Biological nitrogen fixation in the oxygen-minimum region of the eastern tropical North Pacific ocean
Biological nitrogen fixation in the oxygen-minimum region of the eastern tropical North Pacific ocean
复制标题
热带北太平洋东部缺氧区的生物固氮
DOI：
10.1038/ismej.2017.97
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
B. Ward
中科院分区：
文献类型：
--
作者：
A. Jayakumar;B. Chang;Brittany Widner;P. Bernhardt;M. Mulholland;B. Ward
研究了北太平洋东部热带低氧带贫氧水域的生物固氮作用。利用同位素示踪剂方法估算了BNF率，该方法克服了传统气泡法的不确定性，直接测量了孵育过程中示踪剂的富集程度。BNF的最高检出率（~4 nM day - 1）出现在沿海地表水，最低检出率（~0.2 nM day - 1）出现在近海监测站的缺氧区。在大多数缺氧水域的样本中检测不到BNF。通过对nifH基因的测序，研究了n2固定组合的组成。地表水重氮营养化组合主要包含变形菌群序列（I簇nifH），而在缺氧水体中发现变形菌群序列和与厌氧微生物序列高度同源的序列，其特征为III簇和IV型nifH序列。我们的研究结果表明，在缺氧区，适度的氮输入主要是由于重氮营养菌的活性。
Biological nitrogen fixation (BNF) was investigated above and within the oxygen-depleted waters of the oxygen-minimum zone of the Eastern Tropical North Pacific Ocean. BNF rates were estimated using an isotope tracer method that overcame the uncertainty of the conventional bubble method by directly measuring the tracer enrichment during the incubations. Highest rates of BNF (~4 nM day−1) occurred in coastal surface waters and lowest detectable rates (~0.2 nM day−1) were found in the anoxic region of offshore stations. BNF was not detectable in most samples from oxygen-depleted waters. The composition of the N2-fixing assemblage was investigated by sequencing of nifH genes. The diazotrophic assemblage in surface waters contained mainly Proteobacterial sequences (Cluster I nifH), while both Proteobacterial sequences and sequences with high identities to those of anaerobic microbes characterized as Clusters III and IV type nifH sequences were found in the anoxic waters. Our results indicate modest input of N through BNF in oxygen-depleted zones mainly due to the activity of proteobacterial diazotrophs.
DOI：
10.1038/ismej.2014.71
发表时间：
2014-05
期刊：
The ISME Journal
影响因子：
--
作者：
C. Loescher;T. Grosskopf;Falguni Desai;D. Gill;H. Schunck;P. Croot;C. Schlosser;S. Neulinger;N. Pinnow;G. Lavik;M. Kuypers;J. LaRoche;R. Schmitz
通讯作者：
C. Loescher;T. Grosskopf;Falguni Desai;D. Gill;H. Schunck;P. Croot;C. Schlosser;S. Neulinger;N. Pinnow;G. Lavik;M. Kuypers;J. LaRoche;R. Schmitz
影响因子：
64.8
作者：
Grosskopf, Tobias;Mohr, Wiebke;LaRoche, Julie
通讯作者：
LaRoche, Julie