N-2 fixation impacted by carbon fixation via dissolved organic carbon in the changing Daya Bay, South China Sea
N-2 fixation impacted by carbon fixation via dissolved organic carbon in the changing Daya Bay, South China Sea
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南海大亚湾变化中溶解有机碳固碳对 N-2 固定的影响
DOI：
10.1016/j.scitotenv.2019.04.176
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发表时间：
2019
影响因子：
9.8
通讯作者：
Zheng Minfang
中科院分区：
文献类型：
--
作者：
Li Danyang;Liu Jiaxing;Zhang Run;Chen Min;Yang Weifeng;Li Junjie;Fang Ziming;Wang Bo;Qiu Yusheng;Zheng Minfang
我们提出了2015 - 2017年南海（NSCS）北方亚热带大亚湾（DB）的N2固定率（15 N2吸收）、初级生产力（14 C吸收）、溶解有机碳（DOC）浓度和固氮菌群落组成的首次同步测量结果。N2固定率范围为n.d. - 4.51 nmol N L−1h−1。这些值普遍高于在邻近的NSCS开放沃茨和几个研究充分的贫营养沃茨，从而表明，N-充分的条件下，不阻止N2固定在沿海沃茨。春季和夏季固定N2速率与初级生产力和DOC浓度呈显著正相关。结合其他证据，我们认为，N2固定可能是由非固氮浮游植物通过可能的调节DOC的数量和质量（生物利用度）DB。由于DB代表了一个合适的网站，经历了显着的人为引起的环境条件的变化，我们的研究结果可能提供见解，了解如何N2固定和相关的生物地球化学过程可能会对类似的沿海设置加强全球人为强迫。
We present the first concurrent measurements of N2fixation rates (15N2uptake), primary production (14C uptake), dissolved organic carbon (DOC) concentrations, and diazotrophic community composition derived from nitrogenase (nifH) abundance in the subtropical Daya Bay (DB) of the coastal northern South China Sea (NSCS) from 2015 to 2017. N2fixation rates ranged from n.d. - 4.51 nmol N L−1h−1. Such values were generally higher than those reported in the neighbouring NSCS open waters and several well-studied oligotrophic waters, thereby suggesting that N-replete conditions do not prevent N2fixation in coastal waters. N2fixation rates were positively and significantly correlated with the primary production and the concentration of DOC in DB in the spring and summer. Combined with other lines of evidence, we suggest that N2fixation may be facilitated by non-diazotrophic phytoplankton via a probable regulation of the quantity and quality (bioavailability) of DOC in DB. Since DB represents a suitable site that has experienced dramatic human-induced changes in environmental conditions, our results likely provide insights in understanding how N2fixation and relevant biogeochemical processes may respond to intensified global anthropogenic forcing in similar coastal settings.