Nitrogen Fixation and Diazotroph Community in the Subarctic Sea of Japan and Sea of Okhotsk
Nitrogen Fixation and Diazotroph Community in the Subarctic Sea of Japan and Sea of Okhotsk
复制标题
亚北极日本海和鄂霍次克海的固氮和固氮生物群落
DOI：
10.1029/2020jc017071
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Takahashi Kazutaka
中科院分区：
文献类型：
--
作者：
Sato Takuya;Shiozaki Takuhei;Taniuchi Yukiko;Kasai Hiromi;Takahashi Kazutaka
固氮微生物（固氮微生物）通过将氮气转化为生物可利用的氮来显着影响海洋生产力。最近的研究表明，固氮作用发生在温暖的寡营养水和较冷和/或富含氮的水中。然而，人们对冷水中固氮活性和固氮生物多样性的空间变异性知之甚少。在这项研究中，我们研究了日本北部北海道周围亚北极水域（包括日本海、鄂霍次克海和北太平洋）的固氮活性和固氮生物群落结构。在-1.1至15.6°C的温度范围内检测到固氮活性，并且与高盐度和高温显着相关，这是对马暖流的特征。最高记录的固氮活性（5.42 nmol N L−1d−1）与亚热带地区相当。通常在亚热带地区报道的固氮生物在固氮生物群落中占主导地位，很可能是从对马暖流（黑潮的支流）的上游地区平流而来。特别是，最主要的固氮生物——共生蓝细菌 UCYN-A1——的丰度与固氮率呈显着正相关。我们还在鄂霍次克海的富氮水域中检测到固氮生物群落和低但活跃的固氮作用，这推断了平流和本地固氮生物对区域固氮的影响。尽管还需要进一步的研究，但我们的研究表明鄂霍次克海存在着广泛的固氮生物分布。
Nitrogen‐fixing microorganisms (diazotrophs) significantly influence marine productivity by converting N2gas into bioavailable nitrogen. Recent studies revealed that nitrogen fixation occurs in both warm oligotroph and colder and/or N‐rich water; however, little is known about the spatial variability of nitrogen fixation activity and diazotroph diversity in cold waters. In this study, we examined the nitrogen fixation activity and diazotroph community structure in the subarctic waters around Hokkaido in northern Japan, including the Sea of Japan, the Sea of Okhotsk, and the North Pacific Ocean. Nitrogen fixation activity was detected at temperatures ranging from −1.1 to 15.6°C and was significantly related to high salinity and high temperature, which characterize the Tsushima Warm Current. The highest recorded nitrogen fixation activity (5.42 nmol N L−1d−1) was comparable to that of subtropical regions. Diazotrophs usually reported in subtropical regions dominated the diazotroph communities and were likely advected from the upstream area of the Tsushima Warm Current—a tributary of the Kuroshio Current. In particular, thenifHabundance of the most dominant diazotroph—the symbiotic cyanobacterium UCYN‐A1—showed a significant positive relationship with nitrogen fixation rate. We also detected a diazotroph community and low but active nitrogen fixation in the N‐rich waters sourced from the Sea of Okhotsk, which infers the influence of both advected and indigenous diazotrophs on the regional nitrogen fixation. Although further research is needed, our study points toward the widespread distribution of diazotrophy in the Sea of Okhotsk.