Anaerobic ammonium oxidation by nitrite (anammox): Implications for N₂ production in coastal marine sediments

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• 作者：Engströ ; m ; Pia ; Dalsgaard ; Tage ; Hulth ; Stefan ; Aller ; Robert C.
• 刊名：Geochimica et Cosmochimica Acta
• 出版年：2005
• 期刊代码：27_00167037
• 类别：ear
• 出版时间：April 15, 2005
• 卷：69
• 期：8
• 页码：2057-2065
• 文件大小：378 K

摘要

The respiratory reduction of nitrate (denitrification) is acknowledged as the most important process that converts biologically available nitrogen to gaseous dinitrogen (N₂) in marine ecosystems. Recent findings, however, indicate that anaerobic ammonium oxidation by nitrite (anammox) may be an important pathway for N₂ formation and N removal in coastal marine sediments and in anoxic water columns of the oceans. In the present study, we explored this novel mechanism during N mineralization by p>15p>N amendments (single and coupled additions of p>15p>NH₄p>+p>, p>14p>NO₃p>−p> and p>15p>NO₃p>−p>) to surface sediments with a wide range of characteristics and overall reactivity. Patterns of p>29/30p>N₂ production in the pore water during closed sediment incubations demonstrated anammox at all 7 of the investigated sites. Stoichiometric calculations revealed that 4%to 79%of total N₂ production was due to this novel route. The relative importance of anammox for N₂ release was inversely correlated with remineralized solute production, benthic O₂ consumption, and surface sediment Chl a. The observed correlations indicate competition between reductants for pore water nitrite during early diagenesis and that additional factors (e.g. availability of Mn-oxides), superimposed on overall patterns of diagenetic activity, are important for determining absolute and relative rates of anammox in coastal marine sediments.