气候变化领域集成服务门户(CCPortal): Model experiment on heterotrophic denitrification vs. autotrophic anammox - quantifying collateral effects on the oceanic carbon cycle

CCPortal

DOI	https://doi.org/10.1594/PANGAEA.843015
	Model experiment on heterotrophic denitrification vs. autotrophic anammox - quantifying collateral effects on the oceanic carbon cycle
	Koeve; Wolfgang; Kähler; Paul
发布日期	2015-02-20
数据集类型	dataset
英文简介	The conversion of fixed nitrogen to N2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO2. At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N2-production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ) focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N2-production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy (deltaCO2:deltaN2), varying between 1.7 and 6.5, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic N-conversions are supported by diffusive fluxes of NH4+ originating from neighbouring waters with sulphate reduction, much lower values of Delta CO2:Delta N2 can be found. However, accounting for concomitant diffusive fluxes of CO2, the ratio approaches higher values similar to those computed for open ocean OMZs. Based on this analysis, we question the significance of collateral effects concerning the trophic nature of suboxic N-conversions on the marine carbon cycle.
语种	英语
国家	国际
学科大类	气候变化
学科子类	气候变化
文献类型	数据集
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/217176
推荐引用方式 GB/T 7714	Koeve,Wolfgang,Kähler,et al. Model experiment on heterotrophic denitrification vs. autotrophic anammox - quantifying collateral effects on the oceanic carbon cycle.2015-02-20.https://doi.org/10.1594/PANGAEA.843015.