Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, USA.
Science. 2014 Apr 25;344(6182):406-8. doi: 10.1126/science.1248364. Epub 2014 Apr 10.
Biologically available nitrogen limits photosynthesis in much of the world ocean. Organic matter (OM) stoichiometry had been thought to control the balance between the two major nitrogen removal pathways-denitrification and anammox-but the expected proportion of 30% anammox derived from mean oceanic OM is rarely observed in the environment. With incubations designed to directly test the effects of stoichiometry, however, we showed that the ratio of anammox to denitrification depends on the stoichiometry of OM supply, as predicted. Furthermore, observed rates of nitrogen loss increase with the magnitude of OM supply. The variable ratios between denitrification and anammox previously observed in the ocean are thus attributable to localized variations in OM quality and quantity and do not necessitate a revision to the global nitrogen cycle.
在世界海洋的大部分地区，生物可利用氮限制了光合作用。有机物质（OM）化学计量学曾被认为控制着两种主要氮去除途径——反硝化作用和厌氧氨氧化作用——之间的平衡，但在环境中很少观察到海洋 OM 的预期 30%来自厌氧氨氧化作用的比例。然而，通过设计旨在直接测试化学计量学影响的培养实验，我们表明，正如预测的那样，厌氧氨氧化作用与反硝化作用的比例取决于 OM 供应的化学计量学。此外，观察到的氮损失速率随着 OM 供应的增加而增加。因此，海洋中以前观察到的反硝化作用和厌氧氨氧化作用之间的可变比例归因于 OM 质量和数量的局部变化，而不需要对全球氮循环进行修订。
