Diazotroph community structure and the role of nitrogen fixation in the nitrogen cycle in the Chukchi Sea (western Arctic Ocean)
Diazotroph community structure and the role of nitrogen fixation in the nitrogen cycle in the Chukchi Sea (western Arctic Ocean)
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DOI：
10.1002/lno.10933
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发表时间：
2018-09-01
影响因子：
4.5
通讯作者：
Hamasaki, Koji
中科院分区：
文献类型：
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作者：
Shiozaki, Takuhei;Fujiwara, Amane;Hamasaki, Koji
海洋固氮作用不仅发生在亚热带和热带地区，也发生在较寒冷的地区。然而，北冰洋的固氮生物分布、固氮速率及其对氮循环的贡献仍然鲜为人知。我们在2015年夏末对北冰洋西部楚科奇海的陆架和陆架外区域的固氮生物群落结构和活性进行了研究。同时测定了硝酸盐和铵的同化速率，以深入了解固氮作用在该区域氮循环中的作用。通过Illumina测序确定的固氮生物群落主要由第三类nifH型（假定的厌氧菌）组成，除了一个表层样本外，占所检测到的总序列的80%以上。这一结果与之前在其他海洋区域的发现截然不同。除第三类之外的nifH序列大多与UCYN - A2（共生蓝藻）有关，其占……
Marine nitrogen fixation occurs not only in subtropical and tropical regions but also in colder regions. However, the distribution of diazotrophs, nitrogen fixation rate, and its contribution to the nitrogen cycle in the Arctic Ocean remain poorly understood. We examined the diazotroph community structure and activity in the shelf and off-shelf regions of the Chukchi Sea, western Arctic Ocean, during late summer 2015. The nitrate and ammonium assimilation rates were determined simultaneously to gain insights into the role of nitrogen fixation in the nitrogen cycle of the region. The diazotroph community determined by Illumina sequencing was mainly composed of Cluster III nifH phylotypes (putative anaerobes), accounting for>80% of the total sequences examined, except for one surface sample. This result is strikingly different from previous findings in other oceanic regions. The nifH sequences other than those from Cluster III were mostly affiliated with UCYN-A2 (symbiotic cyanobacteria), which accounted for