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There are three naturally occurring isotopes of carbon: 12, 13, and 14. 12 C and 13 C are stable, occurring in a natural proportion of approximately 93:1. 14 C is produced by thermal neutrons from cosmic radiation in the upper atmosphere, and is transported down to earth to be absorbed by living biological material. Isotopically, 14 C
1 paź 2019 · Here we review the application of stable carbon isotope ratios in ocean water and biogenic carbonates as proxies in paleoceanography, including the atmospheric and sedimentary reservoirs oceanic carbon is in exchange with.
17 sty 2018 · At present the global mean stable carbon isotope composition of C 3 plants (δ13 C p), most of Earth’s vegetation, is about −27‰ relative to VPDB, although δ13 C varies widely between about...
15 mar 2021 · Using a numerical model and globally distributed ocean observations of stable carbon isotopes, we estimate terrestrial carbon inputs to the ocean at 1.4 ± 0.5 GtC/yr, with 95% of the coastal margin inputs (0.8 ± 0.5 GtC/yr) occurring in the Pacific and Indian Oceans.
28 wrz 2021 · Stable isotopes of hydrogen, carbon and oxygen are used to investigate numerous physical and chemical processes in the water and inorganic carbon cycles. Measuring and comparing natural...
1 lis 2021 · Here, we review the stable carbon isotope records of C 3 land plants (δ 13 C plant) in various forms in Paleozoic sediments (mostly Devonian, Carboniferous, and Permian), as well as marine carbonate carbon isotopes (δ 13 C carb), and interpret them in the context of global carbon cycle.
23 paź 2020 · Carbon isotopes are present in the atmosphere, ocean, and terrestrial biosphere in ratios of approximately 99% 12 C/C, 1% 13 C/C, and 1 × 10 −12 14 C/C. 12 C and 13 C are stable isotopes while 14 C is a radioactive isotope called radiocarbon.
