Responses of phytoplankton assemblages to iron availability and mixing water masses during the spring bloom in the Oyashio region, NW Pacific
Responses of phytoplankton assemblages to iron availability and mixing water masses during the spring bloom in the Oyashio region, NW Pacific
复制标题
DOI：
10.1002/lno.11031
复制
发表时间：
2018-10
影响因子：
4.5
通讯作者：
Tomonori Isada;Ai Hattori-Saito;H. Saito;Y. Kondo;Y. Kondo;J. Nishioka;K. Kuma;H. Hattori;R. McKay;Koji Suzuki
中科院分区：
文献类型：
--
作者：
Tomonori Isada;Ai Hattori-Saito;H. Saito;Y. Kondo;Y. Kondo;J. Nishioka;K. Kuma;H. Hattori;R. McKay;Koji Suzuki
春季浮游植物水华在西亚北极太平洋Oyashio地区的碳地球化学循环中起着重要作用，该地区对海水pCO 2的季节性生物下降效应是世界海洋中最大的。然而，水华往往在大量营养素耗尽之前终止，并且水华的开始和大小是异质的。我们进行了高分辨率的浮游植物的分类和生理评估有关的不同物理化学水团的沿海Oyashio水（COW），Oyashio水（OYW），并修改黑潮水（MKW）在Oyashio地区从2007年4月至6月。4月发现大量硅藻水华。叶绿素a浓度、硅藻细胞丰度和最大光系统II光化学效率（Fv/Fm）与COW的混合比呈正相关，表明4月份春季水华受COW入侵的强烈影响。在OYW中，从5月中旬开始，在低溶解铁（DFe）浓度（< 0.26 nM）下发生了密集的水华。红细胞分析表明，虽然硅藻水华伴随着COW与DFe浓度有关，这是不是在OYW的情况。这些结果表明，硅藻在OYW具有不同的铁适应策略相比，硅藻在受COW影响的水团。这导致了Oyashio春季水华的空间异质性。这里提出的结果表明，水团特征与浮游植物分类和生理状态的详细评估，可以提高我们对海洋生态系统的理解。
Spring phytoplankton blooms play a major role in the carbon biogeochemical cycle of the Oyashio region, western subarctic Pacific, where the seasonal biological drawdown effect on seawater pCO2 is one of the greatest among the world's oceans. However, the bloom often terminates before depleting macronutrients, and the initiation and magnitude of the bloom is heterogeneous. We conducted a high resolution taxonomic and physiological assessment of phytoplankton in relation to the different physicochemical water masses of Coastal Oyashio Water (COW), Oyashio water (OYW), and modified Kuroshio water (MKW) in the Oyashio region from April to June 2007. Massive diatom blooms were found in April. Then, chlorophyll a concentration, cell abundance of diatom taxa, and the maximum photosystem II photochemical efficiency (Fv/Fm) were positively correlated with the mixing ratios of COW, suggesting that the spring bloom in April was strongly affected by the intrusion of COW. In the OYW, intensive blooms occurred from the middle of May under low dissolved iron (DFe) concentration (< 0.26 nM). Redundancy analysis showed that while diatom blooms accompanied by COW were related to DFe concentration, this was not the case in the OYW. These results indicated that diatoms in the OYW possess different iron adaptation strategies compared with diatoms in the water masses affected by COW. This led to the spatial heterogeneity of the Oyashio spring bloom. The results presented here demonstrate that water mass characterization with detailed assessments of phytoplankton taxonomy and physiological status can improve our understanding of marine ecosystems.