation (thus simulating ageing of the hair) and hair from humans that is up to 5200 years old, we have observed little in the way of chemical change. The principal amino acids observed in all of these samples are essentially identical in relative abundances and content. Dominating the compositions are serine, glutamic acid, threonine, glycine and leucine, respectively accounting for approximately 15%, 17%, 10%, 8% and 8% of the total hydrolysable amino acids. Even minor components (for example, alanine, valine, isoleucine) show similar constancy between the samples of different ages. This constancy clearly indicates minimal alteration of the amino-acid composition of the hair. Further, it would indicate that hair is well preserved and is amenable to isotopic analysis as a tool for distinguishing sources of nutrition. Based on this observation, we have isotopically characterized modern individuals for whom the diet has been documented. Both stable nitrogen and carbon isotope compositions were assessed, and together provide an indication of trophic status, and principal type (C3 or C4) of vegetation consumed. True vegans have nitrogen isotope compositions of about 7/1000 whereas humans consuming larger amounts of meat, eggs, or milk are more enriched in the heavy nitrogen isotope. We have also analysed large cross-sections of modern humans from North America and Europe to provide an indication of the variability seen in a population (the supermarket diet). There is a wide diversity in both carbon and nitrogen isotope values based at least partially on the levels of seafood, corn-fed beef and grains in the diets. Following analysis of the ancient hair, we have observed similar trends in certain ancient populations. For example, the Coptics of Egypt (1000 BP) and Chinchorro of Chile (5000-800 BP) have diets of similar diversity to those observed in the modern group but were isotopically influenced by local nutritional sources. In other ancient hair (Egyptian Late Middle Kingdom mummies, ca. 4000 BP), we have observed a much more uniform isotopic signature, indicating a more constant diet. We have also recognized a primary vegetarian component in the diet of the Neolithic Ice Man of the Oetztaler Alps (5200 BP). In certain cases, it appears that sulphur isotopes may help to further constrain dietary interpretations, owing to the good preservation and sulphur content of hair. It appears that analysis of the often-overlooked hair in archaeological sites may represent a significant new approach for understanding ancient human communities.  (+info)

NMR studies on the 46-kDa dimeric protein, 3,4-dihydroxy-2-butanone 4-phosphate synthase, using 2H, 13C, and 15N-labelling. (8/7271)

3,4-Dihydroxy-2-butanone 4-phosphate synthase catalyses the release of C-4 from the substrate, ribulose phosphate, via a complex series of rearrangement reactions. The cognate ribB gene of Escherichia coli was hyperexpressed in a recombinant E. coli strain. The protein was shown to be a 46-kDa homodimer by hydrodynamic analysis. A variety of protein samples labelled with different grades of 13C, 15N and 2H, i.e. one with 100% 2H and 15N, one with 75% 2H, 99% 13C, 15N, and one with 100% 2H, 99% 13C,15N were prepared. Despite the large molecular size, 2- and 3-dimensional NMR spectra of reasonable quality were obtained. Attempts at the assignment of individual 13C, 15N and 1H signals show, in principle, the feasibility of structure determination. The number of NMR signals shows unequivocally that the homodimeric protein obeys strict C2 symmetry.  (+info)

C4 grasses form the foundation of warm-climate grasslands and savannas and provide important food crops such as corn, but their Neogene rise to dominance is still not fully understood. Carbon isotope ratios of tooth enamel, soil carbonate, carbonate cements, and plant lipids indicate a late Miocene-Pliocene (8-2 Ma) transition from C3 vegetation to dominantly C4 grasses at many sites around the world. However, these isotopic proxies cannot identify whether the C4 grasses replaced woody vegetation (trees and shrubs) or C3 grasses. Here we propose a method for reconstructing the carbon isotope ratio of Neogene grasses using the carbon isotope ratio of organic matter trapped in plant silica bodies (phytoliths). Although a wide range of plants produce phytoliths, we hypothesize that in grass-dominated ecosystems the majority of phytoliths will be derived from grasses, and will yield a grass carbon isotope signature. Phytolith extracts can be contaminated by non-phytolith silica (e.g., volcanic ash). ...
Read Stable carbon isotope ratio in xylotrophic fungi and their substrates, Russian Journal of Ecology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Abstract. A method for the determination of the stable carbon isotopic composition of atmospheric nitrophenols in the gas and particulate phases is presented. It has been proposed to use the combination of concentration and isotope ratio measurements of precursor and product to test the applicability of results of laboratory studies to the atmosphere. Nitrophenols are suspected to be secondary products formed specifically from the photooxidation of volatile organic compounds. XAD-4TM resin was used as an adsorbent on quartz filters to sample ambient phenols using conventional high volume air samplers at York University in Toronto, Canada. Filters were extracted in acetonitrile, with a HPLC (high-performance liquid chromatography) clean-up step and a solid phase extraction step prior to derivatization with BSTFA (bis(trimethylsilyl) trifluoroacetamide). Concentration measurements were done with gas chromatography-mass spectrometry and gas chromatography-isotope ratio mass spectrometry was used ...
The chlorofluorocarbons CFC-11 (CFCl3) and CFC-12 (CF2Cl2) are stable atmospheric compounds that are produced at the earths surface, but removed only at high altitudes in the stratosphere by photolytic reactions. Their removal liberates atomic chlorine that then catalytically destroys stratospheric ozone. For such long-lived compounds, isotope effects in the stratospheric removal reactions have a large effect on their global isotope budgets. We have demonstrated a photolytic isotope fractionation for stable carbon isotopes of CFC-11 and CFC-12 in laboratory experiments using broadband UV-C (190-230 nm) light. 13C/12C isotope fractionations (e) range from (-23.8±0.9) to (-17.7±0.4) ‰ for CFC-11 and (-66.2±3.1) to (-51.0±2.9) \permil for CFC-12 between 203 and 288 K, a temperature range relevant to conditions in the troposphere and stratosphere. These results suggest that CFCs should become strongly enriched in 13C with decreasing mixing ratio in the stratosphere, similar to what has been ...
In the last year, the stable isotope ratio analysis has become a useful tool with many applications in different scientific area. In particular the characteristic isotope signature of materials has permitted to identify authenticity and traceability of food sample and isotope composition has become a valuable marker in environmental studies. This work shows the applicability of analytical methods for isotopic carbon determination in food and environmental samples and the innovative use of δ13C in cultural heritage as valuable tool to trace pollutant fate. The first part is dedicated to the improvement of spectroscopic methods as Fourier Transform Infrared (FT-IR) and Non-Dispersive Infrared spectroscopy (NDIRS) and their application to identify geographical origin in sample like pasta, cocoa, olive oil. The results conducted in order to assess the robustness of the two alternative methods respecting IRMS showed a strong correlation like a demonstration of the positive relationship between the ...
Lakes are a source of methane, an important greenhouse gas in the atmosphere. In order to understand increasing methane emissions in the present, it is important to study the variations of methane release during past periods of climate change. However, records of methane release from lakes over time scales longer ... read more than a few years are extremely rare. In this thesis a method is explored to reconstruct past methane availability in lakes based on the stable carbon isotope composition (delta 13C) of aquatic invertebrate remains. Methane-derived 13C-depleted carbon can be an alternative carbon source to plant-derived material for invertebrates in the sediment and water column of lakes, that can lead to markedly depleted delta 13C values in invertebrate tissues. Using culturing experiments, it was demonstrated that methane-derived carbon is incorporated into chironomid head capsules. Also, it was shown that chemical pre-treatments that are commonly used for sediment processing do not have ...
RATIONALE: Recent advances in stable isotope probing (SIP) have allowed direct linkage of microbial population structure and function. This paper details a new development of SIP, Stable Isotope Switching (SIS), which allows the simultaneous assessment of carbon (C) uptake, turnover and decay, and the elucidation of soil food webs within complex soils or sedimentary matrices. METHODS: SIS utilises a stable isotope labelling approach whereby the 13C-labelled substrate is switched part way through the incubation to a natural abundance substrate. A 13CH4 SIS study of landfill cover soils from Odcombe (Somerset, UK) was conducted. Carbon assimilation and dissimilation processes were monitored through bulk elemental analysis isotope ratio mass spectrometry and compound-specific gas chromatography/combustion/isotope ratio mass spectrometry, targeting a wide range of biomolecular components including: lipids, proteins and carbohydrates. RESULTS: Carbon assimilation by primary consumers (methanotrophs) ...
is a valuable tracer for studying the processes controlling the autotrophic (FRa) and heterotrophic (FRh) contributions to ecosystem respiration (FR) and the influence of photosynthesis on FR. There is increasing interest in quantifying the temporal variability of the carbon isotope composition of ecosystem respiration (δR) because it contains information about the sources contributing to respiration and is an important parameter used for partitioning net ecosystem CO2 exchange using stable isotope methods. In this study, eddy covariance, flux gradient, automated chambers, and stable carbon isotope techniques were used to quantify and improve our understanding of the temporal variability in FR and δR in a C3/C4agricultural ecosystem. Six years (2004-2009) of isotope flux-gradient measurements indicated that δR had a very consistent annual pattern during both C3 (soybean) and C4(corn) growing seasons due to significant contributions from FRa, which was strongly influenced by the isotope ...
The data presented here comprise Ryazanian-Valanginian carbon isotope ratios analyzed from fossil wood and belemnites from the shallow marine Boyarka River succession in Siberia. Additional belemnite carbon isotope ratios from the Izhma River succession (also Ryazanian-Valanginian) in Russia are also presented. The wood-derived and belemnite-derived isotope ratios are considered to primarily reflect changes in the terrestrial and marine carbon isotope reservoirs respectively. The δ13Ccarb and δ13Cwood records reveal a distinct mid-Valanginian positive carbon isotope excursion, with the initiation occurring near the Boreal Russian michalskii-polyptychus zone boundary, which is broadly time-equivalent Tethyan campylotoxus-verrucosum boundary. The Ryazanian-Valanginian δ13Ccarb values fluctuate between c. −1 and +1.5‰ but reach a maximum of +4.1‰ in the Late Valanginian, whilst the δ13Cwood values fluctuate between c. −27 and −23.5‰ and reach a Late Valanginian maximum of ...
Semantic Scholar extracted view of Forensic Examination of Australian Papers Using Isotope Ratio Mass Spectrometry by Kylie Jones et al.
Compound-specific carbon and hydrogen isotope ratios are routinely measured on extractable organic matter to decipher biogeochemical processes and events in Earth history. To deliver accurate interpretations, it is paramount that isotopic values are derived from indigenous compounds and are not the result of contamination. However, distinguishing between compounds from these different provenances can be difficult, especially if a degree of mixing occurred. In this study, we assess the impact of hydrocarbon contamination on the carbon and hydrogen isotopic composition of n-alkanes from similar to 820 Ma Precambrian evaporitic drill core samples through exterior/interior (E/I) rock extraction experiments. In these experiments, exterior and interior portions of the same rock samples were separately crushed to powder, extracted and processed. Compound-specific isotope values of n-alkanes from the different rock portions were subsequently measured and compared. In most cases, n-alkanes from exterior ...
Background:You are what you eat is an accurate summary for humans and animals when it comes to carbon isotope abundance. In biological material, natural13C/12C ratio is subject to minute variations due to diet composition (mainly from ingestion of C3 and C4 metabolism plants) and to the discrimination between light and heavy isotopes during biochemical reactions (isotope effects and isotopic fractionation).Methodology/Principal Findings:Carbon isotopic abundance was measured in ZDF (fa/+) and ZDF (fa/fa), (lean and obese-diabetic rats respectively) fed the same diet. By analysing plasma metabolites (glucose and non-esterified fatty acids), breath and liver tissue by high-precision isotope ratio mass spectrometry, we demonstrate for the first time statistically distinguishable metabolic carbon isotope abundance between ZDF (fa/+) and ZDF (fa/fa) rats based on plasma glucose, palmitic, oleic, linoleic, arachidonic acids and bulk analysis of liver tissue (P|0.005) resulting into clear isotopic
Yu ZQ,Sheng GY,Piu JM,et al. Determination of porphyrin carbon isotopic composition using gas chromatography-isotope ratio monitoring mass spectrometry[J]. Journal of Chromatography A,2000,903(1-2):183-191 ...
Oxygen and carbon isotope ratios were measured for hydrothermal minerals (silica, clay and calcite) from fractures and vugs in altered rhyolite, located between 28 and 129 m below surface (in situ temperatures ranging from 81 to 199??C) in Yellowstone drill holes. The purpose of this study was to investigate the mechanism of formation of these minerals. The ??18O values of the thirty-two analyzed silica samples (quartz, chalcedony, ??-cristobalite, and ??-cristobalite) range from -7.5 to +2.8???. About one third of the silica 7samples have ??18O values that are consistent with isotopic equilibrium with present thermal waters; most of the other silica samples appear to have precipitated from water enriched in 18O (up to 4.7???) relative to present thermal water, assuming precipitation at present in situ temperatures. Available data on fluid-inclusion homogenization temperatures in hydrothermal quartz indicate that silica precipitation occurred mostly at temperatures above those measured during drilling
Freeman, Katherine H., Mueller, Kevin E., Diefendorf, Aaron F., Wing, Scott L., and Koch, Paul L. 2011. Clarifying the influence of water availability and plant types on carbon isotope discrimination by C3 plants. Proceedings of the National Academy of Sciences of the United States of America. 108 (16):E59-E60. https://doi.org/10.1073/pnas.1102556108 ...
The concept of metabolic compartmentation describes the presence in a tissue of functionally different and chemically distinct pools of a given substrate. These separate pools equilibrate only very slowlyt if at a11, and exhibit different turnover and flux rates. Such heterogeneous functional pools of amino acids were coming under investigation in microorganisms (Britten et al. 1955; Cowie, Walton 1956; Cowie, McClure 1959), plants (Steward et al. 1956; Maclennan et al. 1963), and animal tissues (Korner, Tarver 1957; Green, Lowther 1959; Kipnis et al. 1961) at about the same time that we began our studies on glutamate-glutamine metabolism in brain. The first reference to the term metabolic compartmentstion trat we have noted is in the work of Stuart et al. (1956). In their studies on the carrot root explant, they found that glutamic acid derived from [U-l4C]glutamine had a higher specific activity (counts/min/μmol, SA) than the glutamine isolated from the tissue, a situation opposite to that which
The 2nd Annual USADA Symposium on Anti-Doping Science was to discuss the use of GC-C-IRMS in the identification of exogenous substances entering the native metabolic pool.
Thomas Whelan, Harry H. Roberts; Carbon isotope composition of diagenetic carbonate nodules from freshwater swamp sediments. Journal of Sedimentary Research ; 43 (1): 54-58. doi: https://doi.org/10.1306/74D726DF-2B21-11D7-8648000102C1865D. Download citation file:. ...
If you have a question about this talk, please contact Julia Montes-Landa.. Abstract not available. This talk is part of the Pitt-Rivers Archaeological Science Seminar Series series.. ...
Background/Question/Methods. The partitioning of net ecosystem exchange of CO2 (NEE) measured via the eddy covariance technique into gross photosynthesis (GPP) and ecosystem respiration (Reco) can be challenging and is often associated with unknown amounts of uncertainty. In order to estimate GPP from NEE, typically nighttime measurements of Reco are extrapolated to the day using a temperature function. Then Reco is subtracted from NEE to obtain GPP (i.e., GPP = NEE - Reco). However, recent evidence employing stable carbon isotopes of CO2 has shown that this practice can strongly overestimate GPP and Reco, from 10-100%. This is due to reduced leaf respiration during the day, aka the Kok effect. One key parameter for partitioning NEE using stable carbon isotopes is the isotopic composition of carbon respiration by the ecosystem, δ13Cr. δ13Cr is typically estimated using a Keeling plot with nighttime data either sampled via a profile method or single-inlet sampling where measurements are ...
The stable carbon isotopic analysis of tree-rings for environmental, plant physiological and archaeological applications using conventional methods is occasionally limited by physical constraints (narrow rings) or administrative concerns (requirement for non-destructive sampling) that prevent researcher access to scientifically valuable wood samples. Analysis of such archives by laser-ablation can potentially address these issues and facilitate access to restricted archives. Smaller quantities of wood are required for analysis by laser ablation, hence the approach may be considered less-invasive and is virtually non-destructive compared to standard preparation methods. High levels of intra-annual isotopic variability reported elsewhere mean that a single measurement may not faithfully represent the inter-annual isotopic signal, so before such an approach can be used with confidence it is necessary to compare the stable carbon isotopic data produced using these two methods. This paper presents ...
Hoins, M. , Eberlein, T. , Van de Waal, D. B. , Sluijs, A. , Reichart, G. J. and Rost, B. (2016): CO2-dependent carbon isotope fractionation in dinoflagellates relates to their inorganic carbon fluxes , Journal of Experimental Marine Biology and Ecology ...
Steude, J. S., C.P. Sullivan, R. C. Chaney, M. McKee, L. E. OShea. 1990. Tracer Experiments in Saturated Sand by Computed Tomography and Inductively Coupled Plasma, Physico-Chemical Aspects of Soil and Related Materials, ASTM STP 1095, K. B. Hoddinott and R.O. Lamb, Eds., American Society for Testing and Materials, Philadelphia, 1990, pp. 171-184.. ...
Los Gatos Research is developing a simple robust methodology for the determination of carbon isotope ratios in small gas samples. This new measurement scheme is inherently compact and rugged and offers a great potential for adaptation into space vehicles. With such a sensitive method of accurately determining carbon isotope levels we hope to significantly advance the prospects for making in-situ tests for evidence of life on nearby planets, such as Mars. The isotope ratio is known to be a sensitive indicator of biologic activity. The new innovative advancement we propose to make will make such measurements potentially much easier than currently possible. We will demonstrate the new absorption analysis technique at wavelengths of 1.5 microns in Phase I and demonstrate that the approach can be used to record the relative isotopic abundance of carbon 12 and 13 with great accuracy ...
The ratio of 13C to 12C in marine sedimentary rocks holds important clues to the evolution of the carbon cycle through Earth history. Isotopic analyses are traditionally carried out using isotope ratio mass spectrometry (IRMS), but this technique is labor-intensive, expensive and requires expert know-how. He
TY - JOUR. T1 - Land use driven change in soil pH affects microbial carbon cycling processes. AU - Malik, Ashish A.. AU - Puissant, Jeremy. AU - Buckeridge, Kate M.. AU - Goodall, Tim. AU - Jehmlich, Nico. AU - Chowdhury, Somak. AU - Gweon, Hyun Soon. AU - Peyton, Jodey M.. AU - Mason, Kelly E.. AU - van Agtmaal, Maaike. AU - Blaud, Aimeric. AU - Clark, Ian M.. AU - Whitaker, Jeanette. AU - Pywell, Richard F.. AU - Ostle, Nick. AU - Gleixner, Gerd. AU - Griffiths, Robert I.. N1 - A.A.M. has received funding from the European Unions Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant no. 655240 and all other UK-based authors were funded by the UK Natural Environment Research Council under a Soil Security Programme grant (NE/M017125/1). We also acknowledge Kathleen Eismann for her help in sample preparation for metaproteomic analysis; Heiko Moossen, Petra Linke and Steffen Ruehlow for assistance with stable carbon isotope analyses and all the land owners who ...
ABSTRACT: In freshwater food webs, a substantial contribution of methane-derived carbon for the nutrition of larvae of the macroinvertebrate species Chironomus plumosus has been proposed from stable carbon isotope analysis. We investigated if the larvae feed on methanogenic Archaea or methane-oxidising bacteria (MOB), and whether the carbon transfer is based on digestion of the microbial biomass or on a symbiotic relationship. Fluorescence in situ hybridisation (FISH) with larval tissue thin sections showed that the larvae are not inhabited by methanogens or MOB as symbionts or part of their tissue and gut microflora. Furthermore, clone libraries for the bacterial 16S rRNA gene from larval tissue and comparative denaturing gradient gel electrophoresis (DGGE) of sediment and larval DNA samples showed that the eubacterial community present in the larval gut is dominated by anaerobic and facultatively anaerobic bacteria, whereas MOB were only rarely found. Additionally, comparative quantitative PCR ...
D7026-13 Standard Guide for Sampling and Reporting of Results for Determination of Biobased Content of Materials via Carbon Isotope Analysis carbon content~ carbon isotope analysis~
Abstract Mud gas data represent the first breath of a well being drilled. However, despite significant progress in technology, techniques and theoretical understanding of mud gas detection and analysis, such data are still largely under-utilized b
A survey of Mesozoic organic-rich shales in space and time indicates that they are widely distributed through much of the era but are concentrated especially at two levels: Upper Jurassic (Kimmeridgian-Volgian/Tithonian) and Middle Cretaceous (Aptian-Turonian). Stable carbon isotope studies prove to be a particularly useful tool in both palaeoenvironmental and diagenetic analysis. Anoxic events in the ocean may be characterized by high concentrations of δ13 carbonate carbon. The carbon isotope values obtained may, however, reflect diagenesis in the sulphate reduction zone rather than conditions in the original sea water. Calcite concretions formed at successive stages in diagenesis may record a change from strongly negative to strongly positive values of δ13C, indicating a switch from the sulphate-reduction to the fermentation zone.. Analysis of benthic palaeoecology leads to a classification of marine mudrocks into barren laminite, shelly laminite, shelly shale and shelly mudstone, of which ...
Potter KE, Ono S, Prinn RG. 2013. Fully automated, high-precision instrumentation for the isotopic analysis of tropospheric N2O using continuous flow isotope ratio mass spectrometry.. Rapid communications in mass spectrometry : RCMRapid communications in mass spectrometry : RCM. 27(15):1723-38. ...
Deep continental subsurface fracture water systems, ranging from 1.1 to 3.3 km below land surface (kmbls), were investigated to characterize the indigenous microorganisms and elucidate microbial carbon sources and their cycling. Analysis of phospholipid fatty acid (PLFA) abundances and direct cell counts detected varying biomass that was not correlated with depth. Compound-specific carbon isotope analyses (δ13C and Δ14C) of the phospholipid fatty acids (PLFAs) and carbon substrates combined with genomic analyses did identify, however, distinct carbon sources and cycles between the two depth ranges studied.. In the shallower boreholes at circa 1 kmbls, isotopic evidence indicated microbial incorporation of biogenic CH4 by the in situ microbial community. At the shallowest site, 1.05 kmbls in Driefontein mine, this process clearly dominated the isotopic signal. At slightly deeper depths, 1.34 kmbls in Beatrix mine, the isotopic data indicated the incorporation of both biogenic CH4 and dissolved ...
Deep continental subsurface fracture water systems, ranging from 1.1 to 3.3 km below land surface (kmbls), were investigated to characterize the indigenous microorganisms and elucidate microbial carbon sources and their cycling. Analysis of phospholipid fatty acid (PLFA) abundances and direct cell counts detected varying biomass that was not correlated with depth. Compound-specific carbon isotope analyses (δ13C and Δ14C) of the phospholipid fatty acids (PLFAs) and carbon substrates combined with genomic analyses did identify, however, distinct carbon sources and cycles between the two depth ranges studied.. In the shallower boreholes at circa 1 kmbls, isotopic evidence indicated microbial incorporation of biogenic CH4 by the in situ microbial community. At the shallowest site, 1.05 kmbls in Driefontein mine, this process clearly dominated the isotopic signal. At slightly deeper depths, 1.34 kmbls in Beatrix mine, the isotopic data indicated the incorporation of both biogenic CH4 and dissolved ...
BACKGROUND: Improvement of water-use efficiency (WUE) can effectively reduce production losses caused by drought stress. A better understanding of the genetic determination of WUE in crops under drought stress has great potential value for developing cultivars adapted to arid regions. To identify the genetic loci associated with WUE and reveal genes responsible for the trait in apple, we aim to map the quantitative trait loci (QTLs) for carbon isotope composition, the proxy for WUE, applying two contrasting irrigating regimes over the two-year experiment and search for the candidate genes encompassed in the mapped QTLs. RESULTS: We constructed a high-density genetic linkage map with 10,172 markers of apple, using single nucleotide polymorphism (SNP) markers obtained through restriction site-associated DNA sequencing (RADseq) and a final segregating population of 350 seedlings from the cross of Honeycrisp and Qinguan. In total, 33 QTLs were identified for carbon isotope composition in apple under ...
Thermo Delta Plus Isotope Ratio Mass Spectrometer used extensively for the measurement of 2H/1H in water using a chromium reduction inlet. This magnetic sector instrument is optimized for hydrogen isotope ratio analysis of water samples between 0.2 and 1 g, although analysis of samples as small as 1 uL can be performed. The precision of the d2H measurement is 0.5 permil or 0.08 ppm.. Thermo Delta V Isotope Ratio Mass Spectrometer used extensively for the measurement of 13C/12C, 15N/14N, 18O/16O. The instrument is equipped with gas bench and elemental analyzer inlets. The gas bench is used for measurement of 13C/12C in carbon dioxide, and 18O/16O in water by equilibration with carbon dioxide. Specimen size for carbon dioxide is 0.05 mL (STP) and water is 1 g. Precisions are d13C = 0.1 permil (1 ppm) and d18O = 0.1 permil (0.06 ppm). The elemental analyzer is used for bulk sample analysis of 13C/12C and 15N/14N. Sample size is 0.5 mg of organic material. Precisions are d13C = 0.1 permil (1 ppm) ...
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Die Universität zu Köln ist eine Exzellenzuniversität mit dem klassischen Fächerspektrum einer Volluniversität. Als eine der größen Hochschulen Europas arbeitet sie in Forschung und Lehre auch international auf höchstem Niveau.
At the Curití Quarry, Eastern Cordillera of Colombia, a 23.35 m section includes a 6.3 m interval of organic-rich marlstones, calcareous clay-shales and clay-shales devoid of benthic fossils and bioturbation, at the base of the Paja Formation. It overlies carbonate ramp deposits of the Rosablanca Formation, with the topmost layer containing reworked and phosphatized assemblages of middle Barremian to lowest Aptian ammonites of the genera Pulchellia, Gerhardtia, Toxancycloceras, Karsteniceras and Prodeshayesites. High-resolution analyses of the section, including total inorganic carbon (TIC, 0.09-50 wt%), total organic carbon (TOC, up to 8.4%) and stable carbon isotope measurements (δ13Corg between −22.05‰ and −20.47‰) allow the determination of the stratigraphic relationship between the organic-rich level within the Paja Formation and Oceanic Anoxic Event-1a (OAE-1a). The range of values and the overall pattern of the δ13Corg curve are comparable with the Lower Aptian interval C7. ...
This series of activities is designed to introduce students to the role of sediments and sedimentary rocks in the global carbon cycle. Students learn how stable carbon isotopes can be used to reconstruct ancient sedimentary environments. Students will make some simple calculations, formulate hypotheses, and think about the implications of their results. The activity includes an optional demonstration of the density separation of a sediment sample into a light, organic fraction and a heavier, mineral fraction.. ...
This series of activities is designed to introduce students to the role of sediments and sedimentary rocks in the global carbon cycle. Students learn how stable carbon isotopes can be used to reconstruct ancient sedimentary environments. Students will make some simple calculations, formulate hypotheses, and think about the implications of their results. The activity includes an optional demonstration of the density separation of a sediment sample into a light, organic fraction and a heavier, mineral fraction.. ...
Deng J, McCalley CK, Frolking S, Chanton J, Crill P, Varner R, Tyson GW, Rich V, Hines M, Saleska SR et al.. 2017. Adding stable carbon isotopes improves model representation of the role of microbial communities in peatland methane cycling. Journal of Advances in Modeling Earth Systems. 9(2):1412-1430. ...
Oxygen and carbon isotopic compositions have been determined from the belemnite genera Acroteuthis and Hibolites sampled from the early Cretaceous (Ryazanian-Hauterivian) interval of the Speeton Clay Formation, Filey Bay, England. The Speeton Clay Formation consists of a series of claystones and calcareous mudrocks deposited in an epicontinental sea. delta(18)O values from belemnites, which met petrographic and chemical criteria for well preserved skeletal carbonate, indicate warm marine palaeotemperatures (c. 12-15 degrees C) for much of the early Valanginian whilst cool temperatures (,9 degrees C) are inferred for the earliest Hauterivian. During the remainder of the Hauterivian, temperatures fluctuated considerably and rose to a maximum of 15.5 degrees C. Changes in kaolinite and smectite abundances, considered to reflect humid and arid phases of climate, correlate with warm and cool episodes. The palaeotemperature record, appears to contradict evidence from cephalopod faunas, which show a ...
Use the nitrogen tree: Turn heat on high. Set pressure regulator on tank to 2-4 psi. Flow gauge should read 8 L/min for two samples. Clean capillary tips with ethanol, unscrew white plastic, move metal shaft down (may need to wipe with ethanol to allow this), insert capillary tip into glass sample vial (close to liquid but not touching), screw plastic threading back to lock the metal shaft in place. Leave heating block on. Move sample vial up hourly as liquid evaporates ...
Use the nitrogen tree: Turn heat on high. Set pressure regulator on tank to 2-4 psi. Flow gauge should read 8 L/min for two samples. Clean capillary tips with ethanol, unscrew white plastic, move metal shaft down (may need to wipe with ethanol to allow this), insert capillary tip into glass sample vial (close to liquid but not touching), screw plastic threading back to lock the metal shaft in place. Leave heating block on. Move sample vial up hourly as liquid evaporates ...
carbon isotope ratio: A measure of the proportion of the carbon-14 isotope to the carbon-12 isotope. Living material contains carbon-14 and carbon-12 in the same ...
A short-term simulated weathering experiment was performed on two crude oils and two heavy fuel oils under natural conditions to evaluate the effects of natural weathering processes by using gas chromatography mass spectrometry combined with gas chromatography isotopic ratio mass spectrometry. The results of diagnostic ratios of n-alkanes show that only odd to even predominance (OEP1, OPE2) and carbon preference index (CPI) remain stabilized during the 28 d weathering process, but they cannot effectively distinguish the four types of oils. Statistical analyses based on paired sample t-test and principal component analysis (PCA) revealed that stable carbon isotope compositions of n-alkanes in the four studied oils have no significant changes over the weathering time, and that the carbon isotope discrimination (Delta delta C-13) of n-alkanes is , 3 parts per thousand. We have provided evidence that the stable carbon isotope compositions of n-alkanes compared to n-alkanes diagnostic ratios ...
Helichrysum italicum (Roth) G. Don fil. subsp. italicum oils, coming from Sicily and Corsica and growing up, at equal geographical area, at the same edaphic and climatic conditions, were investigated by GC-MS, GC-FID and gas chromatography carbon isotope ratio mass spectrometry (GC-C-IRMS). GC-MS and GC-FID analyses on the oils terpene fraction have evidenced two different compositional finger prints (chemotypes). Investigating the carbon isotope ratio of the main and common terpene compounds, were also highlighted different plants genetic behaviors. The i-stds elaboration has permitted to investigate on the plants genetic changes, taking into account only the secondary biogenetic pathways, in which the terpenes formation occurs ...
We used stable carbon isotopes to analyse individual variation in arctic fox diet. We extracted collagen from bones (the lower jaw), and measured stable carbon isotopes. The foxes came from three different localities: Iceland, where both microtines and reindeer are rare; west Greenland, where microtines are absent; and Sweden, where seat analyses showed the primary food to be microtine rodents and reindeer. The Icelandic samples included foxes from both coastal and inland habitats, the Swedish sample came from an inland area, and the Greenland sample from coastal sites. The spatial variation in the isotopic pattern followed a basic division between marine and terrestrial sources of protein. Arctic foxes from inland sites had delta(13)C values of -21.4 (Ice land) and -20.4 parts per thousand (Sweden), showing typical terrestrial values. Coastal foxes from Greenland had typical marine Values of -14.9 parts per thousand, whereas coastal foxes from Iceland had intermediate values of -17.7 parts per ...
The increasing number of bomb attacks involving improvised explosive devices, as well as the nature of the explosives, give rise to concern among safety and law enforcement agencies. The substances used in explosive charges are often everyday products diverted from their primary licit applications. Thus, reducing or limiting their accessibility for prevention purposes is difficult. Ammonium nitrate, employed in agriculture as a fertiliser, is used worldwide in small and large homemade bombs. Black powder, dedicated to hunting and shooting sports, is used illegally as a filling in pipe bombs causing extensive damage. If the main developments of instrumental techniques in explosive analysis have been constantly pushing the limits of detection, their actual contribution to the investigation of explosives in terms of source discrimination is limited. Forensic science has seen the emergence of a new technology, isotope ratio mass spectrometry (IRMS), that shows promising results. Its very f
Stable carbon isotope analyses of the humin fraction of the soil organic matter were conducted on more than 160 soil profiles from Tikal, Guatemala. The profiles were collected from near areas associated with the earthworks of Tikal; an ancient ditch and parapet construction hypothesized to have formed ancient boundaries of the polity. In addition to the isotope analyses, the physical and chemical characteristics of the horizons were determined. Maize, a C4 plant, formed an integral part of the ancient Maya diet and is the only known C4 plant cultivated by the Maya. Prior to and subsequent to the ancient Maya occupation of Tikal, the landscape was dominated by C3 forest vegetation. Over the centuries C4 plant biomass including rhizodeposition decomposed to form soil organic matter that contains a distinct C4 signature reflecting the vegetation history of the area. Forested areas anciently cleared for agriculture were identified through interpretation of significant isotopic shifts that signaled past
Arı́stegui J, Duarte CM, Agustı́ S, Doval M, Álvarez-Salgado XA, Hansell DA. 2002. Dissolved organic carbon support of respiration in the dark ocean. Science. 298(5600):1967-1967. doi:10.1126/science.1076746.. Boyd PW, Sherry ND, Berges JA, Bishop JKB, Calvert SE, Charette MA, Giovannoni SJ, Goldblatt R, Harrison PJ, Moran SB, et al. 1999. Transformations of biogenic particulates from the pelagic to the deep ocean realm. Deep Sea Res, Part II. 46(11):2761-2792. doi:10.1016/S0967-0645(99)00083-1.. Carter JF, Barwick VJ, editors. 2011. Good practice guide for isotope ratio mass spectrometry. 1st edition. Bristol: FIRMS.. Cavan EL, Trimmer M, Shelley F, Sanders R. 2017. Remineralization of particulate organic carbon in an ocean oxygen minimum zone. Nat Commun. 8(1):1-9. doi:10.1038/ncomms14847.. Cifuentes LA, Sharp JH, Fogel ML. 1988. Stable carbon and nitrogen isotope biogeochemistry in the Delaware estuary: Carbon and nitrogen isotopes. Limnol Oceanogr. 33(5):1102-1115. ...
The major source of carbon to the bacterial community in a seagrass (Thalassia testudinum) dominated region of Lower Laguna Madre, Texas was determined with the isotopic composition of bacterial phospholipid fatty acids. Rough estimates of bacterial abundance were also obtained from total phospholipid fatty acid concentrations. Core samples came from three differing habitat types consisting of a bare area, a transitional area, and a vegetated area. Five depth intervals of 0-0.5 cm, 0.5-2.5 cm, 4.5-6.5 cm, 8.5-10.5 cm, and 18.5-20.5 cm from each core were used for analyses. Bacterial abundance was significantly higher in the vegetated habitat compared with bare or transitional habitats, which showed little difference from one another. The stable carbon isotope ratios ([ð]¹³C) of branched chain fatty acids, iso- and anteiso-15:0 (i&a15:0) found only in bacteria were used to assess carbon utilization. The [ð]¹³C of total organic carbon (TO¹³C) and the ubiquitous fatty acid 16:0 were used as ...
Carbon isotope effects were investigated for the reaction catalyzed by the glycine decarboxylase complex (GDC; EC 2.1.2.10). Mitochondria isolated from leaves of pea (Pisum sativum L.) and spinach (Spinacia oleracea L.) were incubated with glycine, and the CO2 evolved was analyzed for the carbon isotope ratio (delta C-13). Within the range of parameters tested (temperature, pH, combination of cofactors NAD(+), ADP, pyridoxal 5-phosphate), carbon isotope shifts of CO2 relative to the C-1-carboxyl carbon of glycine varied from +14 parts per thousand to -7 parts per thousand. The maximum effect of cofactors was observed for NAD(+), the removal of which resulted in a strong C-12 enrichment of the CO2 evolved. This indicates the possibility of isotope effects with both positive and negative signs in the GDC reaction. The measurement of delta C-13 in the leaves of the GDC-deficient barley ( Hordeum vulgare L.) mutant (LaPr 87/30) plants indicated that photorespiratory carbon isotope fractionation, ...
We investigated the relationships between foliar stable carbon isotope discrimination (Delta), % foliar N, and predawn water potentials ((water potential symbol)pd) and midday stomatal conductance (g(s)) of Larrea tridentata across five Mojave Desert soils with different age-specific surface and sub-surface horizon development and soil hydrologies. We wished to elucidate how this long-lived evergreen shrub optimizes leaf-level physiological performance across soils with physicochemical characteristics that affect the distribution of limiting water and nitrogen resources. We found that in young, coarse alluvial soils that permit water infiltration to deeper soil horizons, % foliar N was highest and Delta, g(s) and psgrpd were lowest, while %N was lowest and Delta, g(s) and (water potential symbol)pd were highest in fine sandy soils; Larrea growing in older soils with well-developed surface and sub-surface horizons exhibited intermediate values for these parameters. Delta showed negative linear
Across a wide range of environmental conditions, forest types and tree species we found carbon isotope ratios of wood to be a strong and reliable indicator of past drought occurrence (Fig. 2a). However, despite this clear physiological signal of drought on δ13C, we only found a weak and context-dependent effect of these same drought events on tree growth (Fig. 2b). Previous studies have suggested that the relationship between carbon isotopes and growth might not be a simple one (Ferrio et al. 2003; Peñuelas et al. 2008; Jansen et al. 2013; Hentschel et al. 2016; Shestakova et al. 2017), but to our knowledge none had explored the relationship across a broad enough range of species and environmental conditions to draw this conclusion robustly. The relatively small declines in growth we observed in response to drought suggest that most European tree species are - on average - able to maintain growth under conditions of low soil water availability.. This is not to say that water availability is ...
TY - JOUR. T1 - Measurement of δ18O and δ2H values of fluid inclusion water in speleothems using cavity ring-down spectroscopy compared with isotope ratio mass spectrometry. AU - Arienzo, Monica M.. AU - Swart, Peter K.. AU - Vonhof, Hubert B.. N1 - Copyright: Copyright 2013 Elsevier B.V., All rights reserved.. PY - 2013/12/15. Y1 - 2013/12/15. N2 - RATIONALE The hydrogen and oxygen isotopic analyses (δ2H and δ18O values) of water trapped within speleothem carbonate (fluid inclusions) have traditionally been conducted utilizing dual-inlet isotope ratio mass spectrometry (IRMS) or continuous-flow (CF)-IRMS methods. The application of cavity ring-down spectroscopy (CRDS) to the δ2H and δ18O analysis of water in fluid inclusions has been investigated at the University of Miami as an alternative method to CF-IRMS. METHODS An extraction line was developed to recover water from the fluid inclusions consisting of a crusher, sample injection port and an expansion volume (either 100 or 50 cm3) ...
Enamel stable carbon isotope analyses were conducted on the large fossil ape Gigantopithecus blacki and an associated mammalian megafauna from Longgudong Cave in Jianshi and Juyuandong Cave in Liuchen
NUCLEAR MAGNETIC RESONANCE IMAGING + NUCLEAR MAGNETIC RESONANCE TOMOGRAPHY (MEDICAL DIAGNOSTICS); NMR-MIKROSKOPIE, NMR-ABBILDUNDSVERFAHREN; CARBON-13 NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; NUTRITION + NUTRITIONAL SCIENCE; BONE MARROW (CYTOLOGY, HISTOLOGY); KNOCHENMARK (CYTOLOGIE, HISTOLOGIE); ERNÄHRUNG + ERNÄHRUNGSWISSENSCHAFT; FETTSÄUREN (BIOCHEMIE); FATTY ACIDS (BIOCHEMISTRY); MUSKELZELLEN (CYTOLOGIE, HISTOLOGIE); KOHLENSTOFF-13-KERNRESONANZSPEKTROSKOPIE; KERNSPINRESONANZ-ABBILDUNGSVERFAHREN + KERNSPINRESONANZ-TOMOGRAPHIE (MEDIZINISCHE DIAGNOSTIK); MUSCLE CELLS (CYTOLOGY, HISTOLOGY); NMR MICROSCOPY, NMR ...
TY - GEN. T1 - Carbon isotope signatures and their possible link to upwelling, Middle Mississippian crinoidal-bryozoan carbonates, Illinois Basin. AU - Lasemi, Z.. N1 - hand-typed from author-received information. PY - 2018. Y1 - 2018. KW - ISGS. M3 - Conference contribution. SP - 88. BT - Book of Abstracts. CY - Quebec City, Canada. ER - ...
0057] The presence of 14C, the content of biomaterial, the content of biocarbon or the content of organic carbon of renewable origin of a material is determined on the basis of standards ASTM D 6866 (ASTM D 6866-06) and ASTM D 7026 (ASTM D 7026-04). Standard ASTM D 6866 relates to Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis, whereas standard ASTM D 7026 relates to Sampling and Reporting of Results for Determination of Biobased Content of Materials via Carbon Isotope Analysis. The second standard refers in its first paragraph to the first standard. The first standard describes a test for measuring the 14C/12C ratio of a sample and compares it with the 14C/12C ratio of a reference sample of 100% renewable origin, to give a relative percentage of C of renewable origin in the sample. The standard is based on the same concepts as 14C dating, but without applying dating equations. The ratio thus calculated is designated ...
Scheele, N. and Hoefs, J. (1992): Carbon isotope fractionation between calcite, graphite and CO2 an experimental study , Contrib Mineral Petrol ...
We present new carbon and oxygen isotope curves from sections in the Bakony Mts. (Hungary), constrained by biostratigraphy and magnetostratigraphy in order to evaluate whether carbon isotopes can provide a tool to help establish and correlate the last system boundary remaining undefined in the Phanerozoic as well provide data to better understand the carbon cycle history and environmental drivers during the Jurassic-Cretaceous interval. We observe a gentle decrease in carbon isotope values through the Late Jurassic. A pronounced shift to more positive carbon isotope values does not occur until the Valanginian, corresponding to the Weissert event. In order to place the newly obtained stable isotope data into a global context, we compiled 31 published and stratigraphically constrained carbon isotope records from the Pacific, Tethyan, Atlantic, and Boreal realms, to produce a new global δ13C stack for the Late Oxfordian through Early Hauterivian interval. Our new data from Hungary is consistent ...
Diverse interpretations have been made of carbon isotope time series in speleothems, reflecting multiple potential controls. Here we study the dynamics of 13C and 12C cycling in a particularly well-constrained site to improve our understanding of processes affecting speleothem δ13C values. The small, tubular Grotta di Ernesto cave (NE Italy) hosts annually-laminated speleothem archives of climatic and environmental changes. Temperature, air pressure, pCO2, dissolved inorganic carbon (DIC) and their C isotopic compositions were monitored for up to five years in soil water and gas, cave dripwater and cave air. Mass-balance models were constructed for CO2 concentrations and tested against the carbon isotope data. Air advection forces winter pCO2 to drop in the cave air to ca. 500 ppm from a summer peak of ca. 1500 ppm, with a rate of air exchange between cave and free atmosphere of approximately 0.4 days. The process of cave ventilation forces degassing of CO2 from the dripwater, prior to any ...
The Waikato Stable Isotope Unit (WSIU) offers precision analyses of isotopes of carbon and nitrogen in biological, geological, and chemical materials by isotope ratio mass spectrometry. Isotopic abundance analysis is carried out on two fully automated Europa Scientific 20/20 isotope analysers. Materials may be submitted as solids, liquids, or gases, for example, for breath analyses. Precision analyses of carbon and nitrogen content in solid or liquid samples are also provided with a LECO TruSpec Carbon/Nitrogen Determinator fitted with an autosampler for liquids.. The WSIU provides commercial analyses and also services the needs of scientists at the University of Waikato and their collaborators, promoting the use of stable isotopes in all branches of research. Staff are highly experienced in the use of stable isotopes, both natural abundance and enriched tracers, particularly in biological and environmental research. In 2006 the WSIU was accredited by the International Atomic Energy Agency for ...
Fossils of many species are common all the way across the landscape, Ambrose said. But this species is missing in action from the east side of the distribution.. Isotopic analysis of teeth found on the site gave a more complete picture of the habitat of the animals that lived and died there, Ambrose said.. The distribution of plant carbon isotope ratios conveniently separates out grasslands from forests, he said. And it also separates out grazing animals, like zebras, from browsing animals that eat the leaves off of trees, like giraffes.. The distribution of the fossil browsers and grazers echoed that of the habitat, he said.. On the west we find lots of Ardipithecus fossils and theyre associated with a lot of woodland and forest animals, he said. And then theres a break; Ardipithecus and most of the monkeys that live in trees disappear, and grass-eating animals become more abundant.. The carbon isotope ratios of the Ardipithecus teeth also tell the story of a woodland creature, he ...
Håkon Mosby Mud Volcano (HMMV, SW Barents Sea slope, 1280 m) is one of the numerous cold methane-venting seeps existing along the continental margins. Analyses of videoguided core samples revealed extreme differences in the diversity and density of the metazoan meiobenthic communities associated with the different sub-habitats (centre, microbial mats, Pogonophora field, outer rim) of this mud volcano. Diversity was lowest in the sulphidic, microbial mat sediments that supported the highest standing stock, with unusually high densities (11 000 ind. 10 cm-2) of 1 nematode species related to Geomonhystera disjuncta. Stable carbon isotope analyses revealed that this nematode species was thriving on chemosynthetically derived food sources in these sediments. Ovoviviparous reproduction has been identified as an important adaptation of parents securing the survival and development of their brood in this toxic environment. The proliferation of this single species in exclusive association with ...
We measure stable isotope ratios of carbon and nitrogen in organic matrix using conventional isotope ratio mass spectrometers. For a price offer, please contact the corresponding network partner. Animal tissue: --, Dr. Christian C. Voigt at: [email protected] Plant material: --, Dr. Zachary Kayler at: [email protected] Historic samples --, Dr. Ulrich Struck at: [email protected] ...
The Chrono Centre undergo Isotope Ratio Mass Spectrometry (EA-IRMS) using a Thermo Delta V Advantage IRMS machine and accompanying Flash 112 elemental analyser.
This publication was developed by an international group of experts as an integral part of the IAEAs efforts to contribute to the transfer of technology and knowledge in nutrition. Its aim is to assist Member States in their efforts to combat malnutrition by facilitating the use of relevant nuclear techniques. The stable (non-radioactive) isotope technique has been developed to assess intake of human milk in breastfed infants. The practical application of the stable isotope technique, based on analysis of deuterium by Fourier transform infrared spectrometry (FTIR), is presented in this book.. ...
All 3795 co-registered samples were analyzed for their soluble major anion content (Cl-, NO3-, SO42-) by ion chromatography (IC) and for trace elements (Na, Mg, Ca, Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Al, S, Ti, V, Cr, Mn, Fe, Co, Cu, Zn) by inductively coupled plasma sector field mass spectrometry (ICP-MS). Major anions were analyzed on a Dionex DX-500 ion chromatograph coupled to a Gilson autosampler, and concentrations are reported in ug/L (ppb). Trace elements analyses were performed with the University of Maine Thermo Electron Element2 ICP-MS coupled to a Cetac Model ASX- 260 autosampler. Isotopes were measured in low and medium resolution (GIVE range ppt-ppq). The ICP-MS samples were acidified to 1% with double-distilled HN03 under a class-100 High Efficiency Particle Air (HEPA) clean bench and allowed to react with the acid for approximately 1 week before being frozen. Approximately every fifth sample (713 total) was analyzed for dD by isotope ratio mass spectrometry (IRMS) using a ...
As most of the uses of plants are intimately linked to their metabolic output or activity, there is a renewed interest in understanding the behavior and regulation of plant metabolic networks. The only direct measure of metabolic activity, and the facet most closely related to biological function, is flux through the metabolic network (Libourel and Shachar-Hill, 2008). There has been a considerable research effort in the last few years to develop and refine methods that allow fluxes in large metabolic networks to be determined. The best established of these methods, steady-state metabolic flux analysis (MFA), involves measuring the redistribution of a supplied stable isotope, usually 13C, at metabolic and isotopic steady state (Ratcliffe and Shachar-Hill, 2006; Allen et al., 2009a). Flux maps of a range of heterotrophic plant cells and tissues have been produced, providing information on the operation of different flux modes (Sriram et al., 2004, 2007; Schwender et al., 2006; Allen et al., ...
STICKSTOFFORGANISCHE UMWELTSCHADSTOFFE; ABBAU, ZERSETZUNG, UMWANDLUNG, PERSISTENZ VON UMWELTSCHADSTOFFEN (UMWELTPROBLEME); TRIAZIN-DERIVATE (PESTIZIDWIRKSTOFFE); REDUKTION (CHEMISCHE REAKTIONEN); PHOTOCHEMISCHE REAKTIONEN (CHEMISCHE REAKTIONEN); ISOTOPIEEFFEKT (CHEMISCHE KINETIK); STICKSTOFF-15-ISOTOP; NITROGEN ORGANIC ENVIRONMENTAL POLLUTANTS; DEGRADATION, DECOMPOSITION, TRANSFORMATION, PERSISTENCE OF POLLUTANTS (ENVIRONMENTAL PROBLEMS); TRIAZINE-DERIVATIVES (PESTICIDE AGENTS); REDUCTION (CHEMICAL REACTIONS); PHOTOCHEMICAL REACTIONS (CHEMICAL REACTIONS); ISOTOPE EFFECT (CHEMICAL KINETICS); NITROGEN-15- ...
The first one is the mineralogical and geochemical investigation of ore and non-ore deposits in Slovakia and elsewhere in the World. Traditional analytical methods (electron probe micro-analysis, X-ray diffraction) are employed to characterize raw and dump materials mineralogically, chemically and structurally. Apart from this, fluid inclusion microthermometry, isotope ratio mass spectrometry combined with thermodynamic modeling are employed to decipher age and formation conditions of raw materials. This approach was applied to genetic studies of polymetallic ore deposits of Central Slovakian volcanics, magnesite, siderite, barite and stibnite deposits in Ore Mountains of Slovakia, and a polymetallic ore deposit in Kosovo. Recently, we are studying genesis of a phosphate deposit in Mozambique ...
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We hypothesize that the rapid onset of the carbon isotope excursion (CIE) at the Paleocene/Eocene boundary (V55 Ma) may have resulted from the accretion of a significant amount of 12C-enriched carbon from the impact of a V10 km comet, an event that would also trigger greenhouse warming leading to the Paleocene/Eocene thermal maximum and, possibly, thermal dissociation of seafloor methane hydrate. Indirect evidence of an impact is the unusual abundance of magnetic nanoparticles in kaolinite-rich shelf sediments that closely coincide with the onset and nadir of the CIE at three drill sites on the Atlantic Coastal Plain. After considering various alternative mechanisms that could have produced the magnetic nanoparticle assemblage and by analogy with the reported detection of iron-rich nanophase material at the Cretaceous/Tertiary boundary, we suggest that the CIE occurrence was derived from an impact plume condensate. The sudden increase in kaolinite is thus thought to represent the redeposition on the
We are investigating how the carbon isotope composition of fossil land plants and fossil organic matter can be used to infer climate change in ancient ecosystems.. M.T. Rabanus-Wallace, M.J. Wooller, G.D. Zazula, E. Shute, A.H. Jahren, P. Kosintsev, J.A. Burns, J. Breen, B. Llamas and A. Cooper. 2017. Megafaunal isotopes reveal role of increased moisture on rangeland during Late Pleistocene extinctions. Nature Ecology & Evolution, 1, 0125, DOI: 10.1038/s41559-017-0215. (view/download pdf). B.A. Schubert% and A.H. Jahren. 2013. Reconciliation of marine and terrestrial carbon isotope excursions based on changing atmospheric CO2 levels. Nature Communications, 4:1653, DOI: 10.1038/ncomms2659. (view/download pdf). A.H. Jahren, B.A. Schubert%, L. Marynowski and J.P. Wilson*. The carbon isotope organic geochemistry of Early Ordovician rocks from the Annascaul Formation, County Kerry. Irish Journal of Earth Sciences, 31: 1-12; doi: 10.3318/IJES.2013.31. (view/download pdf).. G.J. Retallack and A.H. ...
We are investigating how the carbon isotope composition of fossil land plants and fossil organic matter can be used to infer climate change in ancient ecosystems.. M.T. Rabanus-Wallace, M.J. Wooller, G.D. Zazula, E. Shute, A.H. Jahren, P. Kosintsev, J.A. Burns, J. Breen, B. Llamas and A. Cooper. 2017. Megafaunal isotopes reveal role of increased moisture on rangeland during Late Pleistocene extinctions. Nature Ecology & Evolution, 1, 0125, DOI: 10.1038/s41559-017-0215. (view/download pdf). B.A. Schubert% and A.H. Jahren. 2013. Reconciliation of marine and terrestrial carbon isotope excursions based on changing atmospheric CO2 levels. Nature Communications, 4:1653, DOI: 10.1038/ncomms2659. (view/download pdf). A.H. Jahren, B.A. Schubert%, L. Marynowski and J.P. Wilson*. The carbon isotope organic geochemistry of Early Ordovician rocks from the Annascaul Formation, County Kerry. Irish Journal of Earth Sciences, 31: 1-12; doi: 10.3318/IJES.2013.31. (view/download pdf).. G.J. Retallack and A.H. ...
Abstract: We construct an interaction between a (2,0) tensor multiplet in six dimensions and a self-dual string. The interaction is a sum of a Nambu-Goto term, with the tension of the string given by the modulus of the scalar fields of the tensor multiplet, and a non-local Wess-Zumino term, that encodes the electromagnetic coupling of the string to the two-form gauge field of the tensor multiplet. The interaction is invariant under global (2,0) supersymmetry, modulo the equations of motion of a free tensor multiplet. It is also invariant under a local fermionic kappa-symmetry, as required by the BPS-property of the string ...
Natural-abundance 13C nuclear magnetic resonance spectra of ten common nucleotides in neutral, aqueous solutions have been determined and interpreted. The spectra of two of these substances were also determined in acidic solutions, and several of the carbon chemical shifts were found to depend markedly on pH. Within the limited range of concentrations employed, there were observed no carbon chemical-shift changes which could be ascribed to base-stacking or base-pairing phenomena. ...
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Heterogeneous and homogeneous processes in the formation of diamond at low pressures, where diamond is a metastable modification of carbon, are discussed. Data on the kinetics of the growth of diamond from hydrocarbons under conditions which give codeposition with graphite are reported, together with data on the influence of hydrogen on this process and on the resulting fractionation of the stable carbon isotopes. Chemical and plasma-chemical methods of preparing diamond and diamond-like layers are discussed, as well as methods based on the use of atomic and ionic beams. The most recent theoretical and experimental results on the homogeneous formation of diamond in the gas phase are presented ...
Researchers have achieved the first long temperature reconstruction for the eastern Mediterranean using the stable carbon isotopes found in tree rings found in the region.
Liu, Junwen,Mo, Yangzhi,Ding, Ping,Li, Jun,Shen, Chengde,&Zhang, Gan.(2018).Dual carbon isotopes (C-14 and C-13) and optical properties of WSOC and HULIS-C during winter in Guangzhou, China.SCIENCE OF THE TOTAL ENVIRONMENT,633,1571-1578 ...
Ordovician Carbon Isotope Curve By Bergstrom, S.M., Xu Chen, Gutierrez-Marco, J.C., and Dronov, A., 2008, Lethaia, DOI: 10.1111/j.1502-39 Click HERE t
ISOFLEX supplies stable and radioactive isotopes. With competitive pricing, certified isotopic enrichment, expedited processing and delivery and exemplary customer service, ISOFLEX is your premier isotope supplier. Contact us with your specific requirements.
TY - JOUR. T1 - Measurement of de novo hepatic lipogenesis in humans using stable isotopes. AU - Hellerstein, M. K.. AU - Christiansen, M.. AU - Kaempfer, S.. AU - Kletke, C.. AU - Wu, K.. AU - Reid, J. S.. AU - Mulligan, K.. AU - Hellerstein, N. S.. AU - Shackleton, C. H L. PY - 1991/5. Y1 - 1991/5. N2 - Direct measurement of de novo lipogenesis has not previously been possible in humans. We measured de novo hepatic lipogenesis in normal men by means of stable isotopes and by combining the acetylated-xenobiotic probe technique with mass isotopomer analysis of secreted very low density lipoprotein-fatty acids (VLDL-FA). Sulfamethoxazole (SMX) was administered with [13C]acetate during an overnight fast followed by refeeding with intravenous glucose (7-10 mg/kg of weight per min), oral Ensure (7-10 mg of carbohydrate/kg of weight per min), or a high-carbohydrate mixed-meal breakfast (3.5 g of carbohydrate/kg of weight). Respiratory quotients remained , 1.0. High-performance liquid ...
The STRI Soils Laboratory in Panama operates an Isotope Ratio Mass Spectrometer (IRMS) for the determination of stable isotopes of carbon, hydrogen, oxygen and nitrogen in environmental samples. A variety of samples can be analyzed, including soils, plant and animal tissue, geological samples, gases, and waters. We also operate a cavity ring-down spectrometer for high precision determination of δ18O and δ2H in liquids.. ...
^12C. ^13C, and ^14C. The heaviest isotope shown has a half life of about 6000 years (this is from memory, so check). The ^13C isotope is abundant enough (approx. 1%) to make ^13C NMR spectroscopy a routine method of characterization for organic chemists. Most universities would have 1 or more ^13C NMR spectrometers. ^12C isotope is the bog standard, naturally abundant one that you sprinkle on your cornflakes when it (the isotope) is bound to oxygen and hydrogen.
Scientists engaged in climate research, biochemistry, forensics and oilgas exploration can now analyze the isotopic anatomy of molecules using a new high-resolution isotope ratio mass spectrometer from Thermo Fisher Scientific . This new instrument will allow scientists to access the direct conditions under which molecules were formed,...
Scientists engaged in climate research, biochemistry, forensics and oilgas exploration can now analyze the isotopic anatomy of molecules using a new high-resolution isotope ratio mass spectrometer from Thermo Fisher Scientific . This new instrument will allow scientists to access the direct conditions under which molecules were formed,...
Because stable carbon isotope ratios of plant tissues change based on the inorganic carbon sources for photosynthesis, ... The storage of carbon is an essential ecosystem service as we move into a period of elevated atmospheric carbon levels. However ... O'Leary, Marion H. (1988). "Carbon Isotopes in Photosynthesis". BioScience. 38 (5): 328-336. doi:10.2307/1310735. JSTOR 1310735 ... These meadows account for more than 10% of the ocean's total carbon storage. Per hectare, it holds twice as much carbon dioxide ...
C3 plants preferentially use the lighter of two isotopes of carbon in the atmosphere, 12C, which is more readily involved in ... O'Leary, Marion (May 1988). "Carbon Isotopes in Photosynthesis". BioScience. 38 (5): 328-336. doi:10.2307/1310735. JSTOR ... but the carbon isotope record suggests that they were too scarce to impact the atmospheric composition until around 850 million ... being closer to C3 plants if they fix most carbon in the day and closer to C4 plants if they fix all their carbon at night. ...
The ratio of carbon-13 and carbon-12 isotopes in these types of plants is as follows: C4 plants: -16 to -10 ‰ CAM plants: -20 ... Carbon isotopes: you are what you eat Hair-rising research Ayacucho Archaeo Isotope Project The pursuit of isotopic and ... In addition, there are two types of plants with different biochemical pathways; the C3 carbon fixation, where the isotope ... Farquhar, G D; Ehleringer, J R; Hubick, K T (1989). "Carbon Isotope Discrimination and Photosynthesis". Annual Review of Plant ...
C3 plants preferentially use the lighter of two isotopes of carbon in the atmosphere, 12C, which is more readily involved in ... O'Leary, Marion (May 1988). "Carbon Isotopes in Photosynthesis". BioScience. 38 (5): 328-336. doi:10.2307/1310735. JSTOR ... being closer to C3 plants if they fix most carbon in the day and closer to C4 plants if they fix all their carbon at night. It ... The enzyme RuBisCO is responsible for "fixing" CO 2 - that is, it attaches it to a carbon-based molecule to form a sugar, which ...
ISBN 978-1-4443-3301-5. Mook, W. G., & Tan, F. C. (1991). Stable carbon isotopes in rivers and estuaries. Biogeochemistry of ... This signal is also a function of the amount of carbon burial; when organic carbon is buried, more 12C is locked out of the ... O'Leary, M. H. (1988). "Carbon Isotopes in Photosynthesis". BioScience. 38 (5): 328-336. doi:10.2307/1310735. JSTOR 1310735. ... Stable isotope forensics : methods and forensic applications of stable isotope analysis (Second ed.). Hoboken, NJ. ISBN 978-1- ...
... carbon, and oxygen isotopes that must be kept away from the atmosphere.[19] The 15N:14N ratio is commonly used in stable ... The heavy isotope 15N was first discovered by S. M. Naudé in 1929, soon after heavy isotopes of the neighbouring elements ... Nitrogen does not share the proclivity of carbon for catenation. Like carbon, nitrogen tends to form ionic or metallic ... Iso-tope Abun-dance Half-life (t1/2) Decay mode Pro-duct ... Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium ...
Isotopes. Main article: Isotopes of carbon. Isotopes of carbon are atomic nuclei that contain six protons plus a number of ... Carbon can form very long chains of interconnecting carbon-carbon bonds, a property that is called catenation. Carbon-carbon ... naturally occurring isotopes.[15] The isotope carbon-12 (12C) forms 98.93% of the carbon on Earth, while carbon-13 (13C) forms ... The paths of carbon in the environment form the carbon cycle. For example, photosynthetic plants draw carbon dioxide from the ...
Carbon isotopes indicate "dry woodland" conditions. This seeming contradiction between the seasonally dry climate and tropical ...
Klein, R.G. (2013). "Stable carbon isotopes and human evolution". PNAS. 110 (26): 10470-2. doi:10.1073/pnas.1307308110. PMC ... More direct stable isotope evidence from Neanderthal bodies also indicates a heavy, though by no means exclusive reliance on ... In February 2019, scientists reported evidence, based on isotope studies, that at least some Neanderthals may have eaten meat. ... This is corroborated by stable carbon isotopic evidence indicating the consumption of plants found along riversides and under ...
Carbon has three naturally occurring isotopes. About 99% of carbon on Earth is carbon-12 (12C), about 1% is carbon-13 (13C), ... doi:10.1016/0160-4120(79)90005-9. Farquhar, G. D.; Ehleringer, J. R.; Hubick, K. T. (1989). "Carbon Isotope Discrimination and ... is a change in the ratio of the atmospheric concentrations of heavy isotopes of carbon (13C and 14C) by the admixture of large ... and a trace amount is carbon-14 (14C). The 12C and 13C isotopes are stable, while 14C decays radioactively to nitrogen-14 (14N ...
Stable isotope analysis monitors the ratio of carbon 13 to carbon 12 (13C/12C), which is expressed as parts per mil (per ... Nitrogen isotopes in bone collagen are ultimately derived from dietary protein, while carbon can be contributed by protein, ... Stable isotope analysis of carbon and nitrogen in human bone collagen allows bioarchaeologists to carry out dietary ... Rounick, J.S.; Winterbourn, M.J. (1986). "Stable Isotopes and Carbon Flow in Ecosystems". BioScience. 36 (3): 171-77. doi: ...
... which prefers carbon-12 over carbon-13, resulting in carbon isotope fractionation in the rock record. Sedimentary rocks ... Stable Isotopes and Plant Carbon-Water Relations. Elsevier. 2012-12-02. ISBN 9780080918013. McCollom, Thomas M. (2013-01-01). " ... Isotope tracers can be used to track biochemical reactions to understand microbial metabolism. Isotope natural abundance in ... Stable isotopes of water are sometimes used as tracers of water sources and flow paths between the physical environment and the ...
... the three isotopes of carbon are known as carbon-12, carbon-13, and carbon-14, often abbreviated to 12C, 13C, and 14C. Carbon ... Thus, for example, there are three main isotopes of carbon. All carbon atoms have 6 protons in the nucleus, but they can have ... For example, all carbon atoms contain 6 protons in their atomic nucleus; so the atomic number of carbon is 6. Carbon atoms may ... Of the 80 elements with at least one stable isotope, 26 have only one single stable isotope. The mean number of stable isotopes ...
Karhu, J.A.; Holland, H.D. (1 October 1996). "Carbon isotopes and the rise of atmospheric oxygen". Geology. 24 (10): 867-870. ... The flow of carbon dioxide from the atmosphere to the soil is therefore regulated with the help of living beings. When CO2 ... Carbon precipitation, solution and fixation are influenced by the bacteria and plant roots in soils, where they improve gaseous ... Much of the falling dead shells, however, re-dissolve into the ocean below the carbon compensation depth. One of these ...
For example, carbon has two stable, naturally occurring isotopes: carbon-12 (6 neutrons) and carbon-13 (7 neutrons). Carbon-14 ... is a naturally occurring radioactive isotope of carbon. At least two isotopes of each element are known (except for Oganesson, ... Isotopes[change , change source]. Most elements in nature consist of atoms with different numbers of neutrons.[7] An isotope is ... For example, carbon has the chemical symbol 'C', and sodium has chemical symbol 'Na', after the Latin natrium. Tungsten is ...
Characterization of photobiont associations in lichens using carbon isotope discrimination techniques. Stable Isotopes and ... algal and cyanobacterial photobionts of lichen associations was also identified using gas exchange and carbon isotope isotopes ... In sea water for example, the pH is such that dissolved inorganic carbon (DIC) is mainly found in the form of HCO3−. The net ... From there on, the pyrenoid was studied in the wider context of carbon acquisition in algae, but has yet to be given a precise ...
She has done extensive work on the use of carbon isotopes for source apportionment of urban carbon dioxide fluxes. Diane ... Bowling, David R.; Pataki, Diane E.; Randerson, James T. (January 7, 2008). "Carbon isotopes in terrestrial ecosystem pools and ... 2003). Seasonal cycle of carbon dioxide and its isotopic composition in an urban atmosphere: anthropogenic and biogenic effects ... Macelwane Medal in 2008 from the American Geophysical Union for her research on coupled water and carbon cycles. The award is ...
Other more neutron-deficient and more unstable isotopes can be formed by the irradiation of platinum with carbon nuclei. ... Atterling, H.; Forsling, W. (1959). "Light Polonium Isotopes from Carbon Ion Bombardments of Platinum". Arkiv för Fysik. 15 (1 ... Polonium is a very rare element in nature because of the short half-lives of all its isotopes. Seven isotopes occur in traces ... Not specified is the isotope under study, but at the time polonium-210 was the most readily available polonium isotope. The DoE ...
Hayes made the first measurements of the distribution of the isotopes of carbon within biolipids. This innovation provided a ... Hayes, John M. (2001). "Fractionation of Carbon and Hydrogen Isotopes in Biosynthetic Processes". Reviews in Mineralogy and ... Hayes, John M; Waldbauer, Jacob R (2006). "The carbon cycle and associated redox processes through time". Philosophical ... Hayes's studies of the carbon cycle bear strongly on the development of the global environment and provide evidence about the ...
His work uses stable isotopes of carbon (carbon-13 and oxygen (Δ18O) to integrate carbon and hydrological cycles for individual ... Seibt, Ulli; Rajabi, Abazar; Griffiths, Howard; Berry, Joseph A. (2008). "Carbon isotopes and water use efficiency: sense and ... Measurements of gas exchange and of carbon isotope ratio and their ecological implications". Oecologia. 53 (1): 68-78. Bibcode: ... He has investigated carbon concentrating mechanisms (see photosynthesis) in algae and hornworts, focusing on the molecular ...
Petroleum is also studied via carbon isotope analysis. Carbon isotopes provide insight into the Earth's carbon cycle and ... Stahl W.J. (1979) Carbon Isotopes in Petroleum Geochemistry. In: Jäger E., Hunziker J.C. (eds) Lectures in Isotope Geology. ... Geochemists are able to discern the composition of petroleum deposits by examining the ratio of carbon isotopes and comparing ... Examination of the parent to daughter ratio of uranium isotopes has led to the dating of select samples to the Late Cretaceous ...
One is the U of A Stable Isotope Laboratory, which is able to analyze light isotopes of organics, carbonates, phosphates, and ... In 2016, she was awarded the Deep Carbon Observatory Diversity Grant by the American Geosciences Institute. In 2019, Suarez ... Suarez, C.A., You, H-L, Suarez, M.B., Li, D-Q, and Trieschmann, J.B. (2017) Stable isotopes reveal rapid enamel elongation ( ... Suarez, Celina A.; You, Hai-Lu; Suarez, Marina B.; Li, Da-Qing; Trieschmann, J. B. (2017-11-10). "Stable Isotopes Reveal Rapid ...
It was found as isotopes 14N, 15N, and 16N. Carbon and fixed nitrogen would be required for farming activities within a sealed ... Carbon on the Moon. Artemis Society International. 8 August 1999. "The chemistry of carbon in the lunar regolith." Colin Trevor ... Volatiles from permanently shadowed craters may provide methane (CH 4), ammonia (NH 3), carbon dioxide (CO 2) and carbon ... Carbon (C) would be required for the production of lunar steel, but it is present in lunar regolith in trace amounts (82 ppm), ...
Distribution of natural isotopes of carbon in Linsley Pond and other New England lakes. Limnol. Oceanogr. 9:1-11. 1964 With M. ... Fractionation of sulfur and carbon isotopes in a meromictic lake. Science 139:407-408. 1964 With M. Stuiver. ... Carbon 13 in lake waters, and its possible bearing on paleolimnology. Am. J. Sci. 258-A:253-72. 1963 With N. Nakai and M. ... He was a creative pioneer in several areas, including quantitative palynology, cycling of natural isotopes, biogeochemistry, ...
Carbon isotope ratios vary by plant type, and so a change in carbon ratio of an elephant can indicate a shift in diet from ... Using carbon isotope ratios in prehistoric human bone collagen, Fogel was able to study the diet of ancient humans. North ... Fogel has used carbon, nitrogen, and strontium isotope ratios to study African elephant diet and habitat use in the Amboseli ... Stable isotope ratios can also reveal diet specialization and shifts as specific carbon and nitrogen ratios are often ...
"A 400 million year carbon isotope record of pedogenic carbonate; implications for paleoatmospheric carbon dioxide" (PDF). ... Very high atmospheric concentrations of carbon dioxide in the Late Jurassic led to high temperatures around the globe, due to ...
... using carbon and oxygen isotopes to prove their biological origin". But it was Lowenstam's 1961 discovery of "biochemically- ... During this time, the University of Chicago had emerged as the birthplace of isotope geochemistry, and Harold Urey's research ... Caltech and the University of California began the building of their isotope geochemistry programs and their recruitment of ... group was making significant advancements in the use of deviations in stable isotopes to measure ancient ocean temperatures. ...
Casanova, Joel; Hillare-Marcel, Claude (1993). Carbon and Oxygen Isotopes in African Lacustrine Stromatolites: ...
In 1976, he began writing about oxygen and carbon isotopes. By 1980 he was involved in dating studies utilizing isotopes of ...
Even when compounds only contain elements with less intense isotope peaks (carbon or oxygen), the distribution of these peaks ... Isotope effects[edit]. Isotope peaks within a spectrum can help in structure elucidation. Compounds containing halogens ( ... The same requirements for McLafferty rearrangement apply to ortho rearrangement except for the strong α,β carbon-carbon double ... An example is the cleavage of carbon-carbon bonds next to a heteroatom. In this depiction, single-electron movements are ...
The technique has been improved through the use of stable isotopes to better trace energy flow through the web.[14] It was once ... A gradient exists between trophic levels running from complete autotrophs that obtain their sole source of carbon from the ... Ecologists employ stoichiometry to analyze the ratios of the main elements found in all organisms: carbon (C), nitrogen (N), ... and carbon dioxide, water, and heat). Excretion of nutrients is, therefore, basic to metabolism."[28]:1230-1231 The units in ...
There is evidence from oxygen isotopes at Deep Sea Drilling Program sites that ice began to build up in Antarctica about 36 Ma ... The higher organic content and water retention of the deeper and richer grassland soils, with long term burial of carbon in ... A Middle Miocene δ18O increase, that is, a relative increase in the heavier isotope of oxygen, has been noted in the Pacific, ... which are able to assimilate carbon dioxide and water more efficiently than C3 grasses, expanded to become ecologically ...
They used density gradient centrifugation to determine which isotope or isotopes of nitrogen were present in the DNA after ... It was determined to have 712 carbon, 1,130 hydrogen, 243 oxygen, two sulfur atoms, and at least one iron atom. This gave ... and Stahl's famous experiment in which they proved that DNA replication is semi-conservative by using different isotopes of ...
Flerov, G. N. (1967). "On the nuclear properties of the isotopes 256103 and 257103". Nucl. Phys. A. 106 (2): 476. Bibcode: ... Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon ... The first atoms of lawrencium were produced by bombarding a three-milligram target consisting of three isotopes of the element ... The fourth element, either actinium or lawrencium, has only radioactive isotopes. Actinium, which occurs only in trace amounts ...
Radionuclides used in PET scanning are typically isotopes with short half-lives[3] such as carbon-11 (~20 min), nitrogen-13 (~ ... A few other isotopes and radiotracers are slowly being introduced into oncology for specific purposes. For example, 11C- ... Instead, the isotope must be prepared first, then afterward, the chemistry to prepare any organic radiotracer (such as FDG) ... The emitted positron travels in tissue for a short distance (typically less than 1 mm, but dependent on the isotope[34]), ...
Carbon isotope ratios suggest P. boisei had a diet dominated by C4 vegetation, unlike P. robustus in South Africa. ... The foods that P. boisei would have ingested can be determined by means of carbon isotope measurements (not to be confused with ... carbon isotope data on P. boisei fossils suggest that their diet was largely based on C4 resources, probably grasses or sedges ...
Iso-tope Abun-dance Hauf-life (t1/2) Decay mode Pro-duct ... Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium ...
The difference between soft and hard body parts stems mostly from the fact that carbon has a very low X-ray cross section ... Applied Radiation and Isotopes. 50 (1): 125-36. doi:10.1016/S0969-8043(98)00044-X. PMID 10028632.. ... and exit various materials such as carbon steel and other metals. Specific methods include industrial computed tomography. ...
The removal of land to clear way for palm oil plantations releases carbon emissions held in the peatlands of Indonesia.[166][ ... Special Theme: Case Studies of Neodymium Isotopes in Paleoceanography. 29 (19-20): 2591-2603. Bibcode:2010QSRv...29.2591C. doi: ... Rising levels of carbon dioxide are resulting in influx of this gas into the ocean, increasing its acidity. Marine organisms ... Using chemical proxies from Antarctic ice cores, researchers have estimated the fluctuations of carbon dioxide (CO2) and ...
Examples include pulmonary function testing (e.g. nitrogen washout test, diffusion capacity testing (carbon monoxide, helium, ... methane)) and diagnostic radiology (eg.radioactive xenon isotopes). Therapeutic[edit]. Gases and other drugs used in ...
Primordial isotopes of the alkali metals Z. Alkali metal. Stable. Decays. unstable: italics. odd-odd isotopes coloured pink ... Reaction with carbon Lithium is the only metal that reacts directly with carbon to give dilithium acetylide. Na and K can react ... No primordial isotopes. (223. Fr. is a radiogenic nuclide) Radioactive: 40K, t1/2 1.25 × 109 years; 87Rb, t1/2 4.9 × 1010 years ... They also react with carbon dioxide and carbon tetrachloride, so that normal fire extinguishers are counterproductive when used ...
Ti and Ta carbides have high melting points due to covalent carbon networks although carbon vacancies often exist in these ... Boron acts as a "burnable" neutron absorber because its two isotopes, 10B and 11B, both transmute into stable nuclear reaction ... 2002). "A thermoanalytical study on the oxidation of ZrC and HfC powders with formation of carbon". Solid State Ionics. 149 (3- ... Metal carbides are brittle due to the strong bonds that exist between carbon atoms. The largest class of carbides, including Hf ...
Main isotopes of gadolinium. [[Isotope,IsoÀdàkọ:Shytope]] [[Natural abundance,AbunÀdàkọ:Shydance]] Half-life (t1/2) Decay mode ... Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon ...
Carbon dioxide. Carbon dioxide concentration during the mid Pliocene has been estimated at around 400 ppmv from 13C/12C ratio ... The formation of an Arctic ice cap is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North ... "The last time carbon dioxide concentrations were around 400ppm: a snapshot from Arctic Siberia". Skeptical Science. Retrieved ... The intensity of the sunlight reaching the earth, the global geography, and carbon dioxide concentrations were similar to ...
Soddy first used the word "isotope" in: Soddy, Frederick (4 December 1913). "Intra-atomic charge". Nature. 92 (2301): 399-400. ... the halogens group or separately above the table between boron and carbon.[25] ... They became known as isotopes, from the Greek eisos topos ("same place").[11][27] ...
2 in the atmosphere as a source of carbon, in a process called carbon fixation (they are autotrophs). This process involves ... Manhesa, Gérard; Allègre, Claude J.; Dupréa, Bernard & Hamelin, Bruno (1980). "Lead isotope study of basic-ultrabasic layered ... Methanogens also play a critical role in the carbon cycle, breaking down organic carbon into methane, which is also a major ... Organic compounds or carbon fixation. Ferroglobus, Methanobacteria or Pyrolobus Organotrophs. Organic compounds Organic ...
Changing Climate: Report of the Carbon Dioxide Assessment Committee. Washington, D.C.: National Academy Press. 1983.. (The full ... working on isotope separation,[2] before returning to Columbia to complete his PhD. ...
Earliest evidence for life based on unusually high amounts of light isotopes of carbon, a common sign of life. 4280[36]. ... a b c d For more information on this, see Atmosphere of Earth#Evolution of Earth's atmosphere, Carbon dioxide in the Earth's ... Carbon-. iferous[g]. Pennsylvanian Gzhelian Winged insects radiate suddenly; some (esp. Protodonata and Palaeodictyoptera) are ... It has evolved to describe an "epoch" starting some time in the past and on the whole defined by anthropogenic carbon emissions ...
"for his research on the carbon dioxide assimilation in plants"[۲۳] ۱۹۶۲ ماکس پراتز[۲۴] United Kingdom "for their studies of the ... "for his work on the use of isotopes as tracers in the study of chemical processes"[۲۲] ...
This is because naturally occurring carbon is a mixture of the isotopes 12C, 13C and 14C which have masses of 12 u, 13.003355 u ... Note that this also differs subtly from the molecular mass in that the choice of isotopes is defined and thus is a single ... The precision of the molar mass is limited by the highest variance standard atomic weight, in this example that of carbon. This ... Moreover, the proportion of the isotopes varies between samples, so 12.011 g/mol is an average value across different places on ...
Part 2. Lithium aluminum hydride reduction of the electron-rich carbon-carbon double bond conjugated with the indole nucleus ... Blanc, Aurélien; Bochet, Christian G. (2007). "Isotope Effects in Photochemistry: Application to Chromatic Orthogonality". Org ... deprotection is demonstrated in a photochemical transesterification by trimethylsilyldiazomethane utilizing the kinetic isotope ...
In the late 1960s, several companies, including ARCO in the USA, developed isotope-powered pacemakers, but this development was ... dissolved oxygen or carbon dioxide levels) in the arterial-venous system, physical activity as determined by an accelerometer, ...
In a blast furnace, iron oxide, a compound, reacts with carbon monoxide to form iron, one of the chemical elements, and carbon ... atoms of an element which have different mass numbers are known as isotopes. For example, all atoms with 6 protons in their ... of carbon-12, where the carbon-12 atoms are unbound, at rest and in their ground state.[24] The number of entities per mole is ... From left to right: the elements tin (Sn) and sulfur (S), diamond (an allotrope of carbon), sucrose (pure sugar), and sodium ...
Estimation of feeding history by measuring carbon and nitrogen stable isotope ratios in hair of Asiatic black bears. Ursus 16: ...
These two isotopes are nearly identical in all respects, including their molecular weights. The problem was ultimately solved ... please sign up as the mentor for Carbon emissions reporting and Micro hydro on the course page, and leave notes introducing ... by Francis Simon and Nicholas Kurti, when they figured out that the two isotopes could be separated by gaseous diffusion. ...
... such as carbon-14, via the reaction: n + 14N → p + 14C. Cosmic rays kept the level of carbon-14[81] in the atmosphere roughly ... Cosmic rays are also responsible for the continuous production of a number of unstable isotopes in the Earth's atmosphere, ... Carbon and oxygen nuclei collide with interstellar matter to form lithium, beryllium and boron in a process termed cosmic ray ... Carbon-14 (5730 years): 14N(n, p)14C (neutron activation) ... are heavier nuclei of the elements such as carbon, iron, and ...
Estimating dissolved organic carbon concentration. *Specific ultraviolet absorbance for metric of aromaticity ...
Carbon. Latin carbo. 6. &012.0107812.0107(8)[২][৩]. 14. 2 ... indicates the mass number of the longest-lived isotope of the ...
a b Georgia Tech (2008-02-11). Carbon Capture Strategy Could Lead to Emission-Free Cars. Siaran pers. Diakses pada 2008-03-16. ... Clayton, Donald D. (2003). Handbook of Isotopes in the Cosmos: Hydrogen to Gallium. Cambridge University Press. ISBN 0521823811 ... B. (2004). "Spectroscopy of superheavy hydrogen isotopes in stopped-pion absorption by nuclei". Physics of Atomic Nuclei. 68 (3 ... Kendall, Carol (1998). "Fundamentals of Isotope Geochemistry". US Geological Survey. Diakses pada 8 Maret 2008. ...
The naturally occurring isotopes of carbon, of which there are three: 12C making up about 98.9 per cent; 13C about 1.1 per cent ... carbon isotopes Natural carbon is composed of three isotopes: 12C making up about 98.9%; 13C about 1.1%; and 14C whose amount ... carbon isotopes The naturally occurring isotopes of carbon, of which there are three: 12C making up about 98.9 per cent; 13C ... Carbon-isotope dating is a method of radiometric age-dating using the amount of the heavy, radioactive isotope carbon-14 ...
Carbon Isotopes, Photosynthesis, and Archaeology: Different pathways of photosynthesis cause characteristic changes in carbon ... Carbon isotope ratio data in bone collagen from human skeletons found in Illinois, Ohio, and West Virginia, dated 4,000 B.C. to ... scientists measured carbon isotopes in the collagen tissues of human skeletons from North America. ... isotope ratios that make possible the study of prehistoric human diets. American Scientist 1982; 70(6):596-606. ...
... carbon: In 1961 the isotope carbon-12 was selected to replace oxygen as the standard relative to which the atomic weights of ... Carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radiolabeling. ... In carbon. In 1961 the isotope carbon-12 was selected to replace oxygen as the standard relative to which the atomic weights of ... Carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radiolabeling. ...
Main isotopes of carbon .mw-parser-output .nobold{font-weight:normal}. (6C). Iso-tope Decay ... The isotopes parameter[edit]. Isotopes are to be entered by the editor in ,isotopes=. , using one subtemplate for each ... isotopes table footnote=* = [[excited state]]{{sfn,Chisté,2006}} , isotopes = {{Infobox element isotopes/isotopes stable , link ... isotopes =,!-- the parameter --, {{Infobox element isotopes/isotopes stable , mn=19 , sym=F , link=fluorine-19 , na=100 ...
Los Gatos Research is developing a simple robust methodology for the determination of carbon isotope ratios in small gas ... With such a sensitive method of accurately determining carbon isotope levels we hope to significantly advance the prospects for ... The isotope ratio is known to be a sensitive indicator of biologic activity. The new innovative advancement we propose to make ... of 1.5 microns in Phase I and demonstrate that the approach can be used to record the relative isotopic abundance of carbon 12 ...
Has 1 halo neutron Has 2 halo neutrons Carbon-11 or 11C is a radioactive isotope of carbon that decays to boron-11. This decay ... Stable carbon isotopes in carbon dioxide are utilized differentially by plants during photosynthesis.[citation needed] Grasses ... Carbon (6C) has 15 known isotopes, from 8C to 22C, of which 12C and 13C are stable. The longest-lived radioisotope is 14C, with ... Plants find it easier to use the lighter isotopes (12C) when they convert sunlight and carbon dioxide into food. So, for ...
A Dual-Carbon-and-Nitrogen Stable Isotope Ratio Model Is Not Superior to a Single-Carbon Stable Isotope Ratio Model for ... For nitrogen isotopes in meat products, variability was constrained, relative to carbon isotopes. The entire range in δ15N ... We turned to carbon and nitrogen stable isotopes to tell us the origin of the animals diet, based on classical models (1, 2) ... Carbon and nitrogen stable isotopes in fast food: Signatures of corn and confinement. A. Hope Jahren and Rebecca A. Kraft ...
Carbon Isotopes in the Carbon Cycle. Since all carbon isotopes are the same chemically they can all interact with other atoms ... of carbon atoms are called Isotopes ("same type"). Chemically, they all act like carbon atoms, they all "look" like carbon ... to use the lighter isotopes of carbon: 12C over 13C over 14C. So if you took a plant and measured what isotopes it has you ... carbon-12 or 12C. But a small number of carbon atoms have an extra neutron, carbon-13, or 13C and an even smaller number of ...
Evaluating Dissolved Inorganic Carbon Cycling in a Forested Lake Watershed Using Carbon Isotopes - Volume 34 Issue 3 - Ramon ... Carbon fluxes, pCO2 and substrate weathering in a large northern river basin, Canada: carbon isotope perspectives. Chemical ... Carbon fluxes, pCO2 and substrate weathering in a large northern river basin, Canada: carbon isotope perspectives. Chemical ... A rapid and precise method for measuring stable carbon isotope ratios of dissolved inorganic carbon. Marine Chemistry, Vol. 69 ...
We compared carbon isotope ratios from four types of experimental colonies: feral, managed with and without supplemental feed, ... Kelly, J.F. (2000) Stable isotopes of carbon and nitrogen in the study of avian and mammalian trophic ecology. Can. J. Zool. 78 ... Brosi, A.R., Harkins, W.D. (1937) The abundance ratio of the isotopes in natural or isotopically separated carbon. Phys. Rev. ... Overmyer, J.P., MacNeil, M.A., Fisk, A.T. (2008) Fractionation and metabolic turnover of carbon and nitrogen stable isotopes in ...
Isotope Analysers in Agriculture focuses on an isotopic technique that scientists are using to assess the presence of carbon ... The IAEA publication Use of Laser Carbon Dioxide Carbon ... Use of Laser Carbon Dioxide Carbon Isotope Analysers in ... New IAEA Publication - Use of Laser Carbon Dioxide Carbon Isotope Analysers in Agriculture. ×. ... The recently published Use of Laser Carbon Dioxide Carbon Isotope Analysers in Agriculture focuses on this specific technique, ...
The studies show that the carbon isotope discrimination (CID), which is the ratio of the variation of carbon-13 to carbon-12 in ... INTERNATIONAL ATOMIC ENERGY AGENCY, Greater Agronomic Water Use Efficiency in Wheat and Rice Using Carbon Isotope ... Greater Agronomic Water Use Efficiency in Wheat and Rice Using Carbon Isotope Discrimination. ... Greater Agronomic Water Use Efficiency in Wheat and Rice Using Carbon Isotope Discrimination ...
Organic carbon contains less of the stable isotope Carbon-13, or 13C, relative to the initial inorganic carbon from the ... Understanding these variations in carbon fractionation across species is applied in isotope geochemistry and ecological isotope ... Carbon on Earth naturally occurs in two stable isotopes, with 98.9% in the form of 12C and 1.1% in 13C. The ratio between these ... "On the Relationship Between Carbon Isotope Discrimination and the Intercellular Carbon Dioxide Concentration in Leaves". ...
Illustration of the structures of the nuclei of two isotopes each of carbon (bottom) and hydrogen (top). The nuclei are made up ... Carbon-13 (lower right) has an overall nuclear spin (unlike carbon-12), and so is used in nuclear magnetic resonance ... Hydrogen-1 (upper left) and carbon-12 (lower left) each make up over 98% of these elements. ... of nucleons (balls). There are two types of nucleon: protons (grey) and neutrons (white). Isotopes, chemically- identical ...
... to identify residency in juvenile nursery habitats with distinctive carbon isotope values. Conventional bulk... ... Stable carbon isotope analysis of amino-acid enantiomers by conventional isotope ratio mass spectrometry and combined gas- ... Carbon isotopes in otolith amino acids identify residency of juvenile snapper (Family: Lutjanidae) in coastal nurseries. ... Rodelli MR, Gearing JN, Gearing PJ, Marshall N, Sasekumar A (1984) Stable isotope ratio as a tracer of mangrove carbon in ...
One culture exhibited a change in the fractionation pattern for carbon (but not for hydrogen) midway through the... ... Methane-oxidizing bacteria, however, can significantly change the carbon isotopic composition of methane; the origin of gas ... We cultured methane-oxidizing bacteria at two different temperatures and monitored the carbon and hydrogen isotopic ... Carbon isotopic analysis of methane has become a popular technique in the exploration for oil and gas because it can be used to ...
Case Studies in Isotope Stratigraphy, Volume Five in the Advances in Sequence Stratigraphy series, covers current research ... Ordovician carbon isotope stratigraphy of China: a synthesis Chao Li and Yuandong Zhang 8. Comparative carbon isotope ... 1. Carbon isotope stratigraphy. principles and applications Darren R. Gröcke 2. Interpreting Phanerozoic ?13C patterns as ... Stable carbon isotopes in archaeological plant remains Juan Pedro Ferrio, Mònica Aguilera, Jordi Voltas and José Luis Araus 4. ...
... high-resolution deglacial record of the stable isotopic composition of carbon in CO2(δ(13)C-CO2) in air extracted from ice … ... Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation Proc Natl Acad Sci U S A ... high-resolution deglacial record of the stable isotopic composition of carbon in CO2(δ(13)C-CO2) in air extracted from ice ... C-CO2 that suggest rapid oxidation of organic land carbon or enhanced air-sea gas exchange in the Southern Ocean. Additional ...
stable isotopes, carbon fluxes, environmental factors, Planning Links:. planid: 4110 myp: ECO ltg: ECO-6 Goal: 4 obj: 405 ... Stable isotopes are used widely as a tool for determining sources of carbon (C) fluxes in ecosystem C studies. Environmental ... Stable isotopes are used widely as a tool for determining sources of carbon (C) fluxes in ecosystem C studies ... Soil drying effects on the carbon isotope composition of soil respiration. Contact. National Health and Environmental Effects ...
Conversation: Isotope changes in marine organic carbon. Subject: [ISOGEOCHEM] Isotope changes in marine organic carbon. Does ... Carbon isotope signatures were also independent of rock type and depositional environment, showing that the carbon isotope ... two positive carbon-isotope excursions in a range of materials are separated by an abrupt negative shift. Carbon-isotope ... Carbon-isotope stratigraphy proves to be most useful as a monitor of the history of the carbon-cycle during the last 200 ...
Carbon isotopes laser separation by multiple-photon dissociation O. N. Avatcov, A. B. Bakhtadze, V. Yu. Baranov, V. S. Doljikov ... "Carbon isotopes laser separation by multiple-photon dissociation," Appl. Opt. 23, 26-29 (1984) ... Laser isotope separation of rare earth elements N. V. Karlov, B. B. Krynetskii, V. A. Mishin, and A. M. Prokhorov. Appl. Opt. ... Laser Isotope Separation Using Two-Photon Selective Excitation; Its Quantum Efficiency and Separation Factor Yung S. Liu. Appl ...
The 13C isotopes reflect an organic origin for the carbon. This carbon came from the diagenesis of organic matter caused by an ... Stable carbon and oxygen isotope ratios (δ13C and δ18O) of the epibenthic foraminiferan Elphidium macellum var. aculeatum were ... Using stable isotopes of nitrogen and carbon to study seabird ecology: applications in the Mediterranean seabird community , El ... Using stable isotopes of nitrogen and carbon to study seabird ecology: applications in the Mediterranean seabird community ...
Carbon-isotope analyses of fossil plants as a chemostratigraphic and palaeoenvironmental tool. ... GRÖCKE, D. R. (1998), Carbon-isotope analyses of fossil plants as a chemostratigraphic and palaeoenvironmental tool. Lethaia, ...
The use of stable carbon isotopes in metabolic research on humans has expanded significantly since the early 1980s. This is due ... The use of stable carbon isotopes in metabolic research on humans has expanded significantly since the early 1980s. This is due ... Carbon Isotope Ratio Mass Spectrometric Studies in Medicine. International Conference & Exihibition On Analytical and ... human diet is derived from food items from plants following the C 3 photosynthetic pathway which display more negative carbon- ...
Buy Carbon Isotope Techniques by David C. Coleman at TextbookX.com. ISBN/UPC: 9780121797317. Save an average of 50% on the ... Description: Carbon Isotope Techniques is a hands-on introduction to using carbon isotope tracers in experimental biology and ... and archaeology will find Carbon Isotope Techniques a valuable resource. Key Features. * Features isotopes in ecological ... The 11C, 12C, 13C, and 14C carbon isotopes are considered and standard techniques are described by established authors. This is ...
Thus far, no study has systematically examined intraindividual coupled strontium (Sr), oxygen (O), and carbon (C) isotope ... Strontium, oxygen, and carbon isotope variation in modern human dental enamel. Am J Phys Anthropol. 2020. ... Thus far, no study has systematically examined intraindividual coupled strontium (Sr), oxygen (O), and carbon (C) isotope ... MATERIAL AND METHODS: This study presents the first systematic results on intraindividual variation in Sr-O-C isotope ...
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Carbon and oxygen stable isotope compositions of late Pleistocene mammal teeth from dolines of Ajoie (Northwestern Switzerland ... Van der Merwe, N.J., and Medina, E. The canopy effect, carbon isotope ratios and foodwebs in Amazonia. Journal of ... Cerling, T.E., and Harris, J.M. Carbon isotope fractionation between diet and bioapatite in ungulate mammals and implications ... Kohn, M.J. Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate. Proceedings ...
Isotope ratio measurements have been conducted on a series of isotopically distinct pure CO2 gas samples using the technique of ... Metrology for stable isotope reference materials: 13C/12C and 18O/16O isotope ratio value assignment of pure carbon dioxide gas ... Isotope metrology, Isotope reference material, SI traceability, VPDB-CO2 traceability, ?13C, DI-IRMS ... www.nist.gov/publications/metrology-stable-isotope-reference-materials-13c12c-and-18o16o-isotope-ratio-value ...
... plants indicated that photorespiratory carbon isotope fractionation, opposite in sign when compared to the carbon isotope ... carbon isotope shifts of CO2 relative to the C-1-carboxyl carbon of glycine varied from +14 parts per thousand to -7 parts per ... Carbon isotope effects were investigated for the reaction catalyzed by the glycine decarboxylase complex (GDC; EC 2.1.2.10). ... Decarboxylation of glycine contributes to carbon isotope fractionation in photosynthetic organisms. Igamberdiev, A U ...
  • The degree of carbon isotope fractionation is influenced by several factors, including the metabolism, anatomy, growth rate, and environmental conditions of the organism. (wikipedia.org)
  • Understanding these variations in carbon fractionation across species is useful for biogeochemical studies, including the reconstruction of paleoecology, plant evolution, and the characterization of food chains. (wikipedia.org)
  • Understanding these variations in carbon fractionation across species is applied in isotope geochemistry and ecological isotope studies to understand biochemical processes, establish food chains, or model the carbon cycle through geological time. (wikipedia.org)
  • Isotope fractionation due to Rubisco (form I) carboxylation alone is predicted to be a 28‰ depletion, on average. (wikipedia.org)
  • One culture exhibited a change in the fractionation pattern for carbon (but not for hydrogen) midway through the experiment, suggesting that bacterial oxidation of methane may occur via more than one pathway. (usgs.gov)
  • The terrestrial distribution of carbon isotopes between igneous rocks and sediments is discussed with reference to the available meteoritic determinations.Isotopic fractionation between iron carbide and graphite in meteorites may indicate the mechanism by which early fractionation between deep seated and surface terrestrial carbon may have occurred. (uvm.edu)
  • The measurement of delta C-13 in the leaves of the GDC-deficient barley ( Hordeum vulgare L.) mutant (LaPr 87/30) plants indicated that photorespiratory carbon isotope fractionation, opposite in sign when compared to the carbon isotope effect during CO2 photoassimilation, takes place in vivo. (diva-portal.org)
  • Thus the key reaction of photorespiration catalyzed by GDC, together with the key reaction of CO2 fixation catalyzed by ribulose-1,5-bisphosphate carboxylase, both contribute to carbon isotope fractionation in photosynthesis. (diva-portal.org)
  • To investigate the scale, and to determine the origin of the nitrogen isotope heterogeneity (source vs. fractionation during diamond-formation) shown for populations of mantle diamonds we have determined multiple δ 13 C-δ 15 N values and nitrogen abundances from 14 monocrystalline (MCDs) and 25 polycrystalline diamonds (PCDs) using step-wise oxidation gas sourced mass spectrometry. (open.ac.uk)
  • However, there are samples that show much larger heterogeneities for δ 13 C and δ 15 N values (≤ 23‰ and ≤ 33‰ respectively), which cannot be generated by equilibrium stable isotope fractionation during, or prior to diamond-formation. (open.ac.uk)
  • Microbial biodegradation of thermogenic C2+ hydrocarbon gases in Indiana coalbeds preferentially targets C3 and introduces isotope fractionation whereby remaining C3 is enriched in heavy hydrogen and carbon isotopes. (iu.edu)
  • Compound specific isotope analysis (CSIA) has proven to be a useful means of assessing transformation pathways according to characteristic stable isotope fractionation patterns. (rsc.org)
  • The C and N isotope fractionation of DNAN associated with abiotic and enzymatic hydrolysis was recently assessed. (rsc.org)
  • The extent to which DNAN isotope fractionation will be affected by other potentially competing transformation pathways known for nitroaromatic compounds ( e.g. , reduction) and if previous knowledge can be extrapolated to other environmental matrices remains to be understood. (rsc.org)
  • Here, we investigated the C and N isotope fractionation and reaction rate constants of DNAN during abiotic reduction mediated by mineral-associated Fe( II ) species as a function of mineral type, natural organic matter presence, and repeated exposures to DNAN. (rsc.org)
  • Chikaraishi Y, Naraoka H, Poulson SR (2004a) Carbon and hydrogen isotopic fractionation during lipid biosynthesis in a higher plant (Cryptomeria japonica). (springer.com)
  • Abstract-Lipid biomarkers and 13 C fractionation patterns were used to understand the dynamics of carbon cycling during microbial metabolisms in different environments of travertine precipitation (called facies) at Spring AT-1 on Angel Terrace in the Mammoth Hot Springs complex of Yellowstone National Park, USA. (montana.edu)
  • The rates of respiration in light and darkness, C i/C a and carbon isotope fractionation were investigated in glycine decarboxylase-deficient plants of barley, potato and Arabidopsis thaliana grown in climate chambers with controlled light intensity, temperature, humidity, irradiation and different CO2 concentrations (360, 700 and 1400 µl l-1) and compared to the wild-type plants. (diva-portal.org)
  • We determined the carbon isotope content at different CO2 concentrations to calculate the contribution of both C i/C a and photorespiration for 13C/12C fractionation. (diva-portal.org)
  • The direct effect of photorespiration was in the range of 0.7-1.0permil, from which we calculated the value of fractionation at the site of glycine decarboxylation as being 10-13permil, which is in agreement with the previously reported carbon isotope discrimination exerted by the glycine decarboxylase. (diva-portal.org)
  • It is concluded that photorespiration participates in the regulation of C i/C a and contributes to carbon isotope fractionation, both via effects on stomata and via discrimination of 13C in the glycine decarboxylase reaction. (diva-portal.org)
  • The new approach provides an accurate description of dual-isotope effects regardless of the extent of the isotope fractionation and physical characteristics of the experimental system. (dtu.dk)
  • The advantages of our self-consistent dual isotope modeling approach proved to be most evident when isotope fractionation factors of carbon and chlorine differed significantly and for systems with mass-transfer limitations, where both physical and (bio)chemical transformation processes affect the observed isotopic values. (dtu.dk)
  • This research demonstrates new approaches for exploring past p CO 2 via the carbon isotope fractionation in general algal lipids, which we test over a high CO 2 gradient from a naturally occurring CO 2 seep. (biogeosciences.net)
  • Here we help to constrain changing sources with a high-precision, high-resolution deglacial record of the stable isotopic composition of carbon in CO2(δ(13)C-CO2) in air extracted from ice samples from Taylor Glacier, Antarctica. (nih.gov)
  • This study presents the first systematic results on intraindividual variation in Sr-O-C isotope composition and Sr concentration in modern human dental enamel of third molars (affected and unaffected by caries). (americanelements.com)
  • Single loci and bulk sampling approaches of third molars established that a single analysis is only representative of the bulk Sr isotope composition in 60% of the elements analyzed. (americanelements.com)
  • The influence of instrumental parameters, data normalization schemes on the metrological traceability and uncertainty of the sample isotope composition have been characterized. (nist.gov)
  • Here we analyze the stable isotope composition of soil and stream carbon dioxide and demonstrate that methane production and mixing of carbon sources also occur in soils and streams. (diva-portal.org)
  • As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. (nerc.ac.uk)
  • The project aims to produce a 7500-year record of climate and tree response to climate forcing in Northern Finland on the basis of the carbon isotope composition of cellulose in tree rings. (luomus.fi)
  • The stable (non-radioactive) isotopic composition of carbon, δ 13 C, of the cellulose reflects photosynthetic production and has a strong correlation to growing season temperature (Hilasvuori et al. (luomus.fi)
  • misc{osti_1415736, title = {SPRUCE S1 Bog Pretreatment Fungal Hyphae Carbon and Nitrogen Concentrations and Stable Isotope Composition from In-growth Cores, 2013-2014}, author = {Hofmockel, K. S. and Chen, J. and Hobbie, E. A.}, abstractNote = {This data set reports fungal hyphal carbon and nitrogen concentrations and δ13C, and δ15N data for samples obtained from in-growth cores in the S1 Bog. (osti.gov)
  • Variations in Stable Carbon Isotope Composition and Leaf Traits of Picea schrenkiana var. (hindawi.com)
  • H. Zhang, J. Ma, W. Sun, and F. Chen, "Variations in stable carbon isotope composition and leaf traits of Picea schrenkiana var. (hindawi.com)
  • Stable carbon isotope composition ( δ 13 C) provides an integrated measurement of internal plant physiological and external environmental properties influencing photosynthetic gas exchange over the time when the carbon was fixed [ 1 , 2 ]. (hindawi.com)
  • However, this application requires better understanding of relationships between carbon isotope composition and plant physiological and morphological characteristics. (hindawi.com)
  • As a result of variation in environmental factors, such as temperature, precipitation, photosynthetically active radiation, and atmospheric CO 2 concentration along altitudinal gradients, changes in morphological and physiological traits and leaf carbon isotope composition in alpine plants are expected. (hindawi.com)
  • Therefore, altitudinal gradients provide unique experimental opportunities to study morphological and physiological responses of plants to environmental factors, as well as relationships between leaf carbon isotope composition and leaf morphological and physiological characteristics [ 9 - 14 ]. (hindawi.com)
  • The isotopic composition of carbon (Δ 14 C and δ 13 C) in atmospheric CO 2 and in oceanic and terrestrial carbon reservoirs is influenced by anthropogenic emissions and by natural carbon exchanges, which can respond to and drive changes in climate. (geosci-model-dev.net)
  • We compiled existing historical datasets to define the annual mean carbon isotopic composition of atmospheric CO 2 for 1850-2015 that can be used in CMIP6 and other modelling activities. (geosci-model-dev.net)
  • In the present study, BVOC emissions, and their carbon isotope composition from two Mediterranean species, Quercus suber L. and Cistus ladanifer L. were investigated under field conditions in June and July 2018. (frontiersin.org)
  • Hence, the increasing photosynthetic discrimination had a cascading effect on the natural carbon isotope composition of the emitted BVOCs over time. (frontiersin.org)
  • Here, we demonstrate that the natural carbon isotope composition may provide a robust framework to elucidate biosynthetic pathways of various BVOCs under field conditions. (frontiersin.org)
  • Stable carbon isotope composition of perirenal adipose tissue fatty acids from Engadine sheep grazing either mountain or lowland pasture. (biomedsearch.com)
  • Carbon stable isotopic composition was determined for zooplankton, POM, DOM and, in two cases, phytoplankton from 12 small forest lakes in southern Finland during summer 1997. (lancs.ac.uk)
  • Bi X, Sheng G, Liu X, Li C, Fu J (2005) Molecular and carbon and hydrogen isotopic composition of n -alkanes in plant leaf waxes. (springer.com)
  • Chikaraishi Y (2006) Carbon and hydrogen isotopic composition of sterols in natural marine brown and red macroalgae and associated shellfish. (springer.com)
  • In both cases, however, their carbon isotope composition is characterized by low variability and does not correlate with the species or physiological type of decomposer fungus but shows a statistically significant correlation with the degree of wood mineralization. (deepdyve.com)
  • This trophic shift lacks species specificity, is equally manifested in decomposers of deciduous and coniferous substrates, remains unchanged along the latitudinal climatic gradient, and is positively correlated with the carbon isotope composition of substrates, in the absence of correlation with the degree of their mineralization. (deepdyve.com)
  • Carbon and oxygen isotope composition of Nautilus macromphalus: a record of thermocline waters off New Caledonia. (antiqbook.nl)
  • In particular, it buffered the oxygen isotope composition of the calc-mylonite towards the relatively 18 O-depleted composition of the hanging wall Verrucano in the south and towards the relatively 18 O-enriched compositions of the footwall flysch in the north. (rero.ch)
  • Li, M.C., Liu, H.Y., Yi, X.F., Li, L.X.: Characterization of photosynthetic pathway of plant species growing in the eastern Tibetan plateau using stable carbon isotope composition. (springer.com)
  • The isotopic composition is determined with an isotope-ratio mass spectrometer (IRMS) technique. (atmos-meas-tech.net)
  • Photosynthetic pathway of steppe vegetation and the stable carbon isotope composition of organic matter in the Russian Chernozem. (usda.gov)
  • 1995). Plants find it easier to use the lighter isotopes (12C) when they convert sunlight and carbon dioxide into food. (wikipedia.org)
  • Photosynthesis converts carbon dioxide to carbohydrates via several metabolic pathways that provide energy to an organism and preferentially react with certain stable isotopes of carbon. (wikipedia.org)
  • This pathway converts inorganic carbon dioxide from the atmosphere or aquatic environment into carbohydrates, using water and energy from light, then releases molecular oxygen as a product. (wikipedia.org)
  • The overall equation for the light-dependent reactions is generally: 2 H2O + 2 NADP+ + 3 ADP + 3 Pi + light → 2 NADPH + 2 H+ + 3 ATP + O2 The light-independent reactions undergo the Calvin-Benson cycle, in which the energy from NADPH and ATP is used to convert carbon dioxide and water into organic compounds via the enzyme RuBisCO. (wikipedia.org)
  • The broad strokes of climate science may be grasped with a limited amount of scientific knowledge: carbon dioxide and other greenhouse gases absorb and release heat (infrared radiation). (skepticalscience.com)
  • Craig, H. (1957) Isotopic standards for mass spectrometric analysis of carbon dioxide. (springer.com)
  • An increasing number of scientists are using isotopic techniques to assess the presence of carbon dioxide (CO 2 ) in the environment and to enhance land management practices in order to reduce emissions from agriculture. (iaea.org)
  • The recently published Use of Laser Carbon Dioxide Carbon Isotope Analysers in Agriculture focuses on this specific technique, which helps make agriculture climate smart. (iaea.org)
  • Countries around the world are trying to produce no more greenhouse gases than necessary, and the laser carbon dioxide isotope analyser is a tool to help in CO 2 emission assessment to improve a country's agricultural management practices. (iaea.org)
  • Isotope standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide. (nii.ac.jp)
  • Plain Language Summary Large carbon dioxide emission to the atmosphere occurs as rainwater percolates through soils and into streams. (diva-portal.org)
  • However, less is known about the underlying processes that accompanies this transfer of carbon dioxide from soils to streams. (diva-portal.org)
  • Our results therefore demonstrate that the export of carbon dioxide from soils to streams not only results in emissions to the atmosphere but also represents a channel of transformation. (diva-portal.org)
  • This questions some of our current conceptualization of the catchment-scale cycling of carbon dioxide. (diva-portal.org)
  • Tree-ring stable carbon isotope ratios (delta C-13) often display a decline over the industrial period (post-AD1850) that is only partly explained by changes in the isotopic ratio of carbon dioxide (CO2) and may represent a response to increased atmospheric concentrations Of CO2 (ca). (columbia.edu)
  • We present a novel, cross-disciplinary approach combining turbulence observations, wavelet analysis, and high time resolution stable isotope ratio measurements to directly quantify component fluxes of carbon dioxide at the atmosphere-vegetation interface, and to improve our understanding of important pathways for energy and mass transport in forests. (confex.com)
  • The approach is based on identifiable changes in the correlation structure of carbon dioxide and water vapor concentrations in the canopy air during updrafts. (confex.com)
  • The two methods are combined to evaluate the hypothesis that short-term excursions from similarity theory predictions of the correlation structure between carbon dioxide and water vapor are associated with the vertical transport through coherent structures. (confex.com)
  • The working hypothesis is that the stable isotope signatures can be traced back to different sinks and sources of water vapor and carbon dioxide in the canopy, and subsequently be integrated into the conditional sampling scheme to directly quantify ecosystem-scale photosynthesis and respiration fluxes. (confex.com)
  • The ratios of oxygen-18 to oxygen-16 (^(18)O/^(16)O) of cellulose purified from two sets of wheat plants grown under conditions similar in all respects except for a large difference in the^(18)O/^(16)O ratios of the carbon dioxide supplied to them differ by only a small amount. (caltech.edu)
  • These results indicate that the oxygen derived from carbon dioxide undergoes complete exchange with the oxygen of the water in the plant during the synthesis of cellulose and that the ^(18)O/^(16)O ratio of the water inside the plant is the primary influence on the ^(18)O/^(16)O ratio of cellulose in terrestrial plants. (caltech.edu)
  • The low carbon isotope ratios of tree-ring cellulose during the last century, reflecting anthropogenic disturbance of atmospheric carbon dioxide, are thus overestimated. (nerc.ac.uk)
  • Bender, M.M.: Variations in the 13 C/ 12 C ratios of plants in relation to the pathway of photosynthetic carbon dioxide fixation. (springer.com)
  • Craig, H.: Isotope standards for carbon and oxygen and correlation factors for mass spectrometric analysis of carbon dioxide. (springer.com)
  • Carbon dioxide concentrations ( p CO 2 ) in the atmosphere play an integral role in Earth system dynamics, especially climate. (biogeosciences.net)
  • Carbon dioxide concentrations ( p CO 2 ) in the atmosphere play an integral role in Earth system. (biogeosciences.net)
  • CO is extracted from an air sample and converted into carbon dioxide (CO 2 ) using the Schütze reagent. (atmos-meas-tech.net)
  • Carbon Isotopes, Photosynthesis, and Archaeology: Different pathways of photosynthesis cause characteristic changes in carbon isotope ratios that make possible the study of prehistoric human diets. (hhmi.org)
  • Oxygenic photosynthesis takes place in plants and microorganisms through different chemical pathways, so various forms of organic material reflect different ratios of 13C isotopes. (wikipedia.org)
  • So applications using stable carbon isotopes have developed from initially categorizing photosynthetic pathways (C 3 , C 4 , and CAM) to evaluating more critical impacts of environmental conditions on leaf photosynthesis [ 3 - 9 ]. (hindawi.com)
  • Abstract Los Gatos Research is developing a simple robust methodology for the determination of carbon isotope ratios in small gas samples. (sbir.gov)
  • abstract = "We propose a self-consistent method to predict the evolution of carbon and chlorine isotope ratios during degradation of chlorinated hydrocarbons. (dtu.dk)
  • Fig. 1 depicts the results of all stable isotope analyses according to the location of food purchase within the U.S. (pnas.org)
  • Conventional bulk otolith and muscle stable isotope analyses (SIA) and essential amino acid (AA) SIA were conducted on snapper collected from seagrass beds, mangroves, and coral reefs in the Red Sea, Caribbean Sea, and Pacific coast of Panama. (springer.com)
  • Carbon and oxygen analyses of enamel were performed on forty-six teeth of large mammals ( Equus germanicus , Mammuthus primigenius , Coelodonta antiquitatis , and Bison priscus ), coming from one doline in Boncourt (~ 80 ka, marine oxygen isotope stage MIS5a) and seven in Courtedoux (51-27 ka, late MIS3), in order to reconstruct the paleoclimatic and paleoenvironmental conditions of the region. (cambridge.org)
  • The use of carbon isotopes in novel evaluation of the ESMs' component ocean and terrestrial biosphere models and in new analyses of historical changes may improve predictions of future changes in the carbon cycle and climate system. (geosci-model-dev.net)
  • In this study, we present the results of carbon and nitrogen isotope analyses of 18 faunal (including two domesticated dogs) and 58 adult human skeletons excavated from the Moyoro site of the Okhotsk culture in eastern Hokkaido. (nii.ac.jp)
  • Stable carbon and nitrogen isotope analyses of human and animal tissues have become an important means of studying both anthropogenic and natural food webs in aquatic ecosystems. (frontiersin.org)
  • Microbial mats that encrust travertine deposits were collected for analyses of lipid biomarkers and carbon isotopes along the continuous drainage outflow system of Spring AT-1. (montana.edu)
  • Compared to conventional methods, the laser CO 2 carbon isotope analyser is more robust and can provide continuous real-time measurements of CO 2 concentration emitted by the soil. (iaea.org)
  • To provide reliable data, the analyser must be used with care: "Although laser isotope analysers are easier to operate than conventional analytic equipment, the results could easily be inaccurate if the measurements, instrument calibration and data management are not done properly," Heiling explained. (iaea.org)
  • Isotope ratio measurements have been conducted on a series of isotopically distinct pure CO2 gas samples using the technique of dual-inlet isotope ratio mass spectrometry (DI-IRMS). (nist.gov)
  • Here, this study demonstrates that carbon isotope data can be used to constrain stomatal conductance and intrinsic water use efficiency in CLM, as an alternative to eddy covariance flux measurements. (osti.gov)
  • It is a form of isotope ratio mass spectrometry that can provide either measurements of total compound equivalents or, when coupled to separation technology such as chromatography, quantitation of specific compounds. (unt.edu)
  • The 'pyrolysis adjustment', proposed here, is based on combusting a stratified sub-sample of the pyrolysis results, across the full range of carbon isotope ratios, and using the paired results to define a regression equation that can be used to adjust all the pyrolysis measurements. (nerc.ac.uk)
  • Carbon isotope measurements show that individuals buried at Sanga ate diets rich in C 4 -based resources, and suffered high rates of dental caries, similar to those seen among farmers in southern Africa. (brillonline.com)
  • This dataset contains measurements of carbon and nitrogen isotopes in biological material collected from three levels in the ocean (POM, plankton, benthos) from the HLY-02-01 cruise. (ucar.edu)
  • In this study, we developed a new system for online measurements of δ 13 C in atmospheric carbonaceous aerosols by combining a semicontinuous organic carbon/elemental carbon (OC/EC) analyzer and online cavity ring-down spectroscopy (CRDS) (OC/EC analyzer-CRDS). (picarro.com)
  • Our results showed that the accuracy and absolute precision of the δ 13 C measurements by the OC/EC analyzer-CRDS system were better than 0.1‰ and 0.5‰, respectively, for the samples containing carbon content more than 5 μg. (picarro.com)
  • Joint carbon and nitrogen isotope measurements were made from chlorins (chlorophyll a, phaeophytin a and pyrophaeophytin a) extracted from the last glacial-interglacial transition sediments of Lake Suigetsu, central Japan. (semanticscholar.org)
  • New isotope data obtained from relatively conformable, carbonate-rich strata of the Ediacaran Yangtze platform in South China reveal substantial delta C-13 variability. (columbia.edu)
  • Although phytoplankton were 13 C-depleted relative to POM, their abundance and their variability between lakes did not appear to explain adequately the observed trend in zooplankton stable isotope ratios. (lancs.ac.uk)
  • Ballentine DC, Macko SA, Turekian VC (1998) Variability of stable carbon isotopic compositions in individual fatty acids from combustion of C4 and C3 plants: implications for biomass burning. (springer.com)
  • Superimposed on a long-term cooling trend, the middle Maastrichtian is characterized by deep-sea warming and relatively high values of stable carbon-isotope ratios, followed by strong climatic variability towards the end of the Cretaceous. (open.ac.uk)
  • Low-amplitude variations (up to 0.4‰) in carbon isotopes at Site U1403 match similar scale variability in records from Tethyan and Pacific open-ocean sites. (open.ac.uk)
  • Variability along the frontier: stable carbon and nitrogen isotope ratio analysis of human. (deepdyve.com)
  • As more scientists, technicians and students turn to laser isotope analysers as an alternative to conventional methods, such as gas chromatography and isotope ratio mass spectroscopy, to track the amount and isotopic signature of CO 2 in the atmosphere, emitted from soil, microorganisms and plants, there is an increasing demand for guidance on the proper usage of such analysers, Heiling said. (iaea.org)
  • A multiloci sampling approach (n = 6-20) was used to analyze surface and inner enamel, employing thermal ionization mass spectrometry (TIMS) and isotope ratio mass spectrometry (IRMS). (americanelements.com)
  • We present an improved micro-extraction gas-chromatography continuous-flow isotope ratio mass spectrometer (CF-IRMS) method to extract and measure the methane C-13/C-12 ratio (delta(CH4)-C-13) of air occluded in glacial ice. (epfl.ch)
  • Stable carbon isotope ratios (δ(13)C values in ‰ vs. Vienna Pee Dee Belemnite standard) were determined in the composite samples by elemental analyzer-isotope ratio mass spectrometry. (biomedsearch.com)
  • The δ(13)C of the individual fatty acids were measured by gas chromatography-combustion-isotope ratio mass spectrometry. (biomedsearch.com)
  • A large number (3074) of tree-ring α-cellulose samples are used to compare the stable carbon isotope ratios (δ13C) produced by high-temperature (1400°C) pyrolysis/gas chromatography (GC)/isotope ratio mass spectrometry (IRMS) with those produced by combustion GC/IRMS. (nerc.ac.uk)
  • Carbon-isotope dating is a method of radiometric age-dating using the amount of the heavy, radioactive isotope carbon-14 remaining in organic matter . (encyclopedia.com)
  • Organic carbon contains less of the stable isotope Carbon-13, or 13C, relative to the initial inorganic carbon from the atmosphere or water because photosynthetic carbon fixation involves several fractionating reactions with kinetic isotope effects. (wikipedia.org)
  • These two trends, related to marine sources, are punctuated at 16.3 and 12.9 ka with abrupt, century-scale perturbations in δ(13)C-CO2 that suggest rapid oxidation of organic land carbon or enhanced air-sea gas exchange in the Southern Ocean. (nih.gov)
  • Hi Tim, Using the keywords: marine, organic carbon, and atmospheric CO2 with a search on my ref database (over 30,000 refs just on stable isotopes) the selection, as given below, was generated (including abstracts). (uvm.edu)
  • Marine organic carbon lies in a range intermediate between these groups. (uvm.edu)
  • A similar pattern in the concentration of chlorophyll a (Chl-a), particulate organic nitrogen (PON) and particulat (mas) e organic carbon (POC) was observed in both mesocosms. (worldwidescience.org)
  • Existing atmospheric models underestimate concentrations of aerosol particulate matter and create gaps in our understanding of the atmospheric organic carbon budget, especially in relation to aqueous phase reactions that occur in fog and clouds. (epa.gov)
  • The outcomes of my research will provide clarification of the atmospheric organic carbon budget that could ideally be applied to total organic carbon and help ameliorate uncertainties in atmospheric models. (epa.gov)
  • 10 parts per thousand) surface-to-deep ocean delta C-13 gradient that is consistent with long-term deep ocean anoxia and the presence of a large dissolved organic carbon (DOC) reservoir. (columbia.edu)
  • A timescale for dissolved organic carbon production in equatorial {P}acific surface waters, Global Biogeochem. (clim-past.net)
  • The combined data for C, H and N isotopes makes it highly unlikely that the CH_3OH-soluble components are derivable from, or simply related to, the insoluble organic polymer found in the same meteorites. (caltech.edu)
  • Either there are large isotopic fractionations for carbon and hydrogen between different soluble organic phases, or the less polar components are partially of terrestrial origin. (caltech.edu)
  • To effectively use stable isotopes in the field, there is the need to determine the changes in stable isotope values occurring from the microbial degradation of organic components such as NAs which contribute a significant portion to the dissolved organic carbon (DOC) in reclamation sites. (uwaterloo.ca)
  • DOC and DIC concentration and carbon stable isotope values were determined for water sampled from 13 oil sands aquatic reclamation sites varying in age, construction and organic material. (uwaterloo.ca)
  • During the last 30 years, stable isotope analysis has emerged as one of most powerful tools for tracing organic carbon in food webs. (plos.org)
  • However, fatty acids account for only a small fraction of total organic carbon fluxes, and they tend to undergo degradation and transformation during food web passage [6] . (plos.org)
  • Amino acids (AAs), in contrast, account for the large majority of organic nitrogen, and about half of total carbon in most organisms [7] and therefore are among the major conduits of carbon through food chains. (plos.org)
  • This data set contains data on particulate organic nitrogen concentration and particulate organic carbon concentration as well as stable isotope ratios for carbon and nitrogen determined in melted sea ice samples collected during the Bering Sea Ecosystem Study-Bering Sea Integrated Ecosystem Research Program (BEST-BSIERP) 2008 (HLY0801, HLY0802), 2009 (HLY0901, HLY0902) and 2010 (PESA10-01) field studies. (ucar.edu)
  • The world's largest continental shelf, the East Siberian Shelf Sea, receives substantial input of terrestrial organic carbon (terr-OC) from both large rivers and erosion of its coastline. (biogeosciences.net)
  • To better understand the fate of this terr-OC, molecular (acyl lipid biomarkers) and isotopic tools (stable carbon and radiocarbon isotopes) have been applied to both particulate organic carbon (POC) in surface water and sedimentary organic carbon (SOC) collected from the underlying surface sediments. (biogeosciences.net)
  • Isotope data were used to trace the advection of northward flowing organic material through the Bering Strait into the Chukchi and Bering Seas. (ucar.edu)
  • This is interpreted as due to remineralization of organic carbon within the carbonate rocks. (lyellcollection.org)
  • This study explored the potential for otolith geochemistry in snapper (Family: Lutjanidae) to identify residency in juvenile nursery habitats with distinctive carbon isotope values. (springer.com)
  • The geochemistry of the stable carbon isotopes. (uvm.edu)
  • There are three naturally occurring isotopes of carbon: 12, 13, and 14. (wikipedia.org)
  • Mitochondria isolated from leaves of pea (Pisum sativum L.) and spinach (Spinacia oleracea L.) were incubated with glycine, and the CO2 evolved was analyzed for the carbon isotope ratio (delta C-13). (diva-portal.org)
  • Different organisms fix carbon through different mechanisms, which are reflected in the varying isotope compositions across photosynthetic pathways (see table below, and explanation of notation in "Carbon Isotope Measurement" section). (wikipedia.org)
  • We cultured methane-oxidizing bacteria at two different temperatures and monitored the carbon and hydrogen isotopic compositions of the residual methane. (usgs.gov)
  • The oxygen and carbon isotope compositions of the sediment deposits in the various Central Asian basins have already been used to decipher both the topographic and climatic changes that occurred in that region during the Cenozoic, generally concentrating on one sedimentary section and/or on a limited time range and either using multiple-type samples including sandstone calcitic cements, marine carbonates, fossils, or paleosols. (mdpi.com)
  • Isotope analysis of fatty acids in conjunction with their structural compositions are now widely used to investigate biosynthetic sources since their molecular structure are tied to their biosynthetic origins (e.g. [5] ). (plos.org)
  • however, these studies rarely consider the complex and dynamic nature of the carbon and nitrogen cycles that give structure to nutrient regimes and their isotopic compositions in freshwater ecosystems. (frontiersin.org)
  • Typically, stable carbon (δ 13 C) and nitrogen (δ 15 N) isotopic compositions of human, plant, and animal tissues are expected to reflect broadly predictable patterns according to factors such as trophic level, photosynthetic pathway, and environmental conditions (for review see Lee-Thorp, 2008 ). (frontiersin.org)
  • Oxygen isotope compositions of surface waters (delta O-18(w)) estimated from turtle and crocodile delta O-18(p) values range from -5.0 +/- 1.0 parts per thousand to -2.4 +/- 1.0 parts per thousand, which do not differ from mean annual rainwater values occurring today under inter-tropical sub-arid to arid climates. (ipgp.fr)
  • Integrated Ocean Drilling Program (IODP) Expedition 311 at the Cascadia Margin, northeastern Pacific, provides an excellent opportunity to study the response of carbon isotopic compositions of benthic foraminifers to episodic methane seep events in a gas hydrate geosystem. (geoscienceworld.org)
  • 12 C ratios of carbon fluxes and pools. (osti.gov)
  • Since these essential AAs (EAAs) typically pass from food source to consumer without alteration to their carbon skeletons [8] , [9] , a method for tracking their origins and fluxes could greatly advance our understanding of nutrient cycling and trophic relationships. (plos.org)
  • Bowling DR, Tans PP, Monson RK (2001) Partitioning net ecosystem carbon exchange with isotopic fluxes of CO2. (springer.com)
  • Broadmeadow MSJ, Griffiths H (1993) Carbon isotope discrimination and the coupling of CO 2 fluxes within forest canopies. (springer.com)
  • A high-resolution carbon-isotope record from bulk carbonates allows us to identify global trends in the late Maastrichtian carbon cycle. (open.ac.uk)
  • This study emphasizes the potential for isotope geochemical preservation in carbonates despite extensive dolomitization and identifies the timing and local environmental conditions capturing the SPICE. (illinois.edu)
  • In this regard, natural abundant stable carbon isotope ratios (δ 13 C) of BVOCs may provide a powerful tool to evaluate different metabolic pathways. (frontiersin.org)
  • suggested the investigation of the stable carbon isotope ratio of 13 C/ 12 C (δ 13 C) at natural abundance as a powerful tool to reveal individual biosynthetic pathways for BVOCs. (frontiersin.org)
  • Carbon-isotope fractionations, on the other hand, can provide insight into the operating biosynthetic pathways associated with different organisms in the changing environment. (montana.edu)
  • In diagenetic studies (see DIAGENESIS ), measurement of the ratio of carbon-13 to carbon-12 allows the recognition of carbonate precipitated from a variety of different sources. (encyclopedia.com)
  • Analytical Validation of Accelerator Mass Spectrometry for Pharmaceutical Development: the Measurement of Carbon-14 Isotope Ratio. (unt.edu)
  • Accelerator mass spectrometry (AMS) is an isotope based measurement technology that utilizes carbon-14 labeled compounds in the pharmaceutical development process to measure compounds at very low concentrations, empowers microdosing as an investigational tool, and extends the utility of {sup 14}C labeled compounds to dramatically lower levels. (unt.edu)
  • The isotope ratio measurement was specific (owing to the {sup 14}C label), stable across samples storage conditions for at least one year, linear over 4 orders of magnitude with an analytical range from one tenth Modern to at least 2000 Modern (instrument specific). (unt.edu)
  • Measurement of the concentration and stable isotope ratios of methane from air enclosures in ancient ice can aid in understanding the temporal dynamics of methane sources and sinks. (epfl.ch)
  • Since these techniques are very costly, any methodological development which can provide simultaneous measurement of stable carbon and oxygen isotope ratios in cellulose deserves further exploration. (nerc.ac.uk)
  • This methodology allows simultaneous measurement of the stable isotopes of carbon and oxygen using high-temperature pyrolysis, reducing the amount of sample required and the analytical costs of measuring them separately. (nerc.ac.uk)
  • In this project, stable carbon isotopes will be used to track the progress of atmospheric aqueous phase reactions to determine if these processes affect particulate matter concentrations. (epa.gov)
  • Carbon content constitutes a major fraction of atmospheric particulate matter (PM) and directly influences the earth's climate and human health. (picarro.com)
  • Furthermore, we employed this system to monitor δ 13 C (δ 13 C-TC) in particulate total carbon (TC) with a time resolution of 2-4 h over Beijing in late summer and early autumn, 2019. (picarro.com)
  • Though rate constants varied, N and C apparent kinetic isotope effects (AKIEs) remained consistent across all experiments (averaged values of 15 N-AKIE = 1.0317 ± 0.0064 and 13 C-AKIE = 1.0008 ± 0.0005) and revealed significant 15 N- and minimal 13 C-enrichment in agreement with previous work on nitroaromatic compounds. (rsc.org)
  • With the advent of new continuous flow technologies, compound specific isotope analysis is increasingly employed as a complementary tool for food web analysis. (plos.org)
  • The detailed record of Lake 227 nutrient concentration, phytoplankton assemblages, and trophic state changes allows for a detailed look at the standard interpretations of sediment core isotopes and the information that can be gained from their study. (uwaterloo.ca)
  • In the inversion analysis, oxygen isotope information is jointly applied with concentration information. (suny.edu)
  • Also, various methods combining the concentration and isotopic ratios were tested to maximize the benefit of including isotope information. (suny.edu)
  • δ18Odiatom and δ13Cdiatom from 11,990 to 11,530 cal years BP allow us to reconstruct shifts in the precipitation/evaporation ratio and changes in the lake water dissolved carbon concentration, respectively. (lancs.ac.uk)
  • We will demonstrate the new absorption analysis technique at wavelengths of 1.5 microns in Phase I and demonstrate that the approach can be used to record the relative isotopic abundance of carbon 12 and 13 with great accuracy. (sbir.gov)
  • The first section of this publication provides step-by-step procedures with figures and photos on how to create reference gases for isotope analysis, followed by guidance on how to use the analyser in a continuous free-flow mode. (iaea.org)
  • Carbon isotopic analysis of methane has become a popular technique in the exploration for oil and gas because it can be used to differentiate between thermogenic and microbial gas and can sometimes be used for gas-source rock correlations. (usgs.gov)
  • 13C value, indicating that combined carbon and hydrogen isotopic analysis may be an effective way of identifying methane which has been subjected to partial oxidation by bacteria. (usgs.gov)
  • In situ laser microprobe techniques for stable isotope analysis. (nii.ac.jp)
  • This is coupled with the analysis of the carbon isotopic fingerprint of light components at the wellsite. (onepetro.org)
  • Stable isotope analysis can enhance this understanding. (uwaterloo.ca)
  • These results reveal the potential of carbon and nitrogen isotope analysis for questions regarding migration and mobility. (soton.ac.uk)
  • talks.cam : Compound-specific carbon isotope analysis of lipid combustion residues from herbivore dung. (cam.ac.uk)
  • Stable isotope analysis of zooplankton carbon nutrition in humic lakes. (lancs.ac.uk)
  • The analysis of carbon and hydrogen stable isotope ratios of lipids from natural products is an integral component of research in Earth sciences. (springer.com)
  • Isotope-assisted metabolic flux analysis (isotope MFA) combines experimental and computational techniques to analyze complex metabolic networks and thus to evaluate intracellular carbon flow and partitioning. (umd.edu)
  • Stable isotope analysis of cellulose is an increasingly important aspect of ecological and palaeoenvironmental research. (nerc.ac.uk)
  • Pickard, Catriona 2018-05-28 00:00:00 Carbon (δ13C) and nitrogen (δ15N) stable isotope analysis of human bone collagen from 38 individuals was undertaken to assess diet at the Late Roman-Early Byzantine (AD 300-700) cemetery site, Joan Planells, in Ibiza, Spain. (deepdyve.com)
  • SEM analysis of foraminifer tests and the comparative carbon isotopic analysis of previous works on this subject indicate minimal alteration caused by diagenesis and authigenic carbonate precipitation. (geoscienceworld.org)
  • INTERNATIONAL ATOMIC ENERGY AGENCY, Greater Agronomic Water Use Efficiency in Wheat and Rice Using Carbon Isotope Discrimination, IAEA-TECDOC-1671, IAEA, Vienna (2012). (iaea.org)
  • The studies show that the carbon isotope discrimination (CID), which is the ratio of the variation of carbon-13 to carbon-12 in plant samples (leaf and grain), is a good selection tool for identifying high yielding genotypes of wheat under drought stress environments for both pre-anthesis and post-anthesis stages. (iaea.org)
  • Cernusak LA, Ubierna N, Winter K et al (2013) Environmental and physiological determinants of carbon isotope discrimination in terrestrial plants. (springer.com)
  • Rundel, P.W., Esler, K.J., Cowling, R.M.: Ecological and phylogenetic patterns of carbon isotope discrimination in the winter rainfall flora of the Richterveld, South Africa. (springer.com)
  • The selective enrichment of one stable isotope over another creates distinct isotopic fractionations that can be measured and correlated among oxygenic phototrophs. (wikipedia.org)
  • Chikaraishi Y, Naraoka H, Poulson SR (2004b) Hydrogen and carbon isotopic fractionations of lipid biosynthesis among terrestrial (C3, C4 and CAM) and aquatic plants. (springer.com)
  • We used carbon and nitrogen stable isotopes to infer the source of feed to meat animals, the source of fat within fries, and the extent of fertilization and confinement inherent to production. (pnas.org)
  • Bouillon S, Raman AV, Dauby P, Dehairs F (2002) Carbon and nitrogen stable isotope ratios of subtidal benthic invertebrates in an estuarine mangrove ecosystem (Andhra Pradesh, India). (springer.com)
  • Hakenbeck, Susanne , McManus, Ellen , Geisler, Hans , Grupe, Gisela and O'Connell, Tamsin C. (2010) Diet and mobility in early medieval bavaria: a study of carbon and nitrogen stable isotopes. (soton.ac.uk)
  • The relative abundance of these isotopes varies and the study of this variation is an important tool in geologic research, especially radiometric dating . (encyclopedia.com)
  • Several hundred samples of carbon from various geologic sources have been analyzed in a new survey of the variation of the ratio C13/C12 in nature. (uvm.edu)
  • Strontium, oxygen, and carbon isotope variation in modern human dental enamel. (americanelements.com)
  • Thus far, no study has systematically examined intraindividual coupled strontium (Sr), oxygen (O), and carbon (C) isotope variation in human enamel or the effect that caries have on the isotopic integrity of the enamel. (americanelements.com)
  • Variation of hydrogen, carbon, nitrogen, and oxygen stable isotope ratios in an American diet: fast food meals. (biomedsearch.com)
  • Variation in stable isotope ratio values suggests individual differences in diet. (deepdyve.com)
  • These data highlight both the potential and difficulty of using chlorin-specific isotopes to track aquatic change from lake sediments. (semanticscholar.org)
  • Traceability to the Vienna PeeDee Belmnite(VPDB)-CO2 scale was realized using the pure CO2 isotope reference materials(IRMs) 8562, 8563, and 8564. (nist.gov)
  • The primary motivation for this compilation is to provide the atmospheric boundary condition for historical simulations in the Coupled Model Intercomparison Project 6 (CMIP6) for models simulating carbon isotopes in the ocean or terrestrial biosphere. (geosci-model-dev.net)
  • The stable carbon isotope ratios (δ 13 C) can be used to track potential sources and atmospheric processes of carbonaceous aerosols. (picarro.com)
  • 12C and 13C are measured as the isotope ratio δ13C in benthic foraminifera and used as a proxy for nutrient cycling and the temperature dependent air-sea exchange of CO2 (ventilation) (Lynch-Stieglitz et al. (wikipedia.org)
  • the observed photon costs can be accommodated by assuming coupled, energy-independent inorganic carbon influx and efflux. (uvm.edu)
  • Large CO2 evasion to the atmosphere occurs as dissolved inorganic carbon (DIC) is transported from soils to streams. (diva-portal.org)
  • Changes in stable isotopes values in the biomass (δ13C, δ15N), DOC and dissolved inorganic carbon (DIC) (δ13C) arising from degradation of the DOC were tracked in both static and semi-continuous tests. (uwaterloo.ca)
  • Results indicate that gas hydrate dissociation influenced the dissolved inorganic carbon of the pore water via anaerobic oxidation of methane. (geoscienceworld.org)
  • Oxygen isotopes also differ between the two sites, likely due to different sources of drinking water. (brillonline.com)
  • This data set reports fungal hyphal carbon and nitrogen concentrations and δ13C, and δ15N data for samples obtained from in-growth cores in the S1 Bog. (osti.gov)
  • Mass spectrometric determinations were made on the instruments developed by H. C. Image and his co-workers utilizing two complete feed systems with magnetic switching to determine small differences in isotope ratios between samples and a standard gas. (uvm.edu)
  • and 3) the completion of a multiyear whole lake isotope mass budget for Lake 227. (uwaterloo.ca)
  • At the Lochseite locality in the north, the isotope patterns indicate a vertical mass transport component from the footwall flysch to the hanging wall Verrucano with a time-integrated fluid flux of 2.6 m 3 / m2 . (rero.ch)
  • Carbon Isotope Stratigraphy, Vol 5. (researchandmarkets.com)
  • Case Studies in Isotope Stratigraphy, Volume Five in the Advances in Sequence Stratigraphy series, covers current research across many stratigraphic disciplines, providing information on the most recent developments for the geoscientific research community. (researchandmarkets.com)
  • 1. Carbon isotope stratigraphy principles and applications Darren R. Gröcke 2. (researchandmarkets.com)
  • Ordovician carbon isotope stratigraphy of China: a synthesis Chao Li and Yuandong Zhang 8. (researchandmarkets.com)
  • Carbon isotope stratigraphy of the Tournaisian (Lower Mississippian) successions of NE Europe Andrey V. Zhuravlev, Artem N. Plotitsyn, Denis A. Gruzdev and Irina V. Smoleva 10. (researchandmarkets.com)
  • Here, we review the basis of stable isotope biogeochemistry for these isotopic systems. (ipgp.fr)
  • The overall general equation for the light-independent reactions is the following: 3 CO2 + 9 ATP + 6 NADPH + 6 H+ → C3H6O3-phosphate + 9 ADP + 8 Pi + 6 NADP+ + 3 H2O The 3-carbon products (C3H6O3-phosphate) of the Calvin cycle are later converted to glucose or other carbohydrates such as starch, sucrose, and cellulose. (wikipedia.org)
  • Carbon-14 has a half-life of 5730 ± 40 years and the amount of the isotope present can be used to date materials up to about 50 000 years old (see RADIOCARBON DATING ). (encyclopedia.com)
  • Carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radiolabeling. (britannica.com)
  • 12 C and 13 C are "stable" isotopes which do not change, but 14 C is "radioactive" (often called "radiocarbon") and decays over time into nitrogen. (skepticalscience.com)
  • The likely explanation is that a proportion of the oxygen atoms are bonding with residual carbon in the reaction chamber to form carbon monoxide. (nerc.ac.uk)
  • Since carbon monoxide is one of the major sinks of hydroxyl radicals, it has been used as a proxy of hydroxyl radicals, which largely control the oxidizing capacity of the atmosphere. (suny.edu)
  • The ratio between these isotopes varies in biological organisms due to metabolic processes that selectively use one carbon isotope over the other, or "fractionate" carbon through kinetic or thermodynamic effects. (wikipedia.org)
  • The use of stable carbon isotopes in metabolic research on humans has expanded significantly since the early 1980s. (omicsonline.org)
  • The best definition for the base of the terminal Cambrian (Stage 10) is the conodont Eoconodontus notchpeakensis FAD ± onset of the HERB carbon isotope excursion. (nysed.gov)
  • The Cambrian Steptoean Positive Carbon Isotope Excursion (SPICE) is a well-documented global event that marked geochemical excursions in the world's oceans and terrestrial environments. (illinois.edu)
  • A core from the Franconia Formation, which lies on the southwestern edge of the Illinois Basin, appears to have captured the carbon-isotope excursion associated with the SPICE. (illinois.edu)
  • Circular 600, Geochemical Preservation of the Steptoean Positive Carbon Isotope Excursion (SPICE) Event in Dolomites of the Furongian Franconia Formation in the Illinois Basin by Dana M. Labotka and Jared T. Freiburg can be downloaded from the University of Illinois IDEALS repository . (illinois.edu)
  • We hypothesize that the rapid onset of the carbon isotope excursion (CIE) at the Paleocene/Eocene boundary (V55 Ma) may have resulted from the accretion of a significant amount of 12C-enriched carbon from the impact of a V10 km comet, an event that would also trigger greenhouse warming leading to the Paleocene/Eocene thermal maximum and, possibly, thermal dissociation of seafloor methane hydrate. (columbia.edu)
  • While bulk stable isotope values in otoliths showed regional differences, they failed to distinguish nursery residence on local scales. (springer.com)
  • The values of 13C/12C and 18O/16O isotope ratios are expressed relative to VPDB-CO2 using the and notation, respectively, in parts-per- thousand ( or per mil). (nist.gov)
  • Utilization of commercial and oil sands derived NAs resulted in minimal change of the DOC stable isotope values. (uwaterloo.ca)
  • The biomass was 13C enriched for both the commercial (0.3 to 2.9 per mil (‰)) and oil sands derived NAs (3.7 to 8.5 ‰) relative to the DOC stable isotope values. (uwaterloo.ca)
  • The carbon and nitrogen isotope values of mantle xenoliths and xenocrysts are used to trace the cycling of volatiles in the deep Earth, for example, to place empirical constraints on the origin of diamond-forming carbon in the mantle. (open.ac.uk)
  • By fragmenting single diamonds or using in-situ ion-beam techniques it is known that single diamonds can show large-scale heterogeneity for their carbon isotope values and nitrogen abundances, sometimes as large as entire populations of diamond across a few hundred micrometres. (open.ac.uk)
  • What is less well known is the scale of nitrogen isotope heterogeneity within single diamonds, and if the nitrogen isotope heterogeneity of single diamonds can provide an insight into why diamonds that show very restricted δ 13 C values show a much large range of δ 15 N values. (open.ac.uk)
  • From these 39 samples there are only 5 PCDs that show a larger range of carbon isotopes relative to nitrogen isotopes, but of these 5 samples only 2 show a range of δ 13 C values outside of analytical uncertainty. (open.ac.uk)
  • 10‰), whilst there is no relationship between the ranges of nitrogen isotope values for a given sample and the corresponding bulk δ 15 N value or nitrogen content. (open.ac.uk)
  • We found that δ 13 C AA patterns in contrast to bulk δ 13 C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. (plos.org)
  • Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs. (plos.org)
  • POM and DOM showed similar stable isotope ratios (δ 13 C around - 28‰, comparable with values commonly reported for terrestrial C3 vegetation) and these showed no relationship to water colour. (lancs.ac.uk)
  • Whereas the pre-K/Pg oscillations and the negative values of the Mid-Maastrichtian Event (MME) can be readily discerned in both the Zumaia and U1403 records, patterns diverge during a ~ 1 Myr period in the late Maastrichtian (67.8-66.8 Ma), with Site U1403 more reliably reflecting global carbon cycling. (open.ac.uk)
  • Carbon and oxygen isotopic values of these two species at Site U1327, U1328, and U1329 show episodic stratigraphic fluctuations, suggesting episodic gas hydrate dissociation and methane release possibly related to 100 ka sea-level fluctuations. (geoscienceworld.org)
  • The isotope and chronostratigraphical data together suggest that white laminae deposition is caused by extraordinary environmental events. (lancs.ac.uk)
  • With such a sensitive method of accurately determining carbon isotope levels we hope to significantly advance the prospects for making in-situ tests for evidence of life on nearby planets, such as Mars. (sbir.gov)
  • Although the mean human isotope ratios did not differ between sexes, the variances of carbon isotope ratios were significantly greater in males. (nii.ac.jp)
  • Carbon isotope ratio data in bone collagen from human skeletons found in Illinois, Ohio, and West Virginia, dated 4,000 B.C. to 1,500 A.D. The number and sex of the individuals found at each location are indicated in parentheses. (hhmi.org)
  • The data may also be useful for other carbon cycle modelling activities. (geosci-model-dev.net)
  • These data suggest that subduction induced nitrogen isotope heterogeneity may not be coupled with subduction induced carbon isotope heterogeneity in diamond-forming fluids. (open.ac.uk)
  • Ignat'ev, A. 2014-01-29 00:00:00 Data on the ratio of stable carbon isotopes in xylotrophic fungi and their xylic substrates are presented for the first time. (deepdyve.com)
  • EOL data archive -- HLY-02-01 Carbon and Nitrogen Isotope Dynamics (Excel) [Dunton, K. (ucar.edu)
  • This workshop will contribute to making progress through new regional syntheses of carbon isotope data throughout the last deglaciation and comparisons of these syntheses to other paleoclimate proxy reconstructions and isotope enabled model simulations. (oregonstate.edu)
  • For the latter purpose our carbon isotope syntheses and data constraints of ocean circulation will be useful. (oregonstate.edu)
  • Illustration of the structures of the nuclei of two isotopes each of carbon (bottom) and hydrogen (top). (sciencephoto.com)
  • Hydrogen-1 (upper left) and carbon-12 (lower left) each make up over 98% of these elements. (sciencephoto.com)
  • The stable isotopes of hydrogen, carbon, nitrogen, and oxygen provide insights into a heterotrophic organism's diet and geographic origin. (biomedsearch.com)