Nitrite and nitrate reduction drive sediment microbial nitrogen cycling in a eutrophic lake.
Nitrite and nitrate reduction drive sediment microbial nitrogen cycling in a eutrophic lake.
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DOI：
10.1016/j.watres.2022.118637
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发表时间：
2022-05
期刊：
影响因子：
12.8
通讯作者：
Dandan Zhang;Mingyue Li;Yuchun Yang;Huang Yu;Fanshu Xiao;Cheng R. Mao;Jie Huang;Yuhe Yu
中科院分区：
文献类型：
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作者：
Dandan Zhang;Mingyue Li;Yuchun Yang;Huang Yu;Fanshu Xiao;Cheng R. Mao;Jie Huang;Yuhe Yu
湖泊沉积物中厌氧微生物脱氮是湖泊生态系统氮循环的重要驱动过程之一。然而，湖泊沉积物中的硝化和厌氧氨氧化（anammox）细菌调控的氮去除及其机制仍然知之甚少。以东湖为研究对象，采用nirS/KandhzsB基因测序技术，对东湖不同湖区的底泥中的厌氧氨氧化细菌和反硝化细菌进行了研究。结果表明，沉积物中的反硝化细菌分属于9个类群，它们既参与异养反硝化作用，又参与自养反硝化作用。而厌氧氨氧化菌仅以刺孢属的优势菌为主。我们发现，NO3-和NO2-的浓度，以及Nar酶活性的关键因素影响的反硝化和厌氧氨氧化物群落在这个富营养化的湖泊。在生物反应器中的富集实验证实了反硝化和厌氧氨氧化速率的分歧与额外的补充NO2−，特别是在低硝酸还原酶活性的条件下。耦合反硝化和厌氧氨氧化可能在氮去除中起重要作用，电子受体（即，NO2-和NO3-）对湖泊沉积物中N的流失有很大影响。进一步的通径分析表明，NO2-、NO3-和一些氮相关酶是影响湖泊沉积物微生物脱氮的关键因子。本研究进一步加深了对湖泊沉积物反硝化和厌氧氨氧化的驱动机制的认识，为富营养化湖泊生态系统中反硝化-厌氧氨氧化脱氮耦合提供了新的视角。
The anaerobic microbial nitrogen (N) removal in lake sediments is one of the most important processes driving the nitrogen cycling in lake ecosystems. However, the N removal and its underlying mechanisms regulated by denitrifying and anaerobic ammonia oxidation (anammox) bacteria in lake sediments remain poorly understood. With the field sediments collected from different areas of Lake Donghu (a shallow eutrophic lake), we examined the denitrifying and anammox bacterial communities by sequencing thenirS/KandhzsBgenes, respectively. The results indicated that denitrifiers in sediments were affiliated to nine clusters, which are involved in both heterotrophic and autotrophic denitrification. However, anammox bacteria were only dominated byCandidatusBrocadia. We found that NO3−and NO2−concentrations, as well as Nar enzyme activity were the key factors affecting denitrifying and anammox communities in this eutrophic lake. The enrichment experiments in bioreactors confirmed the divergence of denitrification and anammox rates with an additional complement of NO2−, especially under a condition low nitrate reductase activity. The coupled denitrification and anammox may play significant roles in N removal, and the availability of electronic acceptors (i.e., NO2−and NO3−) strongly influenced the N loss in lake sediments. Further path analysis indicated that NO2−, NO3−and some N-related enzymes were the key factors affecting microbial N removal in lake sediments. This study advances our understanding of the mechanisms driving the of denitrification and anammox in lake sediments, which also provides new insights into coupled denitrification-anammox N removal in eutrophic lake ecosystems.