• variability
  • In the summer of 2006, researchers measured the oxygen isotope ratio of rainwater collected in the nation's capital, Niamey, to determine the connection between intraseasonal atmospheric variability and precipitation. (phys.org)
  • The stable isotopes of water in the climate system are unique tracers of moisture transport and tropical rainfall variability. (usc.edu)
  • Isotope chronologies of Pinus merkusii from a coastal lowland forest in Cambodia have been generated to investigate hydrological variability over the Indo-Pacific Warm Pool (IPWP), based on the aforementioned observation that the δ¹⁸O in precipitation reflects the hydroclimate of the moisture source region. (usc.edu)
  • In the 1990s, in addition to continued work on radiocarbon calibration and solar variability, he began work on oxygen isotopes from Greenland ice cores together with Pieter Grootes. (wikipedia.org)
  • temperatures
  • A higher abundance of 18O in calcite is indicative of colder water temperatures, since the lighter isotopes are all stored in the glacial ice. (wikipedia.org)
  • Isotopic disequilibrium in the Kanaga system is manifest in two ways: two types of basaltic inclusions with contrasting δ 18 O values (6.0‰ and 6.5‰) occur in one andesite (δ 18 Oplag = 6.6‰), and in two other andesites plagioclase-titanomagnetite and clinopyroxene-titanomagnetite oxygen isotope temperatures are inconsistent. (geoscienceworld.org)
  • One andesite, however, yields concordant oxygen isotope temperatures of ∼850 ±100 °C, and a two-pyroxene temperature of 920 ±50 °C. Assimilation of isotopically heavy crustal wall rock and mixing off basaltic and andesitic magmas explains the variable and high δ 18 Oplag values and low eruptive temperature of the Kanaga andesites. (geoscienceworld.org)
  • Bold for stable isotopes The ratio between 16O and 18O is used to deduce ancient temperatures Can be used in NMR studies of metabolic pathways Can be used in studying certain metabolic pathways Oxygen isotopes with 25-28 nucleons exist for less than 1 microsecond, since they are beyond the neutron drip line. (wikipedia.org)
  • otoliths
  • RATIONALE: The oxygen isotope ratio (δ(18) O value) of aragonite fish otoliths is dependent on the temperature and the δ(18) O value of the ambient water and can thus reflect the environmental history of a fish. (biomedsearch.com)
  • Secondary ion mass spectrometry (SIMS) offers a spatial-resolution advantage over conventional acid-digestion techniques for stable isotope analysis of otoliths, especially given their compact nature. (biomedsearch.com)
  • carbon
  • The carbon dioxide provides two of the oxygen atoms in the calcite. (wikipedia.org)
  • Responsible for these fluctuations in oxygenation were likely driven by the Lomagundi carbon isotope excursion. (wikipedia.org)
  • Minze Stuiver's research encompassed the use of radiocarbon (14C) to understand solar cycles and radiocarbon production, ocean circulation, lake carbon dynamics and archaeology as well as the use of stable isotopes to document past climate changes. (wikipedia.org)
  • The ratio of carbon-13 and carbon-12 isotopes in these types of plants is as follows: C4 plants: -16 to -10 ‰ CAM plants: -20 to -10 ‰ C3 plants: -33 to -24 ‰ Limestones formed by precipitation in seas from the atmospheric carbon dioxide contain normal proportion of 13C. (wikipedia.org)
  • continental crust
  • 18O values imply that LVC magmas contain on a molar oxygen basis approximately 42 to 4% isotopically heavy continental crust, with proportions declining in a broadly regular fashion toward the center of the LVC. (usgs.gov)
  • 18O values of the rhyodacitic rocks suggest that the continental crust in the melt generation zones beneath the LVC has been substantially modified by intrusion of mantle-derived basaltic magmas, with the degree of hybridization ranging on a molar oxygen basis from approximately 60% at distances up to 12 km from the center of the system to 97% directly beneath the focus region. (usgs.gov)
  • precipitation
  • The cellulose δ¹⁸O annual mean values correlate significantly with the amount of summer monsoon precipitation over the India subcontinent, corroborating recent studies that suggest the so-called "isotope amount effect" in the tropical precipitation δ¹⁸O reflects the hydrological processes of the upstream or the moisture source regions instead of the rainfall amount at the local site. (usc.edu)
  • The analysis of model outputs from a water isotope-enabled atmospheric model is used in conjunction with isotopic data from tree cellulose and precipitation to investigate moisture sources and how these sources of moisture vary on different timescales. (usc.edu)
  • metabolic
  • An extension of this research resulted in development of DNA-based stable-isotope probing, which allows examination of links between metabolic function and taxonomic identity of microorganisms in the environment, without the need for culture isolation. (wikipedia.org)
  • naturally
  • Naturally occurring oxygen is composed of three stable isotopes, 16O, 17O, and 18O, with 16O being the most abundant (99.762% natural abundance). (wikipedia.org)
  • Since physicists referred to 16O only, while chemists meant the naturally-abundant mixture of isotopes, this led to slightly different mass scales between the two disciplines. (wikipedia.org)
  • trace
  • Combined with Sr isotope and trace element data, δ 18 Oplag values suggest a variable magma source characterized by differences in the mantle wedge or the subducted sediment component along the volcanic front. (geoscienceworld.org)
  • neutrons
  • Oxygen-15 and nitrogen-13 are produced in the atmosphere when gamma rays (for example from lightning) knock neutrons out of oxygen-16 and nitrogen-14: 16O + γ → 15O + n 14N + γ → 13N + n The oxygen-15 decays with a half-life of about two minutes to nitrogen-15, emitting a positron. (wikipedia.org)
  • secondary
  • Using the NanoSIMS (nanometer-scale secondary-ion mass spectrometer) at Lawrence Livermore National Laboratory in Livermore, Calif., Simon and scientists from LLNL, University of California, Berkeley, and the University of Chicago measured the concentrations of oxygen isotopes found in a calcium-aluminum-rich inclusion (CAI) contained in a piece of the Allende meteorite. (nasa.gov)
  • Otolith oxygen isotopes measured by high-precision secondary ion mass spectrometry reflect life history of a yellowfin sole (Limanda aspera). (biomedsearch.com)
  • Both 17O and 18O are secondary isotopes, meaning that their nucleosynthesis requires seed nuclei. (wikipedia.org)
  • evidence
  • The paper presents evidence that CAIs formed from several oxygen reservoirs, likely in distinct regions of the solar nebula. (nasa.gov)
  • temperature
  • precision need to be as high as ~10−5, for that isotope signals of interest are often less than 10−3) The temperature dependent relationship is subtle (-0.0005% per oC) (Quade 2007). (wikipedia.org)
  • Water
  • Thus, the oxygen isotope ratio found in a water sample can indicate the water's history. (phys.org)
  • The isotope ratio in the calcite is therefore the same, after compensation, as the ratio in the water from which the microorganisms of a given layer extracted the material of the shell. (wikipedia.org)
  • High-resolution water isotope records are developed from trees collected from northern Thailand, southern Cambodia, and eastern part of the Tibetan Plateau. (usc.edu)
  • Different
  • For example, different sources and sinks of methane have different affinity for the 12C and 13C isotopes, which allows distinguishing between different sources by the 13C/12C ratio in methane in the air. (wikipedia.org)
  • useful
  • Zircon is also useful because its incorporation of other elements like uranium, lutetium, samarium, and oxygen can be analyzed to provide further insight into the age and conditions the crystal grew under. (wikipedia.org)
  • Zircons are known to be relatively retentive of their incorporated isotopes and thus very useful for microquantitative studies. (wikipedia.org)
  • data
  • 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 . (nsidc.org)
  • 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. (nsidc.org)
  • chemical
  • Nearly all chemical processes fractionate 17O and 18O in a mass-dependent way relative to 16O, a major exception being the formation of ozone from diatomic oxygen in the presence of UV radiation or electrical discharge. (open.ac.uk)