Dynamics and controls of heterotrophic prokaryotic production in the western tropical South Pacific Ocean: links with diazotrophic and photosynthetic activity
Dynamics and controls of heterotrophic prokaryotic production in the western tropical South Pacific Ocean: links with diazotrophic and photosynthetic activity
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DOI：
10.5194/bg-15-2669-2018
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发表时间：
2018-05
期刊：
影响因子：
4.9
通讯作者：
A. Gimenez;S. Duhamel;C. Dupouy;D. Lefèvre;M. Pujo-Pay;T. Moutin
中科院分区：
文献类型：
--
作者：
A. Gimenez;S. Duhamel;C. Dupouy;D. Lefèvre;M. Pujo-Pay;T. Moutin
抽象。异养原核生产（BP）的研究在热带南太平洋西部（WTSP）使用亮氨酸技术，揭示了该地区的时空变化。在真光层上，美拉尼西亚群岛内的BP范围为58至120 mg C m −2 d −1，而在西副热带环流内的BP范围为31至50 mg C m −2 d −1。崩溃的水华，随后在6天内在瓦努阿图南部使用拉格朗日采样策略。在此期间，在影响代谢状态的三个主要参数中观察到快速演变：BP，初级生产（PP）和细菌生长效率。固氮是促进新生产的最重要的通量之一，我们探讨了BP，PP和固氮率之间的关系在WTSP。固氮速率对细菌需氮量的贡献在3 ~ 81%之间. BP的变异性更好地解释了N 2固定率的变化比PP在表面沃茨的美拉尼西亚群岛，其特点是N-贫化层和低DIP周转时间（TDIP 100小时），更深的美拉尼西亚群岛，或在整个真光区的亚热带环流。细菌需碳量与总初级生产力之比为0.75 ~ 3.1。这些值进行了讨论的框架内的各种假设和转换因子，用于估计这一比例，包括方法误差，BP的每日变化，细菌的生长效率和一个偏见，到目前为止没有考虑：原绿球藻同化亮氨酸在黑暗中的能力。
Abstract. Heterotrophic prokaryotic production (BP) was studied in the western tropical South Pacific (WTSP) using the leucine technique, revealing spatial and temporal variability within the region. Integrated over the euphotic zone, BP ranged from 58 to 120 mg C m −2 d −1 within the Melanesian Archipelago, and from 31 to 50 mg C m −2 d −1 within the western subtropical gyre. The collapse of a bloom was followed during 6 days in the south of Vanuatu using a Lagrangian sampling strategy. During this period, rapid evolution was observed in the three main parameters influencing the metabolic state: BP, primary production (PP) and bacterial growth efficiency. With N 2 fixation being one of the most important fluxes fueling new production, we explored relationships between BP, PP and N 2 fixation rates over the WTSP. The contribution of N 2 fixation rates to bacterial nitrogen demand ranged from 3 to 81 %. BP variability was better explained by the variability of N 2 fixation rates than by that of PP in surface waters of the Melanesian Archipelago, which were characterized by N-depleted layers and low DIP turnover times ( TDIP 100 h), deeper in the Melanesian Archipelago, or within the entire euphotic zone in the subtropical gyre. The bacterial carbon demand to gross primary production ratio ranged from 0.75 to 3.1. These values are discussed in the framework of various assumptions and conversion factors used to estimate this ratio, including the methodological errors, the daily variability of BP, the bacterial growth efficiency and one bias so far not considered: the ability for Prochlorococcus to assimilate leucine in the dark.