Nutrient regulation of late spring phytoplankton blooms in the midlatitude North Atlantic
Nutrient regulation of late spring phytoplankton blooms in the midlatitude North Atlantic
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DOI：
10.1002/lno.11376
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发表时间：
2019-11-19
影响因子：
4.5
通讯作者：
Achterberg, Eric P.
中科院分区：
文献类型：
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作者：
Browning, Thomas J.;AI-Hashem, Ali A.;Achterberg, Eric P.
北大西洋春季盛开的持续时间和幅度会影响较高的营养水平和海洋碳固执。营养精疲力尽提供了关于花朵终止的一般解释，但缺乏营养素及其对浮游植物生产力，社区结构和生理学的相对影响的细节。在这里，我们使用在2017年6月（春末）遍布北大西洋中部的北纬度地区进行的营养添加生物测定实验来解决此问题。在六个实验中的四个中，浮游植物在单个添加铁（Fe）或氮（n）的添加后，浮游植物积累了48-72 h。在其余两个实验中，Fe和N在序列上限制，即它们的组合添加依次增强的浮游植物积累。与N + Fe结合添加的硅酸（SI）导致了两个部位的进一步叶绿素A（CHL A）增强。相反，与N + Fe结合使用锌，锰，钴，维生素B-12或磷酸盐。在两个地点，所有六种营养素的同时供应与N + Fe结合在一起，也没有进一步的增强，但确实导致了30-60％的颗粒碳积累。这种颗粒碳的积累与颗粒n等效的红场不匹配，颗粒n的特征是高c：n有机渗出液，可增强细胞聚集和下沉。我们的结果表明，较大的浮游植物的增长率主要受到FE和/或N的限制，这使得这些营养素的可用性是促成春季开花终止的主要自下而上因素。此外，其他营养素的同时可用性可以改变开花特性和碳出口效率。
The duration and magnitude of the North Atlantic spring bloom impacts both higher trophic levels and oceanic carbon sequestration. Nutrient exhaustion offers a general explanation for bloom termination, but detail on which nutrients and their relative influence on phytoplankton productivity, community structure, and physiology is lacking. Here, we address this using nutrient addition bioassay experiments conducted across the midlatitude North Atlantic in June 2017 (late spring). In four out of six experiments, phytoplankton accumulated over 48-72 h following individual additions of either iron (Fe) or nitrogen (N). In the remaining two experiments, Fe and N were serially limiting, that is, their combined addition sequentially enhanced phytoplankton accumulation. Silicic acid (Si) added in combination with N + Fe led to further chlorophyll a (Chl a) enhancement at two sites. Conversely, addition of zinc, manganese, cobalt, vitamin B-12, or phosphate in combination with N + Fe did not. At two sites, the simultaneous supply of all six nutrients, in combination with N + Fe, also led to no further Chl a enhancement, but did result in an additional 30-60% particulate carbon accumulation. This particulate carbon accumulation was not matched by a Redfield equivalent of particulate N, characteristic of high C:N organic exudates that enhance cell aggregation and sinking. Our results suggest that growth rates of larger phytoplankton were primarily limited by Fe and/or N, making the availability of these nutrients the main bottom-up factors contributing to spring bloom termination. In addition, the simultaneous availability of other nutrients could modify bloom characteristics and carbon export efficiency.