The environmental controls that govern the end product of bacterial nitrate respiration
The environmental controls that govern the end product of bacterial nitrate respiration
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DOI：
10.1126/science.1254070
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发表时间：
2014-08-08
期刊：
影响因子：
56.9
通讯作者：
Strous, Marc
中科院分区：
文献类型：
--
作者：
Kraft, Beate;Tegetmeyer, Halina E.;Strous, Marc
在氮的生态地球化学循环中，微生物呼吸过程竞争硝酸盐作为电子受体。反硝化作用将硝酸盐转化为含氮气体，从而从生物圈中去除固定氮，而氨化作用将硝酸盐转化为铵，铵可直接由初级生产者重新使用。我们将海洋微生物硝酸盐呼吸群落的多个平行长期孵育与同位素标记和宏基因组学相结合，以揭示特定环境条件如何选择这两个过程。微生物的产生时间，供应的亚硝酸盐相对于硝酸盐，和碳/氮比被确定为关键的环境控制，确定是否亚硝酸盐将被还原为含氮气体或铵。我们的研究结果定义了微生物的生态生理的地球化学反馈回路，是全球变化，富营养化和废水处理的关键。
In the biogeochemical nitrogen cycle, microbial respiration processes compete for nitrate as an electron acceptor. Denitrification converts nitrate into nitrogenous gas and thus removes fixed nitrogen from the biosphere, whereas ammonification converts nitrate into ammonium, which is directly reusable by primary producers. We combined multiple parallel long-term incubations of marine microbial nitrate-respiring communities with isotope labeling and metagenomics to unravel how specific environmental conditions select for either process. Microbial generation time, supply of nitrite relative to nitrate, and the carbon/nitrogen ratio were identified as key environmental controls that determine whether nitrite will be reduced to nitrogenous gas or ammonium. Our results define the microbial ecophysiology of a biogeochemical feedback loop that is key to global change, eutrophication, and wastewater treatment.