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.
Creation and development of bodies within solar systems, includes study of early planetary geology.
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)
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.
A plant genus of the family MELIACEAE. Members contain cedrelanolide.
El Nino-Southern Oscillation or ENSO is a cycle of extreme alternating warm El Niño and cold La Nina events which is the dominant year-to-year climate pattern on Earth. Both terms refer to large-scale changes in sea-surface temperature across the eastern tropical Pacific. ENSO is associated with a heightened risk of certain vector-borne diseases. (From http://www.elnino.noaa.gov/lanina_new_faq.html, accessed 5/12/2020)
The group of celestial bodies, including the EARTH, orbiting around and gravitationally bound by the sun. It includes eight planets, one minor planet, and 34 natural satellites, more than 1,000 observed comets, and thousands of lesser bodies known as MINOR PLANETS (asteroids) and METEOROIDS. (From Academic American Encyclopedia, 1983)
Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)
Small solar system planetary bodies including asteroids. Most asteroids are found within the gap lying between the orbits of Mars and Jupiter.
A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta.
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 carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
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.
The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
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.
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)
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)
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
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)
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)
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
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.
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.

A functional model for O-O bond formation by the O2-evolving complex in photosystem II. (1/649)

The formation of molecular oxygen from water in photosynthesis is catalyzed by photosystem II at an active site containing four manganese ions that are arranged in di-mu-oxo dimanganese units (where mu is a bridging mode). The complex [H2O(terpy)Mn(O)2Mn(terpy)OH2](NO3)3 (terpy is 2,2':6', 2"-terpyridine), which was synthesized and structurally characterized, contains a di-mu-oxo manganese dimer and catalyzes the conversion of sodium hypochlorite to molecular oxygen. Oxygen-18 isotope labeling showed that water is the source of the oxygen atoms in the molecular oxygen evolved, and so this system is a functional model for photosynthetic water oxidation.  (+info)

Towards the reaction mechanism of pyrogallol-phloroglucinol transhydroxylase of Pelobacter acidigallici. (2/649)

Conversion of pyrogallol to phloroglucinol was studied with the molybdenum enzyme transhydroxylase of the strictly anaerobic fermenting bacterium Pelobacter acidigallici. Transhydroxylation experiments in H218O revealed that none of the hydroxyl groups of phloroglucinol was derived from water, confirming the concept that this enzyme transfers a hydroxyl group from the cosubstrate 1,2,3, 5-tetrahydroxybenzene (tetrahydroxybenzene) to the acceptor pyrogallol, and simultaneously regenerates the cosubstrate. This concept requires a reaction which synthesizes the cofactor de novo to maintain a sufficiently high intracellular pool during growth. Some sulfoxides and aromatic N-oxides were found to act as hydroxyl donors to convert pyrogallol to tetrahydroxybenzene. Again, water was not the source of the added hydroxyl groups; the oxides reacted as cosubstrates in a transhydroxylation reaction rather than as true oxidants in a net hydroxylation reaction. No oxidizing agent was found that supported a formation of tetrahydroxybenzene via a net hydroxylation of pyrogallol. However, conversion of pyrogallol to phloroglucinol in the absence of tetrahydroxybenzene was achieved if little pyrogallol and a high amount of enzyme preparation was used which had been pre-exposed to air. Obviously, the enzyme was oxidized by air to form sufficient amounts of tetrahydroxybenzene from pyrogallol to start the reaction. A reaction mechanism is proposed which combines an oxidative hydroxylation with a reductive dehydroxylation via the molybdenum cofactor, and allows the transfer of a hydroxyl group between tetrahydroxybenzene and pyrogallol without involvement of water. With this, the transhydroxylase differs basically from all other hydroxylating molybdenum enzymes which all use water as hydroxyl source.  (+info)

Metabolism of (R)-(+)-pulegone and (R)-(+)-menthofuran by human liver cytochrome P-450s: evidence for formation of a furan epoxide. (3/649)

(R)-(+)-Pulegone, a monoterpene constituent of pennyroyal oil, is a hepatotoxin that has been used in folklore medicine as an abortifacient despite its potential lethal effects. Pulegone is metabolized by human liver cytochrome P-450s to menthofuran, a proximate hepatotoxic metabolite of pulegone. Expressed human liver cytochrome (CYP) P-450s (1A2, 2A6, 2C9, 2C19, 2D6, 2E1, and 3A4) were tested for their ability to catalyze the oxidations of pulegone and menthofuran. Expressed CYP2E1, CYP1A2, and CYP2C19 oxidized pulegone to menthofuran, with respective Km and Vmax values of 29 microM and 8.4 nmol/min/nmol P-450 for CYP2E1, 94 microM and 2.4 nmol/min/nmol P-450 for CYP1A2, and 31 microM and 1.5 nmol/min/nmol P-450 for CYP2C19. The human liver P-450s involved in the metabolism of menthofuran are the same as pulegone except for the addition of CYP2A6. These P-450s were found to oxidize menthofuran to a newly identified metabolite, 2-hydroxymenthofuran, which is an intermediate in the formation of the known metabolites mintlactone and isomintlactone. Based on studies with 18O2 and H218O, 2-hydroxymenthofuran arises predominantly from a dihydrodiol formed from a furan epoxide. CYP2E1, CYP1A2, and CYP2C19 oxidized menthofuran with respective Km and Vmax values of 33 microM and 0.43 nmol/min/nmol P-450 for CYP2E1, 57 microM and 0.29 nmol/min/nmol P-450 for CYP1A2, and 62 microM and 0.26 nmol/min/nmol P-450 for CYP2C19.  (+info)

Origin of graphitic carbon and pentlandite in matrix olivines in the Allende meteorite. (4/649)

Matrix olivines in the Allende carbonaceous chondrite are believed to have formed by condensation processes in the primitive solar nebula. However, transmission electron microscope observations of numerous matrix olivines show that they contain abundant, previously unrecognized, nanometer-sized inclusions of pentlandite and poorly graphitized carbon. Neither of these phases would have been stable at the high-temperature conditions required to condense iron-rich olivine in the solar nebula. The presence of these inclusions is consistent with formation of the olivines by parent body processes that involved overgrowth of fine-grained organic materials and sulfides in the precursor matrix materials.  (+info)

Butanol is superior to water for performing positron emission tomography activation studies. (5/649)

[15(O)]Butanol has been shown to be superior to [15(O)]water for measuring cerebral blood flow with positron emission tomography. This work demonstrates that it is also superior for performing activation studies. Data were collected under three conditions: a visual confrontation animal-naming task, nonsense figure size discrimination, and a nonvisual darkroom control task. Time-activity curves (TAC) were obtained for regions known to be activated by the confrontation naming task to compare absolute uptake and the different kinetics of the two tracers. Also, t statistic maps were calculated from the data of 10 subjects for both tracers and compared for magnitude of change and size of activated regions. Peak uptake in the whole-brain TAC were similar for the two tracers. For all regions and conditions, the washout rate of [15(O)]butanol was 41% greater than that of [15(O)]water. At a threshold of 0, the [15(O)]water and [15(O)]butanol percent difference (nonnormalized) and t statistic (global normalization) images are nearly identical, indicating that the same property is being measured with both tracers. The [15(O)]butanol parametric images displayed at a threshold of /t/ = 5 look similar to the [15(O)]water parametric maps displayed at a threshold of /t/ = 4, which is consistent with the observation that t statistic values in [15(O)]butanol images are generally greater. The t statistic values were equal when the [15(O)]butanol parametric map was created from any subset of 6 subjects and the [15(O)]water parametric map was created from all 10 subjects. Fewer subjects need to be studied with [15(O)]butanol to reach the same statistical power as an [15(O)]water-based study.  (+info)

Isotope dilution spaces of mice injected simultaneously with deuterium, tritium and oxygen-18. (6/649)

The isotope dilution technique for measuring total body water (TBW), and the doubly labelled water (DLW) method for measuring energy expenditure, are both sensitive to small variations in the ratio of the hydrogen to oxygen-18 dilution space. Since the dilution space ratio varies between individuals, there has been much recent debate over what causes this variability (i.e. physiological differences between individuals or analytical error in the isotope determinations), and thus which values (individual or a population mean dilution space ratio) should be employed for TBW and DLW calculations. To distinguish between physiological and analytical variability, we injected 15 non-reproductive and 12 lactating mice (Mus musculus, outbred MF1) simultaneously with deuterium, tritium and oxygen-18. The two hydrogen labels were administered and analysed independently, therefore we expected a strong correlation between dilution space ratios based on deuterium and tritium if most of the variation in dilution spaces was physiological, but only a weak correlation if most of the variation was analytical. Dilution spaces were significantly influenced by reproductive status. Dilution spaces expressed as a percentage of body mass averaged 15.7 % greater in lactating mice than in non-reproductive mice. In addition, the hydrogen tracer employed had a significant effect (deuterium spaces were 2.0 % larger than tritium spaces). Deuterium and tritium dilution spaces, expressed as a percentage of body mass, were highly correlated. Dilution space ratios ranged from 0.952 to 1. 146 when using deuterium, and from 0.930 to 1.103 when using tritium. Dilution space ratios based on deuterium and tritium were also highly correlated. Comparison of standard deviations of the dilution space ratio based on deuterium in vivo and in vitro indicated that only 4.5 % of the variation in the dilution space ratios observed in the mice could be accounted for by analytical variation in the deuterium and oxygen-18 analyses. Although our results include data which were outside the limits previously regarded as biologically possible, the correlations that we detected strongly suggest that variation in the observed dilution space ratio was mostly physiological rather than analytical.  (+info)

Mechanistic studies of phosphoserine phosphatase, an enzyme related to P-type ATPases. (7/649)

Phosphoserine phosphatase belongs to a new class of phosphotransferases forming an acylphosphate during catalysis and sharing three motifs with P-type ATPases and haloacid dehalogenases. The phosphorylated residue was identified as the first aspartate in the first motif (DXDXT) by mass spectrometry analysis of peptides derived from the phosphorylated enzyme treated with NaBH(4) or alkaline [(18)O]H(2)O. Incubation of native phosphoserine phosphatase with phosphoserine in [(18)O]H(2)O did not result in (18)O incorporation in residue Asp-20, indicating that the phosphoaspartate is hydrolyzed, as in P-type ATPases, by attack of the phosphorus atom. Mutagenesis studies bearing on conserved residues indicated that four conservative changes either did not affect (S109T) or caused a moderate decrease in activity (G178A, D179E, and D183E). Other mutations inactivated the enzyme by >80% (S109A and G180A) or even by >/=99% (D179N, D183N, K158A, and K158R). Mutations G178A and D179N decreased the affinity for phosphoserine, suggesting that these residues participate in the binding of the substrate. Mutations of Asp-179 decreased the affinity for Mg(2+), indicating that this residue interacts with the cation. Thus, investigated residues appear to play an important role in the reaction mechanism of phosphoserine phosphatase, as is known for equivalent residues in P-type ATPases and haloacid dehalogenases.  (+info)

Protein-water interaction studied by solvent 1H, 2H, and 17O magnetic relaxation. (8/649)

Previous studies of the magnetic field dependence of the magnetic relaxation rate of solvent protons in protein solutions have indicated that this dependence (called relaxation dispersion) is related to the rotational Brownian motion of the solute proteins. In particular, the dispersion of the longitudinal (spin-lattice) relaxation rate 1/T1 shows a monotonic decrease with increasing field, with an inflection point corresponding to a proton Larmor frequency which is inversely proportional to the orientational relaxation time of the protein. We have now compared the relaxation dispersion of solvent 1H, 2H, and 17O In aqueous solutions of lysozyme (molecular weight 14,700) and 1H and 2H in solutions of hemocyanin (molecular weight 14,7 00) and 1H and 2H in solutions of hemocyanin (molecular weight 9 x 10(6)). The main experimental observation is that the dispersion of the relaxation rates of the three solvent nuclei in lysozyme solutions, normalized to their respective rates in pure water, is essentially the same. This is also true for 1H and 2H relaxation in hemocyanin solutions. These results confirm that entire solvent water molecules, rather than exchanging protons, are involved in the interaction. We have been unable to deduce the correct mechanism to explain the data, but we can eliminate several interaction mechanisms from consideration. For example, all observations combined cannot be explained by a simple two-site model of exchange, in which water molecules are either in sites on the protein with a relaxation rate characteristic of these sites, or else in the bulk solvent (the observed relaxation rate being the weighted average of the two). Also eliminated is the class of models in which the protein molecules induce a preferential partial alignment of neighboring solvent molecules, for example by electrostatic interaction of the electric dipole moments of the water with the electric fields produced by surface charges of the protein molecules. In addition, the idea that relaxation of solvent nuclei is due, in the main, to interactions with protein protons is precluded. Rather, it appears that the protein molecules influence the dynamics of the motion of solvent water molecules in their neighborhood in a manner that imposes on all the solvent molecules a correlation time for their orientational relaxation which equals that of the solute proteins.  (+info)

TY - JOUR. T1 - Positional isotope exchange analysis of the Mycobacterium smegmatis cysteine ligase (MshC). AU - Williams, La Kenya. AU - Fan, Fan. AU - Blanchard, John S.. AU - Raushel, Frank M.. PY - 2008/4/22. Y1 - 2008/4/22. N2 - MshC catalyzes the ATP-dependent condensation of GlcN-Ins and cysteine to form Cys-GlcN-Ins, which is an intermediate in the biosynthetic pathway of mycothiol, i.e., 1-D-myo-inosityl-2-(N-acetyl-L-cysteinyl)amido-2-deoxy-α- D-glucopyranoside (MSH or AcCys-GlcN-Ins). MSH is produced by Mycobacterium tuberculosis, members of the Actinomycetes family, to maintain an intracellular reducing environment and protect against oxidative and antibiotic induced stress. The biosynthesis of MSH is essential for cell growth, and therefore, the MSH biosynthetic enzymes present potential targets for inhibitor design. The formation of kinetically competent adenylated intermediates was suggested by the observation of positional isotope exchange (PIX) reaction using [βγ-18O6]-ATP in ...
PANGAEA - Publishing Network for Geoscientific and Environmental Data. (Appendix E) Stable carbon and oxygen isotope composition of Globigerinoides sacculifera of ODP Hole 121-758B. Occurrence Dataset https://doi.org/10.1594/pangaea.759093 accessed via GBIF.org on 2017-12-15 ...
Single garnet crystals from a large, multicyclic hydrothermal system in Far East Russia are strongly growth zoned. Microscale ion microprobe analysis reveals consistent intracrystalline patterns in oxygen isotope composition and boron and iron contents, reflecting evolution of the hydrothermal system from magmatic- to meteoric-dominated conditions, and repetitive influx of magmatic fluids. Large intracrystalline variations in oxygen isotope composition (,12‰ δ18O) delimit temporal evolution of magmatic and meteoric fluid input within different portions of the hydrothermal system, and suggest that fluid-flow regimes differed between central and distal portions of the system. These results provide compelling evidence that microanalytical data can be extrapolated from intracrystalline scales to study macroscale processes in complex, large-scale fluid-rock systems. ...
Topographic development of the southern Washington Cascade Range and its influence on regional climate on the leeward side of the range for the past 15.6 m.y. are evaluated, using oxygen isotope ratios (δ18O) of ancient meteoric water recorded in authigenic smectites. The δ18O values of authigenic smectites from paleosols and altered tuffs on the east side of the range exhibit a temporal and continuous decrease of ∼3‰-4‰ from 15.6 Ma to the present. Taking into account a regional temperature change in eastern Washington since the middle Miocene, the calculated δ18O values of regional meteoric water show a negative shift of ∼3.5‰-4.5‰ over the same interval. Such a decrease is similar to the change in the δ18O values of modern precipitation from the coastal side to a region downwind of the Washington Cascades. This negative shift of the calculated δ18O values on the east side of the range is best explained by the development of a rain shadow due to the tectonic rock uplift of the ...
A recurrent interpretation of ancient climate based on the oxygen isotopic composition of marine carbonates and cherts suggests that Earths climate was substantially warmer in the distant past and remained so until as recently as 400 Myr ago. This interpretation is difficult to reconcile with the long-term glacial record, with evidence for modest weathering rates during most of Earths history, with biomarker and fossil evidence for eukaryotes and even vertebrates at times of anomalously low δ18O values, and with the predicted faintness of the young Sun. We argue here, following earlier suggestions, that the low δ18O values in ancient rocks are a consequence of the low δ18O of ancient seawater. A modest increase in ocean depth with time, together with progressive increases in pelagic sedimentation on midocean ridge flanks since about 550 Ma, could account for the variation in seawater isotopic composition. The required change in ocean depth, coupled with thinning of the oceanic crust, is a ...
Abstract The paper presents the principle of a method to measure infiltration rates in sewer systems based on the use of oxygen isotopes and its application in Lyon (France). Investigations in the urban area of Lyon benefit from the isotopic differences between underground waters originating from the two rivers Rhône and Saône and from their associated alluvial aquifers. The oxygen isotopic composition of the Rhône water is roughly 3 ‰ lighter than that of the Saône river, due to the large differences in the mean altitude and topographic situation of their catchments. Large amounts of water are pumped from the Rhône aquifer for drinking water supply. As a consequence, this difference in the oxygen isotopic composition between wastewater and local groundwater can be used to evaluate infiltration in sewers in some parts of the city. The results obtained in a case study allow to evaluate the reliability and the uncertainties of this method. ...
This dissertation investigates hydrological variability within tropical Asia over the past several few centuries as reflected in the stable oxygen isotope composition of atmospheric moisture. The stable isotopes of water in the climate system are unique tracers of moisture transport and tropical rainfall variability. The isotopic signal of atmospheric moisture within the tropics is transferred to cellulose of tropical trees during photosynthesis. Thus, the isotopic composition of tree cellulose can provide an archive of past hydrologic variability through isotopic reconstructions of the cellulose extracted from annual rings of long lived trees. The tropical atmospheric variability reflected in tropical trees can include variations in the Indian Monsoon and changes in moisture availability over Asia in response to the El Niño-Southern Oscillation (ENSO). Here an attempt has been made to better understand how the atmospheric dynamics associated within these climate phenomena influence the ...
This dissertation investigates hydrological variability within tropical Asia over the past several few centuries as reflected in the stable oxygen isotope composition of atmospheric moisture. The stable isotopes of water in the climate system are unique tracers of moisture transport and tropical rainfall variability. The isotopic signal of atmospheric moisture within the tropics is transferred to cellulose of tropical trees during photosynthesis. Thus, the isotopic composition of tree cellulose can provide an archive of past hydrologic variability through isotopic reconstructions of the cellulose extracted from annual rings of long lived trees. The tropical atmospheric variability reflected in tropical trees can include variations in the Indian Monsoon and changes in moisture availability over Asia in response to the El Niño-Southern Oscillation (ENSO). Here an attempt has been made to better understand how the atmospheric dynamics associated within these climate phenomena influence the ...
Oxygen isotope composition of main-group pallasites and mesosiderites. Data for main-group pallasites and mesosiderites from Greenwood et al. (2006). Solid lines through data points show the mean Δ17O value for each group. Grey-shaded boxes depict the 2σ error on the mesosiderite and main-group pallasite population Δ17O and δ18O mean values. Open squares are individual mesosiderite analyses, open circles individual pallasite analyses. The dashed line labelled (1) is the eucrite fractionation line of Greenwood et al. (2005); the dashed line labelled (2) shows the range of HED values obtained by Weichert et al. (2004). Δ17O is linearized using the format of Miller (2002): Δ17O = 1000 ln (1+ (δ17O/1000)) - λ1000 ln (1+ ( δ18O/1000)) where λ = 0.5247. TFL = Terrestrial Fractionation Line ...
Oxygen isotope composition of Martian meteorites. Data for Martian meteorites from Franchi et al. (1999) and compiled from laser fluorination analyses in the Meteoritical Bulletin. MFL: Martian fractionation line of Franchi et al. (1999), TFL: terrestrial fractionation line.Δ17O calculated as: Δ17O = δ17O - 0.52δ18O ...
The Antarctic Glaciological Data Center (AGDC) at NSIDC is pleased to announce the release of a new data set, the WAIS Divide WDC06A Oxygen Isotope Record. This data set contains complete low resolution (0.25 to 100 cm) oxygen isotope data from the WAIS Divide Ice Core WDC06A, 0 to 3404.7 m depth. Also included is the WDC2014 timescale.. ...
We measured the δ18O of cellulose (δ18Ocel) extracted from fossil wood collected at 9 sites in the northern and southern hemispheres as a potential source of information about precipitation δ18O (δ18Oppt) in the past and paleotemperatures. The samples had been buried in fluvial sediments for periods of time ranging from ca. 45 million to 250 years. At the oldest localities (high latitude, Eocene- through Pliocene-age sites in Canada and Russia), mean annual temperature (MAT) estimates derived from the modern relationship between MAT and δ18Ocel are 6-16°C lower than the MAT estimates derived from other biological proxies. Estimates of Pleistocene and Holocene mean annual temperatures are close to the modern values at those sites. These results are consistent with other recent findings that the MAT/δ18Oppt relationship across North America was not constant throughout the Cenozoic. Paleo-δ18Oppt estimates derived from fossil cellulose and the modern North American relationship between ...
Margaret Barbour holds a BSc in Biology and Earth Sciences and an MSc in Biology from the University of Waikato, New Zealand, and a PhD in Plant Science from the Australian National University. During her PhD she developed new understanding, and mechanistic models, of variability in the oxygen isotope composition of plant tissue. Her work was the first to theoretically describe and demonstrate the record of leaf evaporative environment present in the oxygen isotope composition of plant material. This work has subsequently been applied to reconstruct past climates from tree ring stable isotopes, as an indicator of plant regulation of water loss, and as a selection tool for yield in grain crops. Margaret was employed by Landcare Research in New Zealand from 2001 to 2009, where she led a Foundation-funded objective investigating the exchange of carbon dioxide in terrestrial systems at site scales, and the sensitivities and uncertainties of these processes to variation in climate, environmental and ...
We investigate the helium (He-3/He-4) and carbon (delta C-13) isotope compositions and relative abundance ratios (CO2/He-3) of gas samples together with the stable isotope compositions of dissolved carbon and sulfur and the oxygen and hydrogen isotopic compositions of the associated water phase from a number of geothermal fields located around Lake Van in eastern Anatolia, Turkey. The mantle-derived helium component, which is likely transferred to the crust beneath eastern Turkey by recent magmatism, is found to constitute up to 96% (e.g. Nemrut Caldera) of the total He content in fluids. As regards the spatial distribution of He, samples collected from areas of Pliocene-Quaternary volcanics are characterized by a wide and generally higher range of R/R-A ratios (0.93 to 7.76 R-A) compared to those of non-volcanic regions ((1.85 to 1.0 R-A). CO2/He-3 ratios vary over a wide range (2.4 x 10(5)-3.8 x 10(13)) but are mostly higher than that of the nominal upper mantle (similar to 2 x 10(9)). ...
Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl− concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in the southwestern Xisha Uplift, northern South China Sea (SCS). Pore water collected from a gravity-core inside of a mega-pockmark exhibits a downward Cl− concentration decrease concomitant with an increase in δ18O value at the interval of 5.7-6.7 mbsf. Concentrations of Cl−, Na+, and K+ mainly cluster along the seawater freshening line without distinct Na+ enrichment and K+ depletion. Thus, we infer that the pore water anomalies of Cl− concentrations and δ18O values are attributed to gas hydrate dissociation instead of clay mineral dehydration. Moreover, the lower δ18O values of sulfate in the target core (C14) than those in the reference core (C9) may be associated with the equilibrium oxygen fractionation during
Granger, J., M. G. Prokopenko, D. M. Sigman, C. W. Mordy, Z. M. Morse, L. V. Morales, R. N. Sambrotto, and B. Plessen (2011), Coupled nitrification-denitrification in sediment of the eastern Bering Sea shelf leads to (15)N enrichment of fixed N in shelf waters, J. Geophys. Res., 116, C11006, doi:10.1029/2010JC006751 ...
This thesis work is aimed at examining the oxygen atom mixing between common iron(III) oxides and Fe(II)aq solution during the sorption process. First, O labeled iron(III) minerals were used in batch sorption reactors to study the exchange of oxygen atom within the Fe(II)aq - iron(III) oxide system. Results showed a much lesser extent of oxygen mixing than reported Fe mixing from previous studies, even when dissolved Fe(II) is present. The oxygen mixing extents are 3.95 % more for goethite and 9.66 % more for ferrihydrite than their respective controls within 14 days. A consecutive atom exchange kinetic study indicated that O exchange is not inhibited by surface Fe sorptive site saturation, and that after 40d sorption experiment, the maximum O exchange is 54.96 % across reactors with different initial solid loadings and Fe(II)aq levels. The second part of this work examined the influence of aqueous Fe(II) on the sorption of selenium oxyanions (selenite and selenate) in Fe(II)aq - iron(III) systems. It
On the previous Isotope page, you learned a bit about what isotopes are, how they are obtained, and how the isotopes of certain elements are measured. Here, well elaborate on how to read carbon and oxygen isotope data and how the values are often interpreted by paleoclimatologists. Reading Isotope Data Measurements of carbon and oxygen…
Langer, G. , Ziveri, P. , Geisen, M. and Thoms, S. (2008): Oxygen isotope fractionation during calcification in Calcidiscus leptoporus: The influence of carbonate chemistry , European Geosciences Union, General Assembly 2008, 13 18 April, Vienna, Austria ...
Abstract. Stable oxygen isotope composition of atmospheric precipitation (δ18Op) was scrutinized from 39 stations distributed over Switzerland and its border zone. Monthly amount-weighted δ18Op values averaged over the 1995-2000 period showed the expected strong linear altitude dependence (−0.15 to −0.22‰ per 100 m) only during the summer season (May-September). Steeper gradients (~ −0.56 to −0.60‰ per 100 m) were observed for winter months over a low elevation belt, while hardly any altitudinal difference was seen for high elevation stations. This dichotomous pattern could be explained by the characteristically shallower vertical atmospheric mixing height during winter season and provides empirical evidence for recently simulated effects of stratified atmospheric flow on orographic precipitation isotopic ratios. This helps explain anomalous deflected altitudinal water isotope profiles reported from many other high relief regions. Grids and isotope distribution maps of the ...
In the next two lectures we will examine past climates (paleoclimates) and the forces. We have already discussed the importance of isotopes for rock dating. The ratio of these two oxygen isotopes has changed over the ages and these. Other factors which work in conjunction with the Earths orbital changes include.
The very neutron-rich oxygen isotopes 25O and 26O are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from 26F and 27F at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into 24O plus one or two neutrons, the 25O ground-state energy and width are determined, and upper limits for the 26O ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in 26O at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added ...
Carbon mineralogy, phosphorus and oxygen isotope records from the Late Pleistocene at ODP Hole 1198 A (Leg 194 Marion Plateau, Australia ...
Fertilizers Res. 45, 91-100. , 1961. Precipitation of silver phosphate from homogeneous solution. Anal. Chem. 33, 873-887. , 1982. UV-sensitive complex phosphorus: association with dissolved humic material and iron in a bog lake. Limnol. Oceonogr. 27, 564-569. , 2012. Variation in the photochemical lability of dissolved organic matter in a large boreal watershed. Aquatic Sci. 74, 751-768. , 1996. Inter- and intra-tooth variation in the oxygen isotope composition of mammalian tooth enamel: some implications for paleoclimatological and paleobiological research. Orig. Life Evol. Biosphere 29, 555-561. , 2005. Phosphine in soils, sludges, biogases and atmospheric implications-a review. Ecolog. Eng. 24, 457-463. , 2011a. Phosphate oxygen isotopes: insights into sedimentary phosphorus cycling from the Benguela upwelling system. Geochim. Cosmochim. Acta 75, 3741-3756. , 2011b. Marine sediment pore-water profiles of phosphate delta O-18 using a refined micro-extraction. Limnol. Oceanogr. Met. 9, ...
In order to investigate mid-Cretaceous terrestrial climates of low paleolatitudes, Moroccan, Tunisian and Brazilian vertebrate apatites have been analyzed for their oxygen and carbon isotope compositions of phosphates (delta O-18(p)) and carbonates (delta O-18(c), delta C-18(c)). At each site, coexisting theropod dinosaurs, titanosaurid sauropods, pterosaurs, crocodilians, turtles and fish have distinct delta O-18(p) and delta C-18(c) values reflecting their ecologies, diets and foraging environments. 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. High water temperatures ranging from 21 +/- 6 degrees C to 34 +/- 2 degrees C deduced from fish delta O-18(p) values are in agreement with those published for mid-Cretaceous low ...
Abstract: Few long and well-dated summer precipitation reconstructions that extend beyond the longest records of instrumental measurements exist in Europe. Further understanding of the past trends in summer precipitation and the mechanisms driving that variability are necessary to improve the predictions of climate models. Tree rings are unique in their ability to provide high-resolution, absolutely dated climate signals for the study of palaeoclimatology. The physiological processes controlling oxygen isotope composition (δ18O) in wood are reasonably well understood highlighting its potential as a climate proxy in a variety of environments. Significant correlation between wood δ18O and precipitation has been demonstrated worldwide reflecting both direct rainout processes and indirectly evaporative enrichment. We present an annually resolved reconstruction of precipitation based upon oxygen isotope variations in tree ring cellulose covering the most recent ˜400 years for England. The ...
Contribution of soil respiration in tropical, temperate, and boreal forests to the18O enrichment of atmospheric O2 Academic Article ...
The authors report the analysis of the oxygen isotopic composition of sulfates dissolved in 102 samples of thermal waters coming from different contexts: sedimentary (Parisian Basin), volcanic (New Mexico, West Indies, Mont Dore in France), or base (France), with t
The site-specific quantitation of N- and O-glycosylation is vital to understanding the function(s) of different glycans expressed at a given site of a protein under physiological and disease conditions. Most commonly used precursor ion intensity based quantification method is less accurate and other labeled methods are expensive and require enrichment of glycopeptides. Here, we used glycopeptide product (y and Y0) ions and (18)O-labeling of C-terminal carboxyl group as a strategy to obtain quantitative information about fold-change and relative abundance of most of the glycoforms attached to the glycopeptides. As a proof of concept, the accuracy and robustness of this targeted, relative quantification LC-MS method was demonstrated using Rituximab. Furthermore, the N-glycopeptide quantification results were compared with a biosimilar of Rituximab and validated with quantitative data obtained from 2-AB-UHPLC-FL method. We further demonstrated the intensity fold-change and relative abundance of 46 ...
The Akiri vein copper mineralization was investigated for its carbon and oxygen isotopic composition to determine the characteristics of the mineralizing fluid. Carbon and oxygen isotope analyses of Akiri siderite range between δ13C values (-1.05 to -1.71‰) and δ13O values (-14.94 to -15.18) respectively. δ13C isotopic composition is comparable to values expected for Cretaceous marine carbonates. The 18O depletion in the vein siderite indicates dominant meteoric water sources involved for carbonates precipitation. This significant depletion between the δ18O compositions of Akiri siderite compared with carbonates from other parts of the basin probably indicate differential formational temperature or fluid composition ...
Biologic rhythms give insight into normal physiology and disease. They can be used as biomarkers for neuronal degenerations. We present a diverse data set to show that hair and teeth contain an extended record of biologic rhythms, and that analysis of these tissues could yield signals of neurodegenerations. We examined hair from mummified humans from South America, extinct mammals and modern animals and people, both healthy and diseased, and teeth of hominins. We also monitored heart-rate variability, a measure of a biologic rhythm, in some living subjects and analyzed it using power spectra. The samples were examined to determine variations in stable isotope ratios along the length of the hair and across growth-lines of the enamel in teeth. We found recurring circa-annual periods of slow and fast rhythms in hydrogen isotope ratios in hair and carbon and oxygen isotope ratios in teeth. The power spectra contained slow and fast frequency power, matching, in terms of normalized frequency, the ...
Ikaite crystals incorporate ocean bottom water into their structure as they form. During cooling periods, when ice sheets are expanding, ocean bottom water accumulates heavy oxygen isotopes (oxygen 18). When glaciers melt, fresh water, enriched in light oxygen isotopes (oxygen 16), mixes with the bottom water. The scientists analyzed the ratio of the oxygen isotopes in the hydration water and in the calcium carbonate. They compared the results with climate conditions established in Northern Europe across a 2,000-year time frame. They found a direct correlation between the rise and fall of oxygen 18 in the crystals and the documented warming and cooling periods. ...
This thesis investigates how variations in the oxygen isotopic composition of lake waters in northern Fennoscandia are recorded in lake sediment archives, especially diatoms, and how these variations can be used to infer past changes in climate and atmospheric circulation. Results from analyses of the oxygen isotopic composition of lake water samples (δ18Olakew) collected between 2001 and 2006 show that δ18O of northern Fennoscandian lakes is mainly controlled by the isotopic composition of the precipitation (δ18Op). Changes in local δ18Op depend on variations in ambient air temperature and changes in atmospheric circulation that lead to changes in moisture source, vapour transport efficiency, or winter to summer precipitation distribution. This study demonstrates that the amount of isotopic variation in lake water δ18O is determined by a combination of the original δ18Olakew, the amount and timing of the snowmelt, the amount of seasonally specific precipitation and groundwater, any ...
ABSTRACT: In 2007 a ceremonial complex representing the Globular Amphora Culture was discovered in Kowal (the Kuyavia region, Poland). Radiocarbon dating demonstrated that the human remains associated with the complex are of similar antiquity, i.e. 4.105 ± 0.035 conv. and 3.990 ± 0.050 conv. Kyrs. After calibration, this suggests a period between 2850 and 2570 BC (68.2% likelihood), or more specifically, 2870 to 2500 BC (95.4% likelihood). Morphological data indicate that the skeleton belonged to a male who died at 27-35 years of age. The unusual morphology of his hard palate suggests this individual may have had a speech disorder. Stable oxygen isotope values of the individuals teeth are above the locally established oxygen isotope range of precipitation, but due to sample limitations we cannot conclusively say whether the individual is of non-local origin. Stable carbon and nitrogen isotope ratios were analyzed to reconstruct the diet of the studied individual, and show a terrestrial-based ...
You know that water is made of hydrogen and oxygen atoms arranged in molecules of H2O, but you may not be aware that there are different types of oxygen atoms. Different atoms of the same element are called isotopes. All oxygen atoms have 16 protons and 16 electrons, but some oxygen atoms have 16, 17, or 18 neutrons in the nucleus. The most abundant isotopes of oxygen in seawater are oxygen sixteen (16O) and oxygen eighteen (18O). Water molecules with 16O atoms evaporate more easily than water molecules with 18O atoms, so the relative numbers of 16O and 18O atoms that remain in the water change as evaporation occurs. Water from which 16O atoms have preferentially evaporated has a higher ratio of 18O to 16O atoms than water that has experienced less evaporation. As salinity also increases as evaporation occurs, we can generalize the relationship to state that water with an increased 18O to 16O ratio is saltier than water with a lower 18O to 16O ratio.. ! Click the red dot in the Caribbean to see ...
Euxinic conditions, which are defined by the presence of sulfide in the water column, were common in ancient oceans. However, it is not clear how the presence of sulfide in the water column affects the balance between rates of sulfide oxidation and sulfate reduction, which plays a major role in regulating the net redox state of the ocean-atmosphere system. Euxinia could lead to higher rates of sulfide oxidation because sulfide may diffuse more rapidly into the oxic zone in solution than in sediment. Alternatively, sulfide oxidation could be inhibited by low overall availability of suitable oxidants in euxinic settings. Here, we constrain rates of sulfide oxidation versus sulfate reduction in four euxinic water columns in coastal ponds by modeling the evolution of the concentration and sulfur and oxygen isotope compositions of sulfate from post-hurricane, well-oxygenated conditions to modern, euxinic conditions. The results of the one-dimensional, depth-dependent models of water column sulfate ...
Ehleringer, J.R., Bowen, G.J., Chesson, L.A., West, A.G., Podlesak, D.W. & Cerling, T.E. (2008) Hydrogen and oxygen isotope ratios in human hair are related to geography. Proceedings of the National Academy of Sciences of the United States of America, 105, 2788-2793 ...
Munich, Germany (SPX) Oct 05, 2012 - Oxygen isotopes in tree rings are an excellent archive of precipitation dynamics in the tropical Amazon region. The precise determination of the ratios of stable oxygen isotopes (18O/16O) proves to
Ng, J., B. Williams, D.M Thomson, and J. Halfar. Developing a forward model of encrusting coralline algae. Geochimica et Cosmochimica Acta, 194, 2016, 279-290.. Abstract: An increased number of climate proxy records and more refined interpretation of proxy data are crucial to improve projections of future climate at high latitudes, where internal feedbacks amplify warming and established high-resolution climate archives are especially sparse. Encrusting coralline algae are being developed as a mid- to high-latitude marine climate archive. These long-lived algae form a solid high-Mg calcite skeleton with annual growth bands similar to those of trees and tropical corals. The oxygen isotope ratio of the algal skeleton (d18Oalg) records local environmental and climatic factors, notably sea surface temperature and seawater d18O. Here we assess the d18Oalg-climate relationship in diverse environments across the algal habitat range utilizing two species of coralline algae from the genus ...
Teeth provide remarkable evidence about the early years of an individuals life. The region where a person grew up can be traced in the tooth enamel laid down in their first 14 years because strontium and oxygen isotope ratios in the teeth reflect the food a person ate and the water they drank. When rocks form, they contain minute traces of radioactive rubidium 87, which decays to strontium 87. Over millions of years, the ratio of strontium 87 to the stable isotope strontium 86 changes, so, in very young rocks, the ratio will be smaller than in very old rocks.. These rocks weather and become the soils where animals are grazed and crops grown. Some of the strontium in the soil gets into the meat and cereals produced from it and then into the teeth of the people who eat them. The strontium ratio in a persons teeth thus mirrors the strontium ratio of the geology of the area in which they spent their childhood. For example, someone who grew up in southern England would have a much lower ratio than ...
The isotope mass-balance approach was used to estimate ground-water inflow to 81 lakes in the central highlands and coastal lowlands of central Florida. The study area is characterized by a subtropical climate and numerous lakes in a mantled karst terrain. Ground-water inflow was computed using both steady-state and transient formulations of the isotope mass-balance equation. More detailed data were collected from two study lakes, including climatic, hydrologic, and isotopic (hydrogen and oxygen isotope ratio) data. For one of these lakes (Lake Starr), ground-water inflow was independently computed from a water-budget study. Climatic and isotopic data collected from the two lakes were similar even though they were in different physiographic settings about 60 miles apart. Isotopic data from all of the study lakes plotted on an evaporation trend line, which had a very similar slope to the theoretical slope computed for Lake Starr. These similarities suggest that data collected from the detailed ...
Roden, J & Farquhar, G 2012, A controlled test of the dual-isotope approach for the interpretation of stable carbon and oxygen isotope ratio variation in tree rings, Tree Physiology, vol. 32, no. 4, pp. 490-503. ...
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Knowledge and management of aquatic ecosystems (formerly Bulletin Français de la Pèche et de la Pisciculture), an international journal on freshwater ecosystem
Whole-plant 13C discrimination, Δ13Cp, showed a strong correlation with instantaneous measurements of ci/ca (Fig. 7), suggesting that in general Δ13Cp was a faithful recorder of ci/ca, as predicted by Equation 6. The mean value for d that we estimated for the full data set was 3.1‰, reasonably similar to a value of 4.0‰, recently estimated for Ficus insipida (Cernusak et al., 2007b). The Δ13Cp was also a reasonably good predictor of variation in TEc, Dg·TEc, and vg·TEc (Table VI). We previously observed that the relationship between Δ13Cp and TEc broke down at the species level, appearing to reflect species-specific offsets in the relationship between the two parameters (Cernusak et al., 2007a). Whereas there was some evidence of similar behavior in this study, as can be seen in Figure 8, the species-level relationship between Δ13Cp and Dg·TEc was generally much stronger in this study. For example, in a least-squares linear regression between Δ13Cp and Dg·TEc using species means, ...
palindrom (#27 on the WUWT article)- Im doing my graduate work in the area of oxygen isotope paleothermometry (which I do think has a lot of advantage over dendroclimatology), so Ill just say a few general things, but I dont plan on reading the WUWT article in enough depth to disentangle it piece by piece (note for people who reply that Id rather continue this in the April Open Thread since it is OT and this thread is still young).. First, I do think that there is a lot of work to be done in the interpretation of oxygen/hydrogen isotope values obtained at a site, and theres still plenty of disagreement in the paleo-community on how to best connect the isotopic signal in a record with climate. However, there are also many well understood thermodynamic, physical principles at play. There are also a number of paleoclimatic recorders of oxygen isotopes, including lake/ocean records, speleothems (in caves), corals, ice cores, etc. The factors and caveats that impact all of these different ...
This work projects photoluminescence (PL) as an alternative technique to estimate the order of resistivity of zinc oxide (ZnO) thin films. ZnO thin films, deposited using chemical spray pyrolysis (CSP) by varying the deposition parameters like solvent, spray rate, pH of precursor, and so forth, have been used for this study. Variation in the deposition conditions has tremendous impact on the luminescence properties as well as resistivity. Two emissions could be recorded for all samples-the near band edge emission (NBE) at 380 nm and the deep level emission (DLE) at ∼500 nm which are competing in nature. It is observed that the ratio of intensities of DLE to NBE (DLE/NBE) can be reduced by controlling oxygen incorporation in the sample. - measurements indicate that restricting oxygen incorporation reduces resistivity considerably. Variation of DLE/NBE and resistivity for samples prepared under different deposition conditions is similar in nature. DLE/NBE was always less than resistivity by an ...
Ocean anoxic events were periods of high carbon burial that led to drawdown of atmospheric carbon dioxide, lowering of bottom-water oxygen concentrations and, in many cases, significant biological extinction (Arthur et al., 1990; Erbacher et al., 1996, doi:10.1130/0091-7613(1996)0242.3.CO;2; Kuypers et al., 1999, doi:10.1038/20659; Jenkyns, 1997; Hochuli et al., 1999, doi:10.1130/0091-7613(1999)0272.3.CO;2). Most ocean anoxic events are thought to be caused by high productivity and export of carbon from surface waters which is then preserved in organic-rich sediments, known as black shales. But the factors that triggered some of these events remain uncertain. Here we present stable isotope data from a mid-Cretaceous ocean anoxic event that occurred 112 Myr ago, and that point to increased thermohaline stratification as the probable cause. Ocean anoxic event 1b is associated with an increase in surface-water temperatures and runoff that led to decreased bottom-water formation and elevated carbon ...
Anderson, Lesleigh, 1999, Holocene paleoclimatology of northern Alaska from oxygen isotope geochemistry of sediment cellulose and authigenic carbonate in lake sediments: University of Massachusetts, Amherst, M.S. thesis, 139 p., illust., maps.. ...
François Fourel, Francois Martineau, Emoke Toth, Agnes Görög, Gilles Escarguel, et al.. Carbon and oxygen isotope variability among foraminifera and ostracod carbonated shells. Physica, 2015, 70, pp.133-156. ⟨10.17951/aaa.2015.70.133⟩. ⟨hal-02334191⟩ ...
Johnsen, S. J. , Dahl-Jensen, D. , Gundestrup, N. , Steffensen, J. P. , Clausen, H. B. , Miller, H. , Masson-Delmotte, V. , Sveinbjörnsdottir, A. E. and White, J. (2001): Oxygen isotope and palaeotemperature records from six Greenland ice-core stations: Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP , Journal of Quaternary Science ...
Basak, C, Rathburn, T, Pérez, E et al 2009, Carbon and oxygen isotope geochemistry of live (stained) benthic foraminifera from the Aleutian Margin and the Southern Australian Margin, Marine Micropaleontology, vol. 70, pp. 89-101. ...
The oxygen isotopic composition of vertebrate bone phosphate (δp) is related to ingested water and to the body temperature at which the bone forms. The δp is in equilibrium with the individuals body water, which is at a physiological steady state throughout the body. Therefore, intrabone temperature variation and the mean interbone temperature differences of well-preserved fossil vertebrates can be determined from the δp variation. Values of δp from a well-preserved Tyrannosaurus rex suggest that this species maintained homeothermy with less than 4°C of variability in body temperature. Maintenance of homeothermy implies a relatively high metabolic rate that is similar to that of endotherms. ...
The oxygen isotope ratio of dissolved inorganic phosphate (δ18Op) represents a novel and potentially powerful stable isotope tracer for biogeochemical research. Analysis of δ18Op may offer new insights into the relative importance of different sources of phosphorus within natural ecosystems. Due to the isotope fractionations that occur alongside metabolism of phosphorus-containing compounds, δ18Op could also be used to better understand the intracellular and extracellular reaction mechanisms that control phosphorus cycling. In this thesis, new methods were developed and tested for the extraction of dissolved inorganic phosphate (Pi) from freshwaters and its isolation from other oxygen-containing compounds, including nitrate, sulfate and dissolved organic matter. Excluding contaminant sources of oxygen during δ18Op analysis is a critical analytical challenge that has constrained δ18Op research in freshwaters to date. These new methods were evaluated against existing protocols for analysis of ...
We have a strong theoretical, computational, experimental, and observational establishment in geochemistry. Research interest encompasses high-dimensional stable isotope fractionation, atmospheric chemistry, martian surface processes, early Earth, impacts, the Great Oxidation Event, snowball Earth, Paleozoic Earth climate, coupled mountain-building and climate change, coupled evolution of life and environment, paleoceanography, cryosphere geochemistry, property of man-made materials, and isotope equilibrium and kinetics. The department has fully equipped wet-chemistry laboratories, trace-element laboratory, organic geochemistry laboratory, and state-of-art stable isotope facilities that have the unique capability including analyzing triple oxygen isotope compositions of diverse compounds, and first-principles atomistic modeling with access to high-performance computers on campus. Faculty members ...
This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy profiles and pasture (grasses and shrubs) as well as corresponding carbon and nitrogen tissue concentrations in a number of different sites across Brazil. The sampling design captured the temporal variation in rainfall over the course of several years. Carbon and nitrogen isotope ratios can act as a proxy for interpreting aspects of the carbon and nitrogen cycles in Amazonian rainforests. Data are in three comma-delimited ASCII files. ...
...A new study of the High Arctic climate roughly 50 million years ago le...The new study which looked at temperatures during the early Eocene pe...The team used a combination of oxygen isotope ratios from fossil bone ...The team concluded the average temperatures of the warmest month on El...,New,study,shows,how,giant,tortoises,,alligators,thrived,in,High,Arctic,50,million,years,ago,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
Moon formed of mostly Earths mantle debris, which explains the compositional similarities, especially the similar Oxygen isotope ratios. There are still lingering questions, but it does the best so far at explaining the observed properties of the Moon ...
The [delta]13rmC of CH4 emitted from the tropical Amazon river floodplain, temperate peat bogs in Washington and Minnesota, and the arctic Alaskan tundra was 59, 73, 66, and 65‰, respectively. The [delta]D of CH4 from these sites was 294, 308, 339, and 391‰, respectively, and a linear relationship was observed between the [delta]D of CH4 and soil water. A 13C balance between CH4, CO2, and soil organic matter indicated a higher percentage of CH4 production via methyl conversion at the Amazon floodplain than at the other wetland sites and that the anoxic CO2 flux was 1.5 to 2.0 times the CH4 flux. The 13C balance provided greater constraint on the anoxic CO2 flux than calculations based on soil water gradients. An in situ value of 0.774 for the hydrogen kinetic isotope effect during microbial CH4 oxidation was estimated from the increase in the [delta]13rmC of CH4 and [delta]D of CH4 in flux samples from the Amazon site. The average [delta]13rmC of CH4 released from an acidic peat bog in ...
Mauna Loa, Hawaii and Sunnyvale, CA, USA - Climate scientists from the University of Colorado and the University of New Mexico studying the water cycle have successfully deployed a Picarro precision water isotope analyzer at a remote monitoring station near the top of Mauna Loa, Hawaii. Sampling water vapor at this extreme altitude (11,000 feet above sea level) is notoriously difficult because the water concentration can drop as low a few hundred parts per million. Yet the Picarro G1102-i, which utilizes WS-CRDS (wavelength scanned cavity ring down spectroscopy), is directly sampling the outside air at this location and providing simultaneous measurement of both δD and δ18O every ten seconds. The absolute calibration is checked with liquid water standards every few hours, which confirms that the instrument has virtually no drift over a six day period. During this extended period the standard deviation of all measurements has been 0.650/00 for δD and 0.080/00 for δ18O - levels of absolute ...
Knowledge and management of aquatic ecosystems (formerly Bulletin Français de la Pèche et de la Pisciculture), an international journal on freshwater ecosystem
Models for the growth of continental crust rely on knowing the balance between the generation of new crust and the reworking of old crust throughout Earths history. The oxygen isotopic composition of zircons, for which uranium-lead and hafnium isotopic data provide age constraints, is a key archive of crustal reworking. We identified systematic variations in hafnium and oxygen isotopes in zircons of different ages that reveal the relative proportions of reworked crust and of new crust through time. Growth of continental crust appears to have been a continuous process, albeit at variable rates. A marked decrease in the rate of crustal growth at ~3 billion years ago may be linked to the onset of subduction-driven plate tectonics.. ...
TY - JOUR. T1 - Vertical sheep mobility along the altitudinal gradient through stable isotope analyses in tooth molar bioapatite, meteoric water and pastures: A reference from the Ebro valley to the Central Pyrenees. AU - Tornero, Carlos. AU - Aguilera, Mónica. AU - Ferrio, Juan Pedro. AU - Arcusa, Héctor. AU - Moreno-García, Marta. AU - Garcia-Reig, Sheila. AU - Rojo-Guerra, Manuel. PY - 2018/8/10. Y1 - 2018/8/10. N2 - © 2016 Elsevier Ltd and INQUA Although the frequency of pastoral activities involving vertical sheep mobility has decreased over the last century, this is a herding strategy still used in the Ebro basin, where animals move from overwintering valley locations up to the Pyrenees from late spring to early autumn. Such practice allows herders to avoid the worst climatic conditions, seasonally balancing the great contrast between ecological zones in this region, from dry lowland Mediterranean steppe to wet mountain subalpine grasslands. As recent regional archaeological works have ...
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Many studies of climate variability in the Tropical Ocean have used high-resolution chemical tracer records contained in coral skeletons. The complex architecture of coral skeletons may lead to the possibility of biases in coral records and it is therefore important to access the fidelity of coral geochemical records as environmental proxies. Coral skeletal records from the same coral colony, and even the same corallite, may show large variation due to differing extension rates, formational timing of the skeletal elements, colony topography, and sampling resolution. To assess the robustness of the skeletal record, we present d13C and d18O data based on different sampling resolutions, skeletal elements, and coral colonies of Montastraea faveolata species complex, the primary coral used for climate reconstruction in the Atlantic. We show that various skeletal elements produce different isotopic records. The best sampling rate to resolve the full annual range of sea surface temperature (SST) is 40 ...
A new study published in Science suggests that the great predators of Mesozoic seas, the plesiosaurs, icthyosaurs, and mosasaurs, maintained an average body temperature around 100 degrees Fahrenheit. This conclusion was achieved by studying the oxygen isotopes in their teeth; fish from the mesozoic and today - all cold-blooded, of course - show variation in their oxygen isotopes based on the temperature of water they live in. The marine reptiles of the Mesozoic dont show this variation. No matter what temperature water they lived in, they maintained a constant temperature and thus can be assumed to have been active predators adept at cornering the apex predator niche in all sorts of marine environments ...
The irons display a range in values which is to too large to be the result of fractionation processes in the nebula. An explanation involving primordial heterogeneity is favoured, with the iron meteorite parent bodies having sampled at least four isotopically distinct nitrogen reservoirs. One of the factors controlling the variation may be an input of 1%-rich nitrogen, together with 26Al, from a nova event prior to solar nebula collapse. The behaviour of nitrogen during core formation processes is also considered and compared with the observed nitrogen variation in the non-magmatic group lAB. Other secondary processes affecting nitrogen in the iron meteorites are also identified. The isotopic composition of nitrogen has been used to identify genetic links between iron and stony meteorites, thereby enhancing the normal technique based on oxygen isotopic composition (prohibited by the rarity of oxygen bearing minerals ...
The complex between 17O-enriched DOTA (tetraazacyclododecanetetraacetic acid) and praseodymium(iii) (Pr3+) was studied in aqueous solution by variable-temperature 17O NMR at 14.1 T. pH effects as well as the influence of metal ions free in solution were investigated. At low temperature, the so-called TSAP an
Laboratory experiments with stable isotopes (13C and 15N) were conducted to determine the importance of bacteria and algae as food sources for free-living nematodes. All tested bacterivorous nematodes (Caenorhabditis elegans, Acrobeloides tricornis, Poikilolaimus sp. and Panagrolaimus sp.) were found to be depleted in δ13C (on average by −1.71 ± 0.56‰) and enriched in δ15N (on average by 3.17 ± 1.27‰) relative to their bacterial diets of Escherichia coli and Matsuebacter sp. The nematode species showed considerable differences in their stable isotope composition with respect to food sources. Moreover, they differed significantly in δ13C and δ15N values when placed on the same bacterial diet of E. coli, consistent with differences in their trophic shifts. Conversely, no differences in δ13C values were observed among nematode species placed on the same Matsuebacter sp. diet. In mixed food sources of E. coli and Matsuebacter sp., E. coli contributed 71% of the carbon to C. elegans and
1. Mitchell P. Coupling of phosphorylation to electron and hydrogen transfer by a chemiosmotic type of mechanism. Nature. 1961;191:144-8 2. Brand MD. The stoichiometry of proton pumping and ATP synthesis in mitochondria. The Biochemist. 1994;16:20-4 3. Chance B, Williams GR. The Respiratory Chain and Oxidative Phosphorylation. Adv Enzymol Relat Subj Biochem. 1956;17:65-134 4. Berg JM, Tymoczko JL, Stryer L. The rate of oxidative phosphorylation is determined by the need for ATP. Biochemistry, 5thEdition. New York, USA: Freeman WH & Co. 2002:552 5. Boyer PD, Cross RL, Momsen W. A new concept for energy coupling in oxidative phosphorylation based on a molecular explanation of the oxygen exchange reactions. Proc Natl Acad Sci USA. 1973;70:2837-39 6. Kayalar C, Rosing J, Boyer PD. An alternating site sequence for oxidative phosphorylation suggested by measurement of substrate binding patterns and exchange reaction inhibitions. J Biol Chem. 1977;252:2486-91 7. Milgrom YM, Cross RL. ...
Rugby League is a high-intensity collision sport competed over 80 min. Training loads are monitored to maximize recovery and assist in the design of nutritional strategies although no data are available on the total energy expenditure (TEE) of players. We therefore assessed resting metabolic rate (RMR) and TEE in six Super League players over 2 consecutive weeks in-season including one game per week. Fasted RMR was assessed followed by a baseline urine sample before oral administration of a bolus dose of hydrogen (deuterium 2H) and oxygen (18O) stable isotopes in the form of water (2H2 18O). Every 24 hr thereafter, players provided urine for analysis of TEE via DLW method. Individual training load was quantified using session rating of perceived exertion (sRPE) and data were analyzed using magnitude-based inferences. There were unclear differences in RMR between forwards and backs (7.7 ± 0.5 cf. 8.0 ± 0.3 MJ, respectively). Indirect calorimetry produced RMR values most likely lower than ...
The identical oxygen isotopic composition of Earth and Moon might be explained by exchange of material between the proto-Earth and the surrounding proto-lunar disk: Planetary Science Research Discoveries (PSRD) educational on-line space science magazine.
The linearity of the assays run with D2O and H218O are quite remarkable. The decrease in speed for the D2O assay is about 21% and the decrease in the H218 assay is about 5%. The viscosity of D2O is about 20% greater than H2O while H218 is 5% greater than H2O. The speed differences measured would suggest in light of the viscosity numbers that we measured a viscous change in the solvent and not an osmotic pressure change. These results are quite remarkable as they indicate that gliding motility speeds can measure small viscous changes in solutions. Kotyk et. al. (Kotyk 1990) showed that ATP activity was not affected by the addition of D2O using yeast as the test subject. Our data would suggest that ATP activity of kinesin is also not affected by the addition of D2O. If ATP activity was hindered by the addition of D2O then I would have expected to see slower speeds than what I measured using D2O because clearly, there is a viscous affect and anything lower than what I measured would indicate that ...
Burkhardt, C., Dauphas, N., Tang, H., Fischer-Gödde, M., Qin, L., Chen, J. H., Rout, S. S., Pack, A., Heck, P. R. and Papanastassiou, D. A.. Meteoritics & Planetary Science. doi: 10.1111/maps.12834. LINK. High-precision isotope data of meteorites show that the long-standing notion of a chondritic uniform reservoir is not always applicable for describing the isotopic composition of the bulk Earth and other planetary bodies. To mitigate the effects of this isotopic crisis and to better understand the genetic relations of meteorites and the Earth-forming reservoir, we performed a comprehensive petrographic, elemental, and multi-isotopic (O, Ca, Ti, Cr, Ni, Mo, Ru, and W) study of the ungrouped achondrites NWA 5363 and NWA 5400, for both of which terrestrial O isotope signatures were previously reported. Also, we obtained isotope data for the chondrites Pillistfer (EL6), Allegan (H6), and Allende (CV3), and compiled available anomaly data for undifferentiated and differentiated meteorites. The ...
HONKON Facial Cleaning Acne Removal Water Oxygen Jet Peel Beauty Machine For SaleTreatment TheoryWater and Oxygen Jet is an effective acne treatment system, which mixes water,medical oxygen and nutrition liquid sufficien...
source of synonymy Beu A.G. 2006. Marine Mollusca of oxygen isotope stages of the last 2 million years in New Zealand. Part 2. Biostratigraphically useful and new Pliocene to recent bivalves. Journal of the Royal Society of New Zealand, 36(4): 151-338 ...
John, Take a look at the analysis of the Oxygen Isotopes of the three burials that were excavated consisting of an adult woman and two children. For the life of me I cannot remember the place but it featured on Meet the Ancestors and had teh biggest hole I have ever seen in Archaeology. Th eisotope analysis showed the woman and children to have walked a considerable distance Rob http://acorngenealogy.co.uk http://www.enchantedtimes.co.uk ----- Original Message ----- From: John Wood ,[log in to unmask], To: ,[log in to unmask], Sent: Monday, July 17, 2006 11:17 AM Subject: Re: [BRITARCH] Heritage & carbon emissions ,,,Kevin Tolley ,[log in to unmask], wrote: , , As such, if Stonehenge were a place to , visit, then why shouldnt people from distant places , visit? ,,, , , No doubt people from some distance would have visited Stonehenge but what , concerns me is the numbers along with the distances. , , Trades people no doubt moved about the countryside trading goods and , hence we get a spread ...
This data set consists of CO2 concentrations from oxygen isotopes in air trapped in the Taylor Dome (Antarctica) ice core from 20 to 60 kyr BP. The data set consists of depth (m), ice age (kyr BP ... ...
Using reconstructed unconformity-bounded stratigraphy, the geological evolution of Panarea and surrounding islets can be described in terms of the interaction between the growing volcano and sea-level fluctuations. From the recognition of marine deposits corresponding to marine oxygen isotope stage (MIS) 5 and of widespread Brown Tuff-type pyroclastic deposits on Panarea, two first-order unconformities (UI and UII) of regional stratigraphic significance can be correlated with the island of Lipari and adopted as a means of correlation on an inter-island scale in the Aeolian Volcanic District. Then, two second-order and three third-order unconfomities, consisting of erosional surfaces related to minor sea-level fluctuations or to subaerial reworking operating during the phases of volcanic inactivity, are introduced. The construction of the volcanic edifice occurred during seven successive eruptive epochs of local volcanic activity, between 150 and 10 ka, with intervening dormant periods ...
Affiliation:名古屋大学,環境学研究科,准教授, Research Field:Environmental dynamic analysis,Meteorology/Physical oceanography/Hydrology,Environmental dynamic analysis, Keywords:大気化学,化学輸送モデル,大気酸化能,対流圏オゾン,エアロゾル,化学気候モデル,大気汚染,メタン,成層圏オゾン,気候変動, # of Research Projects:7, # of Research Products:120, Ongoing Project:Quantifying nitrate dynamics in hydrosphere using triple oxygen isotopes as tracers
In most current designs of D-T fusion reactor blankets employing ceramic breeder materials, the use of a helium sweep gas containing 0.1 % of hydrogen is contemplated to extract tritium efficiently via isotopic exchange reactions. However, the isotope exchange reaction proceeds fast only at the more elevated temperatures, so that the rate of isotope exchange reactions is considerably low at lower temperatures. Taking into consideration that there is a broad temperature distribution within a blanket module, it is anticipated that the tritium bred in regions of lower temperatures will be poorly recovered. For this reason, there is still a need to develop techniques that contribute to the acceleration of the recovery of bred tritium at lower temperatures. In our previous works, the effect of catalytic active metal additives, such as Pt and Pd, on the heterogeneous isotope exchange reactions at the breeder-sweep gas interface was examined. The results indicate that the exchange reactions were ...
A mononuclear side-on peroxocobalt(III) complex with a tetradentate macrocyclic ligand, [CoIII(TBDAP)(O2)]+ (1), shows a novel and facile mode of dioxygenase-like reactivity with nitriles (R - C=N; R = Me, Et, and Ph) to produce the corresponding mononuclear hydroximatocobalt(III) complexes, [CoIII(TBDAP)(R - C(=NO)O)]+, in which the nitrile moiety is oxidized by two oxygen atoms of the peroxo group. The overall reaction proceeds in one-pot under ambient conditions (ca. 1 h, 40 °C). 18O-Labeling experiments confirm that both oxygen atoms are derived from the peroxo ligand. The structures of all products, hydroximatocobalt(III) complexes, were confirmed by X-ray crystallography and various spectroscopic techniques. Kinetic studies including the Hammett analysis and isotope labeling experiments suggest that the mechanistic mode of 1 for activation of nitriles occurs via a concerted mechanism. This novel reaction would be significantly valuable for expanding the chemistry for nitrile activation ...
Objectives. To assess the environmental impacts of handling, storage and field application of fermentates as influenced by the carbon and nutrient pools defined in WP3.. Method. A pilot-scale storage facility will be used to determine GHG and NH3 emission factors for selected fermentates; this will be planned and conducted in collaboration with ATB. As input for improved models of N2O emissions and carbon storage after field application, a mesocosm will be designed. It will allow fermentate to be added to soil at well-defined matric potential. Experiments with fermentates from a large variety of different biomasses, digested. using different retention times and temperatures, will be carried out. Interactions with soil type and water content will be studied. Fluxes of CH4, N2O and CO2 will be measured using gas chromatography, and fluxes of NH3 using an INNOVA photo-acoustic analyser. Sources of N2O will be studied using an LGR N2O isotope analyser. In order to determine the influence of ...
My research is focused on the ubiquitous presence of saline fluids at depth in the continental crust, either in sedimentary systems or within crystalline basement in fracture controlled systems. How did these fluids gain their actual salinities, which can be up to 10 times the modern seawater salinity? What is the time scale in which this deep reservoir of the hydrosphere exchanges with surface reservoir such as the oceans or more diluted shallower groundwaters? Conservative chlorine and bromine stable isotopes (respectively 37Cl/35Cl and 81Br/79Br) can be used as source tracers to identify mixing in this kind of fluids. Furthermore they have been used to identify processes at the origin of the salinity or to constrain diffusion in low permeability environments. Im also focusing on classic water isotope composition (18O and 2H) to assess the extent of water-rock interaction and its relation to the generation of abiogenic reduced gas such as CH4 or H2 in the Canadian Shield ...
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The catalytic mechanism of intra and extra catechol cleaving dioxygenases is still a matter of debate, because the intermediate transient oxygen adduct has never been isolated in these enzymes. The complex [(triphos)Ir(dtbc)]+ (triphos=MeC(CH2PPh2)3, DBTC2−=3,5-di-tert-butylcatecholate), reacts with molecular oxygen and exhibits a ring-cleaving catalytic activity, and a stable oxygen intermediate appears; this stimulates an opportunity for obtaining information that can be transferable to the above-mentioned enzymatic catalytic centers, therefore, giving a breakthrough into the strategy of oxygen activation in these natural systems. Here, we present the results of our computational approach, based on density functional theory, focusing on the following aspects: to explain the interaction with molecular oxygen and how to avoid the existing spin problem, to understand the formation of the bridging moiety, to clarify, if any, the possible influence on the structure of the formed adduct of the ...
TY - JOUR. T1 - Properties of and oxygen binding by albumin-tetraphenylporphyrinatoiron(II) derivative complexes. AU - Tsuchida, Eishun. AU - Ando, Katsutoshi. AU - Maejima, Hiromitsu. AU - Kawai, Noriyuki. AU - Komatsu, Teruyuki. AU - Takeoka, Shinji. AU - Nishide, Hiroyuki. PY - 1997/7/1. Y1 - 1997/7/1. N2 - A hydrophobic tetraphenylporphyrinatoiron(II) derivative bearing a covalently bound axial imidazole [Fe(II)P] was efficiently and noncovalently bound into human serum albumin (HSA) up to an average of eight Fe(II)P molecules per HSA molecule. The aqueous solutions of the HSA-Fe(II)P complex provided a reversible and relatively stable oxygen adduct under physiological conditions (pH 7.4 and 37 °C). The half-life of the oxygen adduct (τ( 1/4 )) was 1 h at 37 °C in an air atmosphere. With Fe(II)-TpivPP (the so-called picket-fence heme) having no axial base, an oxygenated HSA-Fe(II)TpivPP complex was obtained using a 20-fold molar excess of 1,2-dimethylimidazole, but the τ( 1/4 ) was ...
Altabet, Mark A; Francois, Roger (2003): Natural nitrogen and carbon stable isotopic composition of station NBP97-03-04-5. PANGAEA, https://doi.org/10.1594/PANGAEA.128236
Altabet, Mark A; Francois, Roger (2003): Natural nitrogen and carbon stable isotopic composition of station NBP96-04-06-4. PANGAEA, https://doi.org/10.1594/PANGAEA.128214
"Oxygen - Isotopes and Hydrology". SAHRA. Archived from the original on 2 January 2007. Retrieved 10 September 2007.. ... Isotopes of hydrogen Complete table of nuclides. Deuterium (or hydrogen-2, symbol 2. H. or D. , also known as heavy hydrogen) ... The heavy isotopes of hydrogen and oxygen in rainwater (so-called meteoric water) are enriched as a function of the ... Measurements of small variations in the natural abundances of deuterium, along with those of the stable heavy oxygen isotopes ...
CS1 maint: discouraged parameter (link) Valley, John W. (Jan 2003). "Oxygen Isotopes in Zircon". Reviews in Mineralogy and ... CS1 maint: discouraged parameter (link) Kinny, Peter D.; Maas, Roland (Jan 2003). "Lu-Hf and Sm-Nd isotope systems in zircon". ... Zircon is also useful because its incorporation of other elements like uranium, lutetium, samarium, and oxygen can be analyzed ... Slow diffusion rates also prevent contamination by leaking or loss of isotopes from the crystal, increasing the likelihood that ...
Oxygen isotope ratios in fossilized bone are sometimes used to determine the temperature at which the bone was deposited, as ... Barrick, R. E.; Stoskopf, M. K.; Showers, W. J. (1999). "Oxygen isotopes in dinosaur bones". In Farlow, J. O.; Brett-Surman, M ... Other scientists have pointed out that the ratio of oxygen isotopes in the fossils today does not necessarily represent the ... Trueman, C.; Chenery, C.; Eberth, D. A.; Spiro, B. (2003). "Diagenetic effects on the oxygen isotope composition of bones of ...
Isotopes of oxygen Dole, Malcolm (1936). "The Relative Atomic Weight of Oxygen in Water and in Air". Journal of Chemical ... The Dole effect, named after Malcolm Dole, describes an inequality in the ratio of the heavy isotope 18O (a "standard" oxygen ... 1989). "Differential fractionation of oxygen isotopes by cyanide-resistant and cyanide-sensitive respiration in plants". Planta ... Morita, N. (1935). "The increased density of air oxygen relative to water oxygen". J. Chem. Soc. Japan. 56: 1291. Kroopnick, P ...
They studied variations in the ratio of oxygen-17 and oxygen-18 to the most abundant isotope oxygen-16, building on their ... Clayton worked in the field of cosmochemistry and is best known for the use of the stable isotopes of oxygen to classify ... Clayton and Mayeda studied the Achondrite meteorites and showed that variations in the oxygen isotope ratios within a planet ... Clayton, Robert N.; Onuma, Naoki; Mayeda, Toshiko K. (1976-04-01). "A classification of meteorites based on oxygen isotopes". ...
Wiechert, U.; Halliday, A. N.; Lee, D.-C.; Snyder, G. A.; Taylor, L. A.; Rumble, D. (October 2001). "Oxygen Isotopes and the ... "Oxygen Isotopes Give Clues to the Formation of Planets, Moons, and Asteroids". Planetary Science Research Discoveries Report: ... this hypothesis does not adequately explain the essentially identical oxygen isotope ratios of the two bodies.[4] ... This collision also resulted in the 23.5° tilted axis of the Earth, thus causing the seasons.[1] The Moon's oxygen isotopic ...
Heavy-oxygen water[edit]. Water enriched in the heavier oxygen isotopes 17. O and 18. O is also commercially available, e.g., ... while those of oxygen-16 and oxygen-17 are 0.19 and 0.24 millibarns, respectively. 17O makes up 0.038% of natural oxygen, ... Mosin, O. V, Ignatov, I. (2011) Separation of Heavy Isotopes Deuterium (D) and Tritium (T) and Oxygen (18O) in Water Treatment ... Therefore, in D2O with natural oxygen, 21% of neutron captures are on oxygen, rising higher as 17O builds up from neutron ...
In the 1990s, in addition to continued work on radiocarbon calibration and solar variability, he began work on oxygen isotopes ... Stuiver, M. and P. M. Grootes (2000). "GISP2 oxygen isotope ratios." Quaternary Research 53(3): 277-283. Personal communication ... There he built the Quaternary Isotope Lab with a lead-lined room 30 feet below ground to shield the hand-built gas counters ... Their sub-annual resolution stable isotopes measurements provided confirmation of the rapid nature of major climatic changes at ...
Oxygen isotopes in dinosaur bones. (編) James O. Farlow and M. K. Brett-Surman. The Complete Dinosaur. Bloomington: Indiana ... Thermophysiology of Tyrannosaurus rex: Evidence from Oxygen Isotopes. Science (New York City). July 1994, 265 (5169): 222-224 [ ... Diagenetic effects on the oxygen isotope composition of bones of dinosaurs and other vertebrates recovered from terrestrial and ...
Karhu, J.A.; Holland, H.D. (1 October 1996). "Carbon isotopes and the rise of atmospheric oxygen". Geology. 24 (10): 867-870. ... Oxygen only began to persist in the atmosphere in small quantities about 50 million years before the start of the Great ... Oxygen is a reactive compound, and should eventually combine with gases and minerals of the Earth's atmosphere and crust. ... Traces of methane (at an amount of 100,000 tonnes produced per year) should not exist, as methane is combustible in an oxygen ...
"Oxygen isotopes and emerald trade routes since antiquity". Science. 287 (5453): 631-633. Bibcode:2000Sci...287..631G. doi: ...
Oxygen isotope ratio in atmosphere varies predictably with time of year and geographic location; e.g. there is a 2% difference ... Different oxygen isotopic signatures can indicate the origin of material ejected into space. The Moon's titanium isotope ratio ... The rate of exchange of surface isotopes with the environment has to be taken in account. The oxygen isotopic signatures of ... October 2001). "Oxygen Isotopes and the Moon-Forming Giant Impact". Science. 294 (12): 345-348. Bibcode:2001Sci...294..345W. ...
October 2001). "Oxygen Isotopes and the Moon-Forming Giant Impact". Science. 294 (12): 345-348. Bibcode:2001Sci...294..345W. ... Scott, Edward R. D. (December 3, 2001). "Oxygen Isotopes Give Clues to the Formation of Planets, Moons, and Asteroids". ... The Moon's oxygen isotopic ratios are essentially identical to those of Earth. Oxygen isotopic ratios, which may be measured ... which show oxygen isotope ratios nearly identical to those of Earth. The highly anorthositic composition of the lunar crust, as ...
As oxygen isotopes (18O and 16O) and hydrogen isotopes (2H and 1H) have different masses, they behave differently in the ... describes the global annual average relationship between hydrogen and oxygen isotope (Oxygen-18 and Deuterium) ratios in ... Gat, J. R. (1996). "Oxygen and hydrogen isotopes in the hydrologic cycle". Annual Review of Earth and Planetary Sciences. 24 (1 ... The relationship of δ18O and δ2H in meteoric water is caused by mass dependent fractionation of oxygen and hydrogen isotopes ...
October 2001). "Oxygen Isotopes and the Moon-Forming Giant Impact". Science. 294 (12): 345-348. Bibcode:2001Sci...294..345W. ... Other bodies of the inner Solar System such as Mars and Vesta have, according to meteorites from them, very different oxygen ... This age is calculated from isotope dating of lunar zircons. More accurately, the Moon's mean sidereal period (fixed star to ... Other Apollo lunar samples had in 2012 the same titanium isotopes composition as Earth, which conflicts with what is expected ...
"Oxygen Isotopes and the Moon-Forming Giant Impact". Science. 294 (12): 345-348. Bibcode:2001Sci...294..345W. doi:10.1126/ ... A torus of oxygen and hydrogen produced by Saturn's moon, Enceladus forms part of the E ring around Saturn. Nitrogen gas ... The Io plasma torus is a transfer of oxygen and sulfur from the tenuous atmosphere of Jupiter's volcanic moon, Io and other ... In the case of the latter, however, virtually identical isotope ratios found in samples of the Earth and Moon cannot be ...
Evidence from Oxygen Isotopes". Science. New York City. 265 (5169): 222-224. Bibcode:1994Sci...265..222B. doi:10.1126/science. ...
64: 1315-1326, 1953). (See Oxygen isotope ratio cycle.) He retired from the university in 1972 but continued to write and run ... He worked closely with Harold Urey to find a way to use the ratio of oxygen isotopes to determine temperatures in previous eras ...
2001). "Oxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high δ18O ... 2006). Oxygen isotopes, REE and U-Pb behaviour during metamorphic zircon formation. Geochimica Et Cosmochimica Acta, 70(18), ... Highly precise in situ SIMS measurements of oxygen isotopes and OH/O ratios, laser-ablation inductively-coupled mass ... Valley JW, Chiarenzelli JR, McLelland JM (1994). "Oxygen isotope geochemistry of zircon". Earth and Planetary Science Letters ...
Oxygen has three stable isotopes, and 14 unstable ones. Sulfur has four stable isotopes, 20 radioactive ones, and one isomer. ... Human blood contains a large amount of oxygen. Human bones contain 28% oxygen. Human tissue contains 16% oxygen. A typical 70- ... Isotopes[edit]. Out of the six known chalcogens, one (oxygen) has an atomic number equal to a nuclear magic number, which means ... of all oxygen produced goes to this application. The chemical industry also uses large amounts of oxygen; 25% of all oxygen ...
... see oxygen isotope ratio cycle). Seawater molecules that contain the lighter isotope, oxygen-16, evaporate at a slightly faster ... The number of neutrons varies according to the isotope: the stable isotopes have 8, 9, or 10 neutrons. Oxygen is a member of ... Oxygen, as a mild euphoric, has a history of recreational use in oxygen bars and in sports. Oxygen bars are establishments ... Oxygen tents were once commonly used in oxygen supplementation, but have since been replaced mostly by the use of oxygen masks ...
Oxygen isotopes: δ18O 2.569 ‰, δ17O 1.179 ‰, ∆1 7O = −0.157 ‰. A section weighing 31 kilograms (68 lb; 4.9 st) of type specimen ...
"Oxygen Isotopes and Emerald Trade Routes Since Antiquity" (PDF). Science. 287 (5453): 631-3. Bibcode:2000Sci...287..631G. doi: ...
"Oxygen Isotopes and Emerald Trade Routes Since Antiquity" (PDF). Science. 287 (5453): 631-3. Bibcode:2000Sci...287..631G. doi: ...
"Stable Hydrogen and Oxygen Isotopes in the Water Cycle". In Jäger, E.; Hunziker, J.C. (eds.). Lectures in Isotope Geology. ... "Isotopes of Hydrogen". Introduction to Chemistry. 26 September 2016. Archived from the original on 31 March 2020. Retrieved 13 ... Deuterium is a naturally-occurring, stable (non-radioactive) isotope of hydrogen with a nucleus consisting of a single proton ... I'll stick to tap water, thank you." Kinetic isotope effect Light water (disambiguation) Properties of water Goncharuk, ...
Craig, H. (1965). "The measurement of oxygen isotope paleotemperatures". In Tongiorgi, E. (ed.). Stable Isotopes in ... In a long-term project, Harmon Craig and Valerie Craig (his wife) used carbon and oxygen isotopes to identify the sources of ... During the 1950s Craig measured variations in the concentrations of hydrogen and oxygen isotopes in natural waters. In 1961, ... Craig also established the oxygen isotope shift in geothermal and volcanic fluids, demonstrating that the water is meteoric. ...
Isotope studies have become vital in examining natural histories. Oxygen, in particular, forms quite stable oxides; it requires ... Franchi, I; Greenwood, R; Howard, K; King, A; Lee, M; Anand, M; Findlay, R (2019). Oxygen Isotope Variation Of CM And Related ... However, CM and CO meteorites were found to have similar oxygen isotopes, indicating a relationship. CMs, like other C- ... CM and CI chondrites have a measurable difference in oxygen isotope levels. This suggests a different formation temperature, ...
Stable isotopes of hydrogen, oxygen, carbon, nitrogen, and sulphur can establish avian migratory connectivity between wintering ... Gabriel Bowen; Leonard Wassenaar; Keith Hobson (2005). "Global application of stable hydrogen and oxygen isotopes to wildlife ... Hobson, Keith; Wassenaar, Leonard (2008). Tracking Animal Migration with Stable Isotopes. Academic Press. ISBN 978-0-12-373867- ...
There is evidence from oxygen isotopes at Deep Sea Drilling Program sites that ice began to build up in Antarctica about 36 Ma ... A Middle Miocene δ18O increase, that is, a relative increase in the heavier isotope of oxygen, has been noted in the Pacific, ...
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: ... Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium ... 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 ...
A few other isotopes and radiotracers are slowly being introduced into oncology for specific purposes. For example, 11C- ... Because the oxygen atom that is replaced by F-18 to generate FDG is required for the next step in glucose metabolism in all ... Radionuclides used in PET scanning are typically isotopes with short half-lives[3] such as carbon-11 (~20 min), nitrogen-13 (~ ... Instead, the isotope must be prepared first, then afterward, the chemistry to prepare any organic radiotracer (such as FDG) ...
The formation of an Arctic ice cap around 3 million years ago is signaled by an abrupt shift in oxygen isotope ratios and ice- ...
The stable isotope signals in the layers of barnacle shells can potentially be used as a forensic tracking method for whales, ... Similarly, they have no gills, absorbing oxygen from the water through their limbs and the inner membrane of their carapaces. ... "Distinguishing between sea turtle foraging areas using stable isotopes from commensal barnacle shells". Scientific Reports. 9 ...
Iso-tope Abun-dance Hauf-life (t1/2) Decay mode Pro-duct ... Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon ...
Breathing allows oxygen (which humans and a lot of other species need for survival) to enter the lungs, from where it can be ... radioactive xenon isotopes). ... Gases and other drugs used in anaesthesia include oxygen, ...
Primordial isotopes of the alkali metals Z. Alkali metal. Stable. Decays. unstable: italics. odd-odd isotopes coloured pink ... Reaction with oxygen Upon reacting with oxygen, alkali metals form oxides, peroxides, superoxides and suboxides. However, the ... No primordial isotopes. (223. Fr. is a radiogenic nuclide) Radioactive: 40K, t1/2 1.25 × 109 years; 87Rb, t1/2 4.9 × 1010 years ... The other oxygen compounds are also unstable in water. 2KO2 + 2H2O → 2KOH + H2O2 + O2[145]. Li2O + H2O → 2LiOH. Reaction with ...
Researchers in the field do not agree on a theory for cold fusion.[126] One proposal considers that hydrogen and its isotopes ... joining oxygen produced at the anode.[27] For most of the time, the power input to the cell was equal to the calculated power ... This creates a high partial pressure, reducing the average separation of hydrogen isotopes. However, the reduction in ... the possible existence of fusion involving hydrogen isotopes in a planetary core.[24] In his original paper on this subject ...
... δ18O or delta-O-18 is a measure of the ratio of stable isotopes oxygen-18 (18O) and oxygen-16 (16O). It is commonly used as a ... Isotope geochemistry. References[edit]. *^ "USGS -- Isotope Tracers -- Resources -- Isotope Geochemistry". Retrieved 2009-01-18 ... "Forward Modeling of Carbonate Proxy Data from Planktonic Foraminifera Using Oxygen Isotope Tracers in a Global Ocean Model". ... As the observed isotope variations are similar in shape to the temperature variations recorded for the past 420 ky at Vostok ...
Boron acts as a "burnable" neutron absorber because its two isotopes, 10B and 11B, both transmute into stable nuclear reaction ... which limits the pathways for oxygen to diffuse into the material and react. Although addition of additives such as SiC can ... The synthesized powders exhibit 200 nm crystallite size and low oxygen content (~ 1.0 wt%). UHTC preparation from polymeric ...
Main isotopes of gadolinium. [[Isotope,IsoÀdàkọ:Shytope]] [[Natural abundance,AbunÀdàkọ:Shydance]] Half-life (t1/2) Decay mode ... Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium ...
The formation of an Arctic ice cap is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North ... "Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures and oxygen isotopes" (PDF) ...
Soddy first used the word "isotope" in: Soddy, Frederick (4 December 1913). "Intra-atomic charge". Nature. 92 (2301): 399-400. ... which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc and sulfur, which formed the basis for the modern list of ... They became known as isotopes, from the Greek eisos topos ("same place").[11][27] ...
Stable isotope analysis of strontium and oxygen can also be carried out. The amounts of these isotopes vary in different ... allowing researchers to partially reconstruct recent diet using stable isotopes as tracers. Nitrogen isotopes (14N and 15N) ... Stable isotope analysis monitors the ratio of carbon 13 to carbon 12 (13C/12C), which is expressed as parts per mil (per ... Based on stable isotope levels, eight Cobern Street Burial Ground individuals consumed a diet based on C4 (tropical) plants in ...
Other groups of archaea use sunlight as a source of energy (they are phototrophs). However, oxygen-generating photosynthesis ... Manhesa, Gérard; Allègre, Claude J.; Dupréa, Bernard & Hamelin, Bruno (1980). "Lead isotope study of basic-ultrabasic layered ... using either oxygen or metal ions as electron acceptors.[115] ...
Oxygen catastrophe: banded iron formations forms. Sleaford Orogeny on Australian continent, Gawler Craton 2,440-2,420 Ma. 2500[ ... Earliest evidence for life based on unusually high amounts of light isotopes of carbon, a common sign of life. 4280[36]. ... First known oxygen-producing bacteria. Oldest definitive microfossils. Oldest cratons on Earth (such as the Canadian Shield and ... Highest-ever atmospheric oxygen levels. Goniatites, brachiopods, bryozoa, bivalves, and corals plentiful in the seas and oceans ...
"for his discovery of the fixed relationship between the consumption of oxygen and the دگرگشت of اسید لاکتیک in the muscle"[۴۱] ... "for his work on the use of isotopes as tracers in the study of chemical processes"[۲۲] ...
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, ...
When labeled with the isotope fluorine-18 it is used as a radioligand in positron emission tomography (PET) studies of the ... Event-related functional magnetic resonance imaging can be used to detect changes in the Blood Oxygen Level Dependent (BOLD) ...
... atoms of an element which have different mass numbers are known as isotopes. For example, all atoms with 6 protons in their ... Carl Wilhelm Scheele isolated pure oxygen. ...
Carbon and oxygen nuclei collide with interstellar matter to form lithium, beryllium and boron in a process termed cosmic ray ... Cosmic rays are also responsible for the continuous production of a number of unstable isotopes in the Earth's atmosphere, such ... When cosmic rays enter the Earth's atmosphere they collide with atoms and molecules, mainly oxygen and nitrogen. The ... Cosmic rays ionize the nitrogen and oxygen molecules in the atmosphere, which leads to a number of chemical reactions. ...
Oxygen. Greek oxys. 8. &015.9994315.9994(3)[২][৩]. 16. 2 ... indicates the mass number of the longest-lived isotope of the ...
Clayton, Donald D. (2003). Handbook of Isotopes in the Cosmos: Hydrogen to Gallium. Cambridge University Press. ISBN 0521823811 ... Andrews, A. C. (1968). "Oxygen". Dalam Clifford A. Hampel. The Encyclopedia of the Chemical Elements. New York: Reinhold Book ... 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. ...
This innovation may have come from primitive eukaryotes capturing oxygen-powered bacteria as endosymbionts and transforming ... Analyses of carbon isotope ratios may help to explain major transitions such as the Permian-Triassic extinction event.[11] ... dissolved oxygen became more widespread and penetrated to greater depths; the development of life on land reduced the run-off ... and analyses of carbon isotope ratios may help to identify climate changes and even to explain major transitions such as the ...
Each reactor was designed to be able to produce at least 100% of the world's medical isotopes, meaning that the second reactor ... This caused a hydrogen-oxygen explosion inside the calandria. Several fuel bundles experienced melting and ruptured, rendering ... Medical isotope production using the 1957-built NRU reactor experienced two forced outages due to safety concerns (December ... In 1991, AECL decided to spin off its medical isotope production business under the name Nordion International Inc. The unit ...
Berkeley National Laboratory, The Isotopes Project. Hentet 21. april 2008.. *^ File:Binding energy curve - common isotopes.svg ... men udleder også oxygen.[111][112] Reaktionen sker således: 2 Li2O2 + 2 CO2 → 2 Li2CO3 + O2.. Nogle af de nævnte forbindelser, ... 2002). "Isotope-abundance variations of selected elements (IUPAC Technical Report)". Pure and Applied Chemistry 74 (10): 1987. ... En proces kendt som Atomic vapor laser isotope separation (forkortet "ALVIS") kan bruges til at separere lithiumisotoper, især ...
... with half-life of the most stable isotope, dubnium-268, being only 29 hours, and other isotopes even more radioactive. To date ... Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium ...
Solid tumors can outgrow their blood supply, causing a low-oxygen state known as hypoxia. Oxygen is a potent radiosensitizer, ... Isotopes commonly used in the treatment of bone metastasis are radium-223,[73] strontium-89 and samarium (153Sm) lexidronam.[74 ... One of the major limitations of photon radiation therapy is that the cells of solid tumors become deficient in oxygen. ... Targeting can be due to the chemical properties of the isotope such as radioiodine which is specifically absorbed by the ...
Oxygen isotope composition of HEDs and angrites. Data for angrites and HEDs from Greenwood et al. (2005). EFL: eucrite ... Miller M.F. (2002) Isotopic fractionation and the quantification of 17O anomalies in the three oxygen isotope system: an ... Meteoritical Bulletin: Oxygen Isotope Plots. Change plot type: CI, CM, CO, CV, and CK chondrites: d17O vs. d18O. CK compared to ...
Oxygen Isotope; Continental Crust; Pyroclastics; Igneous Activity; Oxygen Isotope Data. Other Numbering System:. Other ... The major features of the oxygen isotope data can be explained in terms of a simple two-component mixing model in which one end ... Turi, Bruno and Taylor, Hugh P., Jr. (1976) Oxygen isotope studies of potassic volcanic rocks of the Roman Province, Central ... Oxygen isotope studies of potassic volcanic rocks of the Roman Province, Central Italy ...
On the basis of the oxygen isotope composition of the aragonite precipitates, it was demonstrated that the equilibrium ... the equilibrium oxygen isotope fractionations between HCO 3 � as well as CO 3 2� and H2 Oa t 25C were also determined ... pH values and the speciation of carbonic acid species in these solutions were combined to yield the following oxygen isotope ... experimentally to estimate the oxygen isotope compositions of the HCO 3 � and CO 3 2� ions in the parent solutions. The ...
Calcium carbonate and stable oxygen isotope ratios of Globorotalia tumida from sediment core W8803B-T-42. PANGAEA, https://doi. ... Murray, Richard W; Leinen, Margaret W; Isern, Alexandra R (1993): (Table 2) Calcium carbonate and stable oxygen isotope ratios ...
... based on oxygen isotopes. Deep Sea Research Part I: Oceanographic Research Papers, 56(1), 89-106, https://doi.org/10.1016/j.dsr ... Stable oxygen isotope composition of planktic foraminifera at station GeoB3513-1 during fall. PANGAEA, https://doi.org/10.1594/ ... Wilke, Iris; Meggers, Helge; Bickert, Torsten (2009): (Appendix 3) Stable oxygen isotope composition of planktic foraminifera ... ecological preferences and calcification process on the incorporation of stable oxygen and carbon isotopes in planktic ...
... pizza gelsosomos pizza chesterton gelsyn-3 injection gelsyn injection isotopes definition isotopes examples isotopes of ... pizza gelsosomos pizza chesterton gelsyn-3 injection gelsyn injection isotopes definition isotopes examples isotopes of ... The oxygen-abundant nature of GO means the fabric is hydrophilic and readily dispersible in water. GO has additionally been ... isotopes define. *"The Main Concern is HIV, Everything Else is Fixable": Indifference Toward Sexually Transmitted Infections in ...
Geomorphology and climate of the cool oxygen isotope stage 3 in compari¬son with the cold stages 2 and 4 in The Nether¬lands. ... Geomorphology and climate of the cool oxygen isotope stage 3 in compari¬son with the cold stages 2 and 4 in The Nether¬lands. ... Geomorphology and climate of the cool oxygen isotope stage 3 in compari¬son with the cold stages 2 and 4 in The Nether¬lands. ... Geomorphology and climate of the cool oxygen isotope stage 3 in compari¬son with the cold stages 2 and 4 in The Nether¬lands. ...
Modern speleothem oxygen isotope hydroclimate records in water-limited SE Australia. Geochimica et Cosmochimica Acta 270 , pp. ...
Oxygen, for example, has three isotopes: 16O,^ 17^O and ^ 18^O, indicating differences in the number of neutrons each nucleus ... Compare any two samples of oxygen found on Earth and youll find the proportions of 16O,^ 17^O and^ 18^O isotopes are almost ... So if you find that a sample has the same oxygen isotope composition as one from Earth, then its very likely the sample came ... Previous research has established that the oxygen isotope composition of lunar samples is indistinguishable from that of Earth ...
Oxygen isotopes (D. Rumble, CIW): acid-washed material analyzed in replicate by laser fluorination gave, respectively, δ18O = ... O isotopes:. Institutions. and collections. NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, ... Classification: Achondrite (eucrite). Although this specimen has mineral compositions and oxygen isotopic composition similar ...
Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O 2.907, ... O isotopes:. Institutions. and collections. UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM ...
Oxygen isotopes (K. Ziegler, UNM): acid-washed material analyzed in 11 replicates by laser fluorination gave, respectively δ18O ... ungrouped classification is based on oxygen isotope values similar to the PMG, but unlike any known pyroxene pallasite. ... O isotopes:. Institutions. and collections. UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM ...
Spatial distribution of mean winter air temperatures in Siberian permafrost at 20-18 ka BP using oxygen isotope dataстатья ... The same difference between the oxygen isotope composition of ice wedges in the eastern and western regions of Siberian ...
... we have undertaken a geochemical and oxygen isotope study of main-group pallasites and dunitic rocks from mesosiderites. Oxygen ... Oxygen isotope analysis of olivine by ion microprobe: Matrix effects and applications to a serpentinised dunite ... Geochemistry and oxygen isotope composition of main-group pallasites and olivine-rich clasts in mesosiderites: Implications for ... Geochemistry and oxygen isotope composition of main-group pallasites and olivine-rich clasts in mesosiderites: Implications for ...
Paquette, J.; Engrand, C.; Stenzel, O.; Hilchenbach, M.: Measuring Oxygen Isotopes with COSIMA. American Geophysical Union Fall ...
Oxygen Isotopes in Tree Rings from Greenland: A New Proxy of NAO ... Hafnium isotope constraints on the nature of the mantle beneath ... but uniform for tree-ring stable isotopes along an aridity gradient in for tree-ring stable isotopes along an aridity gradient ... Stable isotope paleoecology of the late Miocene Baynunah Formation, Abu Dhabi, United Arab Emirates ... Molecular and isotopic evidence reveals the end-Triassic carbon-isotope excursion is not from massive exogenous light carbon ...
The only "proxy" we use are oxygen isotope ratios. Oxygen isotope ratios (δ18O) in polar snow are well known to be correlated ... wouldnt eutrophication speed up the time line in terms of no longer being a carbon sink as the oceans are depleted of oxygen ...
Tropical Atlantic coral oxygen isotopes: glacial-interglacial sea surface temperatures and climate change ...
Oxygen isotopes of a 1.5 mg olivine sample (C. Suavet, C. Sonzogni, CEREGE): δ17O = 1.04 ‰, δ18O = 3.98 ‰, and Δ17O = -1.03 ‰. ... O isotopes:. Institutions. and collections. CEREGE: CEREGE BP 80 Avenue Philibert, Technopole de lArbois 13545 Aix-en-Provence ...
They show that the ratios of oxygen isotopes are almost identical on the Earth and the moon, suggesting the two bodies formed ... Meteorites from Mars and asteroids have very different oxygen isotope compositions from the Earth, so the impacting proto- ... "How do you end up with a moon and Earth that have identical oxygen isotope composition?" ...
"Ice-free conditions in Sweden during Marine Oxygen Isotope Stage 3?". Boreas 39: 377-98. doi:10.1111/j.1502-3885.2009.00137.x. ...
U-series and oxygen isotope chronology of the mid-Pleistocene Lake Amora (Dead Sea basin) ... Carbon isotope variability across the Ediacaran Yangtze platform in South China: Implications for a large surface-to-deep ocean ... Comment on A critical evaluation of the boron isotope-pH proxy: The accuracy of ancient ocean pH estimates by M. Pagani, D. ... Stable isotope record of the terminal Neoproterozoic Krol platform in the Lesser Himalayas of northern India ...
The Oxygen isotopes (as I described) are the temperature proxies. Carbon isotopes are telling us different but related things, ... 12O and 13O oxygen isotope ratio as a marine shell temperature proxy. Its a typo. Sorry. Theyre carbon isotopes; C does ... For example, the ratio of 2 isotopes of oxygen, 12O and 13O, is a common proxy for temperature from marine shells, and has been ... "For example, the ratio of 2 isotopes of oxygen, 12O and 13O, is a common proxy for temperature from marine shells, and has been ...
Magnetite contains 2.7±0.1 wt.% Cr2O3, 0.67 wt.% Al2O3, 0.55 wt.% NiO (N=3); Oxygen isotopes: (I. Franchi, R. Greenwood, OU) δ ... O isotopes:. Institutions. and collections. OU: Planetary and Space Sciences Department of Physical Sciences The Open ...
Oxygen isotopes: (D. Rumble, CIW) Analyses of two whole rock fragments by laser fluorination gave, respectively, δ18O = 3.95, ... O isotopes:. Institutions. and collections. UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson ...
She blames it on oxygen-15, a radioactive isotope of the common oxygen-16. I wonder if she knows that the half-life of O-15 is ... Perhaps someone should make her aware of the difference between radio-active and reactive oxygen; the two words do sound ...
A 16-Ma record of paleodiet using carbon and oxygen isotopes in fossil teeth from Pakistan. Chemical Geology (Isotope ... In the case of homeothermic animals in general, the oxygen isotope composition of apatite depends primarily on the oxygen ... Oxygen isotope measurements of phosphate from fish teeth and bones. Earth and Planetary Science Letters 20: 337-340.. Lund, P.W ... A model of oxygen isotope fractionation in body water of large mammals. Geochimica et Cosmochimica Acta 59: 4523-4537.. Bryant ...
Oxygen isotopes: (I. Kohl and E. Young, UCLA) δ17O 1.868, δ18O 3.914, Δ17O -0.209 (all normalized). EPMA, in wt.%, derived from ... O isotopes:. Institutions. and collections. UCLA: Institute of Geophysics and Planetary Physics, University of California, Los ...
Stable oxygen isotope values show an increase in water temperature of... ... stable isotopes and Ca/Cd), and unpublished results of total carbon, organic carbon, and calcium carbonate analyses of ... New benthic and planktic foraminiferal assemblage census data and Benthic Foraminiferal Oxygen Index (BFOI) values, previously ... Stable oxygen isotope values show an increase in water temperature of ~1??C from the late glacial to late Holocene and a change ...
Mikalsen, G.; Hald, Morten; Husum, K.. Benthonic stable oxygen isotope records from Northern Norwegian fjords, showing ... Mikalsen, G.; Hald, Morten; Husum, K.. Benthonic stable oxygen isotope records from Northern Norwegian fjords, showing ... Dokken, T.; Hald, Morten. Rapid climatic shifts during isotope stages 2-4 in the Polar North Atlantic. Geology 1996; Volum 7. ... bivalve and stable-isotope stratigraphy in Van Mijenfjord, Spitzbergen. 15th session of Scientific School on Marine Geology, ...

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