نتایج جستجو برای: carbon and sulfur stable isotopes
تعداد نتایج: 16921217 فیلتر نتایج به سال:
Stable isotope analysis of human remains has been used to address long-standing debates regarding the speed and degree to which the introduction of farming transformed diet. In Europe, this debate has centered on northern and Atlantic regions with much less attention devoted to the arrival of farming across the Mediterranean. This study presents carbon and nitrogen stable isotope analyses of co...
Over a century ago, Frederick Soddy provided the first evidence for the existence of isotopes; elements that occupy the same position in the periodic table are essentially chemically identical but differ in mass due to a different number of neutrons within the atomic nucleus. Allied to the discovery of isotopes was the development of some of the first forms of mass spectrometers, driven forward...
The marine subsurface is a reservoir of the greenhouse gas methane. While microorganisms living in water column and seafloor ecosystems are known to be a major sink limiting net methane transport from the marine subsurface to the atmosphere, few studies have assessed the flow of methane-derived carbon through the benthic mat communities that line the seafloor on the continental shelf where meth...
BACKGROUND The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea hydrothermal vent sites at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. METHODOLOGY/PRINCIPAL FINDINGS We analyzed specimens from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge by...
Phanerozoic levels of atmospheric oxygen relate to the burial histories of organic carbon and pyrite sulfur. The sulfur cycle remains poorly constrained, however, leading to concomitant uncertainties in O2 budgets. Here we present experiments linking the magnitude of fractionations of the multiple sulfur isotopes to the rate of microbial sulfate reduction. The data demonstrate that such fractio...
Laser desorption mass spectrometry was used in the production and analysis of gas phase metal sulfur clusters. Clusters of gas phase aluminum, gallium, and indium sulfur were produced and analyzed using a time-of-flight mass spectrometer. Also, carbon nano-onions produced by an arc between graphite electrodes in water and the annealing of nanodiamonds were analyzed. The sulfur experiments were ...
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