Nitrous oxide oceans

A variety of nitrogen oxides (NO ) such as nitric oxide (NO) and nitrogen dioxide (NO2) as well as nitrous oxide (N2O) are present in the atmosphere. The sources of these oxides are biological actions and organic decomposition in the soil and in the ocean... 

Fig. 1.2), most of which escapes to the atmosphere (see Fig. 1.1 as well as Chapter 2 by Bange, this volume). Nitrous oxide acts as a greenhouse gas that is more than 200 times more potent than CO2 (Ramaswamy et ah, 2001). Therefore variations of this gas in the atmosphere can lead to changes in Earth s temperature and cHmate. Since the oceanic emission of N2O constitutes a substantial fraction to the total emission of N2O into the atmosphere, N2O provides for a direct potential link between the ocean nitrogen cycle and Earth s climate. 

Codispoti, L. A., and Christensen, J. P. (1985). Nitrification, denitrification and nitrous oxide cycling in the Eastern Tropical South Pacific Ocean. Mar. Chem. 16, 277—300. 

Suntharalingam, P., and Sarmiento, J. L. (2000). Factors governing the oceanic nitrous oxide distribution Simulations with an ocean general circulation model. Global Biogeochem. Cycles 14(1), 429 54. 

Nitric oxide (NO), nitrous oxide (N2O), dinitrogen (N2), and ammonia (NH3) are constituents of the Earth s atmosphere. They play important roles in the chemistry and climate of the present-day Earth. Moreover, they are intermediates of the oceanic nitrogen cycle. In contrast to most of the other components of the oceanic nitrogen cycle, they exist as dissolved gaseous molecules. Being gases they can be transferred across the seasurface-troposphere interface. 

Bange, H. W. (2006b). New Directions The importance of the oceanic nitrous oxide emissions. Atmos. Enpiron. 40(1), 198—199. 

Goldstein, B.,Joos, F., and Stocker, T. F. (2003). A modeling study of oceanic nitrous oxide during the Younger Dryas cold period. Geophys. Res. Lett. 30(2), doi 10.1029/2002GL016418. 

Oudot, C., Andrie, C., and Montel, Y. (1990). Nitrous oxide production in the tropical Atlantic Ocean. Deep-Sea Res. 37, 183—202. 

Walter, S., Peeken, I., Lochte, K., Webb, A., and Bange, H. W. (2005). Nitrous oxide measurements during EIFEX, the European Iron Fertilization Experiment, in the subpolar South Atlantic Ocean. Geophys. Res. Lett. 32, L 23613, doi 10.1029/2005GL024619. 

Walter, S., Bange, H. W., Breitenbach, U., and Wallace, D. W. R. (2006a). Nitrous oxide in the North Atlantic Ocean. Biogeosci. Discuss. 3, 993—1022. 

Codispoti, L., Brandes, J., Christensen, J., Devol, A., Naqvi, S., Paerl, H., and Yoshinari, T. (2001). The oceanic fixed nitrogen and nitrous oxide budgets Moving targets as we enter the anthro-pocene Scientia Marina. 65(Supp. 2), 85—105. 

Law, C. S., and Owens, N. J. P. (1990). Significant flux of atmospheric nitrous oxide from the northwest Indian Ocean. Nature 346, 826-828. 

Weiss, R. F. (1978). Nitrous oxide in surface water and marine atmosphere of the North Atlantic and Indian Oceans. EOS Trans. Amer. Geophys. Union 59, 1101. 

Figure 16.10 (A) Nitrous oxide (N2O) concentrations and isotopic composition for water samples collected at Station ALOHA. [Left] Depth profile of N2O showing a distinct mid-depth maximum of 60 nM coincident with the dissolved oxygen minimum. [Center] N isotope composition of N2O. [Right] 0 isotope composition of N2O. Data from Dore et al. (1998) and B. Popp and J. Dore (unpublished). (B) N2O saturation state, expressed as a percentage of air saturation, for the upper portion of the water column at Station ALOHA during the period September 1992— September 1994. The vertical dashed line indicates equilibrium (100% saturation) with atmospheric N2O. With the exception of one measured value on cruise HOT-45, all determinations indicate significant N2O saturation relative to the atmosphere which implies both a local source and a net ocean-to-air gas flux.From Dore and Karl (1996a).

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