Phytoplankton growth response to Asian dust addition in the northwest Pacific Ocean versus the Yellow Sea
Phytoplankton growth response to Asian dust addition in the northwest Pacific Ocean versus the Yellow Sea
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DOI：
10.5194/bg-15-749-2018
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发表时间：
2017-06
期刊：
影响因子：
4.9
通讯作者：
Chao Zhang;Huiwang Gao;X. Yao;Zongbo Shi;Jinhui Shi;Yang Yu;L. Meng;Xinyu Guo
中科院分区：
文献类型：
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作者：
Chao Zhang;Huiwang Gao;X. Yao;Zongbo Shi;Jinhui Shi;Yang Yu;L. Meng;Xinyu Guo
抽象的。在本研究中，在副热带环流，西北太平洋黑潮延伸区（NWPO）和黄海（YS）进行了五个船上的微型宇宙实验，以调查浮游植物生长的人工改性矿物粉尘（AM粉尘）和各种营养盐（N），磷（P），铁（Fe），N + P，N + P + Fe）。在亚热带环流中进行的两个实验显示，与对照组相比，AM粉尘的最大叶绿素a（Chl a）浓度增加了1.7倍和2.8倍，而大型浮游植物（> 5 µm）的细胞丰度分别增加了1.8倍和3.9倍。然而，在黑潮延伸区和YS，最大叶绿素a和大型浮游植物细胞丰度的增加后AM粉尘除了最多1.3倍和1.7倍以上，分别比对照组。一个净转换效率指数（NCEI）在这项研究中新提出的，粒度分级叶绿素a，和大型浮游植物的丰度进行了分析，以确定哪些营养物质有助于支持浮游植物的生长。我们的研究结果表明，营养盐的组合，N-P或N + P + Fe，是负责浮游植物生长的副热带环流后AM尘埃添加。单一营养添加，即，N在黑潮延伸区和P或N在YS，控制浮游植物的生长后AM粉尘添加。在添加AM粉尘的实验中，确定增加的N-P或P来确定浮游植物的生长，AM粉尘中溶解的无机P（8.6 nmol L−1）远低于理论估计的浮游植物生长的最低P需求（1020 nmol L−1）。这些观察结果表明，额外的供应增加了生物可利用的P股票在培养海水与AM灰尘除了，最有可能是由于增强的溶解度P从AM灰尘或溶解的有机P的磷酸化。
Abstract. In this study, five on-board microcosm experiments were performed in the subtropical gyre, the Kuroshio Extension region of the northwest Pacific Ocean (NWPO), and the Yellow Sea (YS) in order to investigate phytoplankton growth following the addition of artificially modified mineral dust (AM dust) and various nutrients (nitrogen (N), phosphorus (P), iron (Fe), N + P, and N + P + Fe). The two experiments carried out with AM-dust addition in the subtropical gyre showed a maximum chlorophyll a (Chl a) concentration increase of 1.7- and 2.8-fold, while the cell abundance of large-sized phytoplankton ( > 5 µm) showed a 1.8- and 3.9-fold increase, respectively, relative to the controls. However, in the Kuroshio Extension region and the YS, the increases in maximum Chl a and cell abundance of large-sized phytoplankton following AM-dust addition were at most 1.3-fold and 1.7-fold larger than those in the controls, respectively. A net conversion efficiency index (NCEI) newly proposed in this study, size-fractionated Chl a, and the abundance of large-sized phytoplankton were analysed to determine which nutrients contribute to supporting phytoplankton growth. Our results demonstrate that a combination of nutrients, N–P or N + P + Fe, is responsible for phytoplankton growth in the subtropical gyre following AM-dust addition. Single nutrient addition, i.e., N in the Kuroshio Extension region and P or N in the YS, controls the phytoplankton growth following AM-dust addition. In the AM-dust-addition experiments, in which the increased N–P or P was identified to determine phytoplankton growth, the dissolved inorganic P from AM dust (8.6 nmol L−1) was much lower than the theoretically estimated minimum P demand (∼ 20 nmol L−1) for phytoplankton growth. These observations suggest that additional supply augments the bioavailable P stock in incubated seawater with AM-dust addition, most likely due to an enhanced solubility of P from AM dust or the remineralization of the dissolved organic P.