Net Community Production, Dissolved Organic Carbon Accumulation, and Vertical Export in the Western North Atlantic
Net Community Production, Dissolved Organic Carbon Accumulation, and Vertical Export in the Western North Atlantic
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DOI：
10.3389/fmars.2020.00227
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发表时间：
2020-04-30
影响因子：
3.7
通讯作者：
Carlson, Craig A.
中科院分区：
文献类型：
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作者：
Baetge, Nicholas;Graff, Jason R.;Carlson, Craig A.
一年一度的北大西洋浮游植物水华是生物活动的热点，在此期间，很大一部分净群落生产量(NCP)可以被分解为溶解有机碳(DOC)。没有被异养细菌群落呼吸并在表层以季节过剩DOC(Delta DOC)形式累积的季节性NCP部分代表了DOC输出到中层上层的潜力，在北大西洋，这是由于冬季对流混合可以延伸到400米深处。然而，对北大西洋西部Delta DOC和垂直DOC输出的估计仍然不受限制，浮游植物群落结构对季节性NCP作为Delta DOC分配的影响尚未得到解决。在这里，作为北大西洋气溶胶和海洋生态系统研究(NAAMES)的一部分，我们将来自自主现场传感器(Argo Floats)的水文特性与来自晚春(类似于北纬44-56度，沿类似于-41度VV)和初秋(类似于北纬42-53度，沿类似于-41度)的两个经向断面的生物地球化学数据结合在一起。我们估计，在北大西洋西部的温带和亚极地，4-35%的季节性NCP被划分为Delta DOC，DOC的年垂直输出量在0.34-1.15molCm(-2)之间。两条证据表明，非硅质微藻浮游植物，如原球藻，是控制DOC积累和NCP分配为Delta DOC的条件的指示性物种。
The annual North Atlantic phytoplankton bloom represents a hot spot of biological activity during which a significant fraction of net community production (NCP) can be partitioned into dissolved organic carbon (DOC). The fraction of seasonal NCP that is not respired by the heterotrophic bacterial community and accumulates as seasonal surplus DOC (Delta DOC) in the surface layer represents DOC export potential to the upper mesopelagic zone, and in the North Atlantic this is facilitated by winter convective mixing that can extend to depths > 400 m. However, estimates of Delta DOC and vertical DOC export for the western North Atlantic remain ill-constrained and the influence of phytoplankton community structure on the partitioning of seasonal NCP as Delta DOC is unresolved. Here, we couple hydrographic properties from autonomous in situ sensors (ARGO floats) with biogeochemical data from two meridional transects in the late spring (similar to 44-56 degrees N along similar to -41 degrees VV) and early autumn (similar to 42-53 degrees N along similar to -41 degrees W) as part of the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). We estimate that 4-35% of seasonal NCP is partitioned as Delta DOC and that annual vertical DOC export ranges between 0.34 and 1.15 mol C m(-2) in the temperate and subpolar western North Atlantic. Two lines of evidence reveal that non-siliceous picophytoplankton, like Prochiorococcus, are indicator species of the conditions that control the accumulation of DOC and the partitioning of NCP as Delta DOC.