• composition
  • The oxygen isotropic composition (delta 18O) of coral skeletons reflects a combination of sea surface temperature (SST) and the delta 18O of seawater, which is related to sea surface salinity (SSS). (upenn.edu)
  • Oxygen isotopic measurements in the core and outer rim of a calcium-aluminum-rich inclusion contained in the Allende meteorite record the entire range of oxygen isotopic composition previously measured in all solids in the solar system. (nasa.gov)
  • Through oxygen isotopic analysis, the team found that the CAI moved farther from the sun, where the CAI exchanged oxygen with at least one separate gaseous reservoir that was similar in composition to that of the building materials of the terrestrial planets. (nasa.gov)
  • The authors also detect a number of shorter-period shifts in water vapor isotopic composition , which they suggest are driven by convective processes, like evaporation and subsidence, and daily atmospheric mixing, potentially opening the door for oxygen isotope measurements to be used to study atmospheric variability and dynamics and thus the origin of Niger's moisture. (phys.org)
  • Buchwald, C. , A. E. Santoro , M. R. McIlvin , and K. L. Casciotti ( 2012 ), Oxygen isotopic composition of nitrate and nitrite produced by nitrifying cocultures and natural marine assemblages , Limnol. (wiley.com)
  • Casciotti, K. L. , D. M. , M. G. Hastings , J. K. Bohlke , and A. Hilkert ( 2002 ), Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method , Anal. (wiley.com)
  • Past variability in upper ocean thermocline depth is commonly estimated from the abundance of different species of planktonic organisms or the difference in oxygen isotopic composition between two species of planktonic foraminifera, one that lives in the mixed layer and one that lives in or near the thermocline. (columbia.edu)
  • To test the latter relationships, we measured the oxygen isotopic composition of eight species of planktonic foraminifera (pink and white varieties of Globigerinoides ruber, Globigerinoides sacculifer without the final chamber, Orbulina universa, Pulleniatina obliquiloculata, Globorotalia menardii, Neogloborotalia dutertrei, and Globorotalia tumida) in surface sediment samples from 31 tropical Atlantic deep-sea sediment cores. (columbia.edu)
  • The isotopic composition of oxygen atoms in the Earth's atmosphere is 99.759% 16O, 0.037% 17O and 0.204% 18O. (wikipedia.org)
  • calcite
  • Elemental and stable isotope data measured in Eocene foraminiferal calcite from Ocean Drilling Program Site 865 and Tanzanian Drilling Project Site 18 published in Edgar et al. (bgs.ac.uk)
  • 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)
  • cores
  • 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)
  • 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
  • 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)
  • 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)
  • data
  • 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)
  • Processes
  • 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)
  • 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)