Spring phytoplankton blooms in the Northern Satsunan region, Japan, stimulated by the intrusion of Kuroshio Branch water
Spring phytoplankton blooms in the Northern Satsunan region, Japan, stimulated by the intrusion of Kuroshio Branch water
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DOI：
10.1016/j.ecss.2021.107472
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发表时间：
2021-09
影响因子：
2.8
通讯作者：
Tomohiro Komorita;T. Kobari;G. Kume;Daiki Sawada;Takuya Nagata;Akimasa Habano;Yoichi Arita;Fumihiro Makino;Mutsuo Ichinomiya
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文献类型：
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作者：
Tomohiro Komorita;T. Kobari;G. Kume;Daiki Sawada;Takuya Nagata;Akimasa Habano;Yoichi Arita;Fumihiro Makino;Mutsuo Ichinomiya
黑潮对沿岸地区的生物过程有很大的影响。鹿儿岛湾有良好的产卵场主要洄游鱼类，作为一个重要的喂养区的鱼苗，并受到黑潮电流，但是，有很少的信息有关的生物反应的黑潮入侵在这个位置。在混合期，黑潮向鹿儿岛湾靠近，产生了由表层入流和底层出流组成的异重流。我们假设，在海湾的底层水，具有较高的营养盐浓度，与表层混合时，水流出海湾，这有助于在湾口的高生物生产。在这项研究中，我们在2016年3月进行了一次水质实地调查，并使用三端元混合模型，研究了海湾的底层水是否可以成为支持海湾口浮游植物水华的营养源。我们讨论的命运的有机质来自初级生产促进营养供应事件。结果表明，氮为基础的浮游植物生物量的浮游植物的氮吸收量小于80%，估计通过减去测量的硝酸盐浓度从供应的硝酸盐浓度的基础上的混合模型，表明浮游植物水华在湾口的底层水的供应支持。根据本研究中的C/Chl-a和N/Chl-ain计算的C/N摩尔比（6.4），就碳同化而言，氮吸收的最高值为12 mg Cm −3d− 1。根据生理模型，中型浮游动物的摄食率估计为13.6 mg C m−3d− 1。食物网结构的分析是必需的，以评估由中型浮游动物喂养的影响，但是，混合引起的浮游植物水华大部分可以有效地转移到中型浮游动物在本研究区。
The Kuroshio current greatly affects biological processes in coastal areas. The Kagoshima Bay has good spawning ground for major migratory fish, serves as an important feeding area for fish larvae, and is affected by the Kuroshio current; however, there is little information concerning the biological response to the Kuroshio intrusion in this location. During the mixing period, the Kuroshio current approaches the Kagoshima Bay and a density flow, consisting of surface inflow and bottom outflow, is generated. We hypothesize that the bottom water in the bay, having a high nutrient concentration, mixes with the surface layer when the water flows out of the bay and that this contributes to the high biological production at the bay mouth. In this study, we conducted a field survey of the water quality in March 2016 and, using a three-end member mixing model, examined whether the bottom water of the bay could be a nutrient source supporting the phytoplankton bloom in the bay mouth. We discuss the fate of the organic matter derived from the primary production promoted by a nutrient supply event. The results indicate that the N-based phytoplankton biomass represented less than 80% of the N uptake by the phytoplankton, as estimated by subtracting the measured nitrate concentration from the supplied nitrate concentration based on the mixing model, indicating that the phytoplankton bloom at the bay mouth was supported by the supply of bottom water from the bay. Based on the C/N molar ratio (6.4) calculated by C/chlorophylla(Chl-a) and N/Chl-ain this study, the highest value of nitrogen uptake was 12 mg C m−3d−1in terms of the carbon assimilation. The feeding rate of the mesozooplankton was estimated to be 13.6 mg C m−3d−1using a physiological model. An analysis of the food web structure is required to assess the effects of feeding by mesozooplankton; however, most of the phytoplankton bloom caused by mixing could be efficiently transferred to mesozooplankton in this study area.