Nitrogen isotopes in the oceans

Carbon Dioxide (CO2) Cycle. Nitrogen Isotopes in the Ocean. Tritium-Helium Dating. 

Anthropogenic Trace Elements in the Ocean. Atmospheric Input of Pollutants. Carbon Cycle. Conservative Elements. Hydrothermal Vent Fluids, Chemistry of. Marine Silica Cycle. Metal Pollution. Nitrogen Cycle. Platinum Group Elements and their Isotopes in the Ocean. Refractory Metals. River Inputs. Transition Metals and Heavy Metal Speciation. 

Sigman et al. [134] have pointed out that nitrate is the predominant form of bioavailable (or fixed ) nitrogen in the ocean, and the natural isotopic... 

Sweeney, R. E., Liu, K. K., Kaplan, I. R., Oceanic Nitrogen Isotopes and Their Uses in Determining the Source of Sedimentary Nitrogen, In Stable Isotopes in the Earth Sciences, pp. 9-26, Wellington, New Zealand, 1978. 

McCarthy, M. D., Benner, R., Lee, C., Hedges, J. I., and Fogel, M. L. (2004). Amino acid carbon isotopic fractionation patterns in oceanic dissolved organic matter An unaltered photoautotrophic source for dissolved organic nitrogen in the ocean Marine Chemistry 92(1-4), 123-134. 

Meador, T. B., Aluwihare, L. I., and Mahaffey, C. (2007). Isotopic heterogeneity and cycling of components of the dissolved organic nitrogen pool in the oligotrophic ocean. Limnology and Oceanography 52(3), 934—947. 

The amount of sedimentary denitrification occurring in the ocean today is one of the most poorly quantified terms in the marine combined nitrogen budget. Most modem measurements of denitrification rate have utilized pore-water N03 profiles (estimated from diffusion calculations—reaction models) whole-sediment incubations, either on deck or in situ, or by the isotope paring technique. It appears that shelf and upper slope sediments are quantitatively the most important sites of sedimentary denitrification (Christensen, et al., 1996 Christensen et al., 1987 Devol, 1991 Devol and Christensen, 1993 Gruber and Sarmiento, 1997 Kristensen, et al., 1999 Middelburg et al., 1996). Typical denitrification rates in these areas... 

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