Environmental controls on the biogeography of diazotrophy and Trichodesmium in the Atlantic Ocean
Environmental controls on the biogeography of diazotrophy and Trichodesmium in the Atlantic Ocean
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DOI：
10.1002/2015gb005090
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发表时间：
2015-06
影响因子：
5.2
通讯作者：
Joseph T. Snow;Christian Schlosser;E. Malcolm S. Woodward;Matthew M. Mills;E. Achterberg;C. Mahaffey;T. Bibby;C. M. Moore
中科院分区：
文献类型：
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作者：
Joseph T. Snow;Christian Schlosser;E. Malcolm S. Woodward;Matthew M. Mills;E. Achterberg;C. Mahaffey;T. Bibby;C. M. Moore
蓝细菌Trichodesmium是每年引入全球海洋的“新”氮的重要组成部分。尽管可以说是研究最好的海洋固氮生物，但控制束毛藻分布和生长的因素仍然是一个争论的主题，海面温度，二氧化碳分压，以及营养物质，包括铁（Fe）和磷（P），都被认为是重要的。综合数据从七个邮轮集体跨越大的时间和空间尺度横跨大西洋，包括两个以前未报告的研究跨越大部分采样不足的南大西洋环流，我们评估了拟议的环境驱动因素和两个社区N2固定率和束毛藻的分布之间的关系。简单的线性回归分析表明，任何采样的环境变量和固氮率之间没有关系。然而，考虑到铁和磷的浓度在一个简化的资源比框架内，说明使用理想化的数值模型，表明这些营养物质的综合影响，对束毛藻和更广泛的固氮生物地理，以及相互维护的不同的（亚）热带大西洋的固氮生物地理省的铁或磷贫营养状态。资源比率框架的定性原则被认为是与先前描述的北大西洋束毛藻丰度的对比以及在南大西洋西部亚热带环流中大量非束毛藻重氮营养群落的存在和后果相一致的。因此，揭示了Trichodesmium和大西洋更广泛的重氮营养群落与铁和磷之间相互作用的全面，基于观察的解释。
The cyanobacterium Trichodesmium is responsible for a significant proportion of the annual “new” nitrogen introduced into the global ocean. Despite being arguably the best studied marine diazotroph, the factors controlling the distribution and growth of Trichodesmium remain a subject of debate, with sea surface temperature, the partial pressure of CO2, and nutrients including iron (Fe) and phosphorus (P), all suggested to be important. Synthesizing data from seven cruises collectively spanning large temporal and spatial scales across the Atlantic Ocean, including two previously unreported studies crossing the largely undersampled South Atlantic gyre, we assessed the relationship between proposed environmental drivers and both community N2 fixation rates and the distribution of Trichodesmium. Simple linear regression analysis would suggest no relationship between any of the sampled environmental variables and N2 fixation rates. However, considering the concentrations of iron and phosphorus together within a simplified resource‐ratio framework, illustrated using an idealized numerical model, indicates the combined effects these nutrients have on Trichodesmium and broader diazotroph biogeography, alongside the reciprocal maintenance of different biogeographic provinces of the (sub)tropical Atlantic in states of Fe or P oligotrophy by diazotrophy. The qualitative principles of the resource‐ratio framework are argued to be consistent with both the previously described North‐South Atlantic contrast in Trichodesmium abundance and the presence and consequence of a substantial non‐Trichodesmium diazotrophic community in the western South Atlantic subtropical gyre. A comprehensive, observation‐based explanation of the interactions between Trichodesmium and the wider diazotrophic community with iron and phosphorus in the Atlantic Ocean is thus revealed.