We report observations of stratospheric CO2 that reveal surprisingly large anomalous enrichments in (17)O that vary systematically with latitude, altitude, and season. The triple isotope slopes reached 1.95 ± 0.05(1σ) in the middle stratosphere and 2.22 ± 0.07 in the Arctic vortex versus 1.71 ± 0.03 from previous observations and a remarkable factor of 4 larger than the mass-dependent value of ...

The oxygen isotope composition of terrestrial sulfate is affected measurably by many Earth-surface processes. During the Neoproterozoic, severe "snowball" glaciations would have had an extreme impact on the biosphere and the atmosphere. Here, we report that sulfate extracted from carbonate lenses within a Neoproterozoic glacial diamictite suite from Svalbard, with an age of approximately 635 mi...

The most notable trend in the sedimentary iron isotope record is a shift at the end of the Archean from highly variable δ56 Fe values with large negative excursions to less variable δ56 Fe values with more limited negative values. The mechanistic explanation behind this trend has been extensively debated, with two main competing hypotheses: (i) a shift in marine redox conditions and the transit...

Stable oxygen isotope ratios of foraminiferal calcite are widely used in paleoceanography to provide a chronology of temperature changes during ocean history. It was recently demonstrated that the stable oxygen isotope ratios in planktonic foraminifera are affected by changes of the seawater chemistry carbonate system: the dO of the foraminiferal calcite decreases with increasing CO3 22 concent...

Growth and mortality of microorganisms have been characterized through DNA stable isotope probing (SIP) with 18O-water in soils from a range of ecosystems. Conventional SIP has been improved by sequencing a marker gene in all fractions retrieved from an ultracentrifuge tube to produce taxon density curves, which allow estimating the atom percent isotope composition of each microbial taxon's gen...

served in the Earth's mantle are commonly explained by the addition of a late veneer of primitive meteoritic material to the mantle after core formation was complete [1-3]. The composition of the late veneer has been inferred from the comparision of Os isotope compositions and relative HSE abundances in Earth's primitive mantle to those of chondritic meteorites [4-11]. However, while the 187 Os...

Isotope clusters in library electron ionization mass spectra of germanes often appear a few u lower than theoretically expected from elemental composition; for example, the dominant peak of the Ge(4)H(10)(+) pattern is shifted 8 u down. This phenomenon is due to combinations of three essential components: the molecular ion Ge(n)H(2n+2)(+) and two products of hydrogen elimination, Ge(n)H(+) and ...

[1] The stable H and O isotope composition of river and stream water records information on runoff sources and land‐atmosphere water fluxes within the catchment and is a potentially powerful tool for network‐based monitoring of ecohydrological systems. Process‐based hydrological models, however, have thus far shown limited power to replicate observed large‐scale variation in U.S. surface water ...

It has been reported in previous research that the lead isotopic composition of blood, urine and feces samples statistically differed from the given lead sources in Sprague-Dawley (SD) rats. However, the reason for this phenomenon is still unclear. An animal experiment was performed to investigate the lead isotope fractionation in diverse biological samples (i.e., lungs, liver, kidneys, bone) a...

The appearance of agriculture in the Fertile Crescent propelled the development of Western civilization. Here we investigate the evolution of agronomic conditions in this region by reconstructing cereal kernel weight and using stable carbon and nitrogen isotope signatures of kernels and charcoal from a set of 11 Upper Mesopotamia archaeological sites, with chronologies spanning from the onset o...