Exhaustion of nitrate terminates a phytoplankton bloom in Funka Bay, Japan: change in SiO4:NO3 consumption rate during the bloom
Exhaustion of nitrate terminates a phytoplankton bloom in Funka Bay, Japan: change in SiO4:NO3 consumption rate during the bloom
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硝酸盐耗尽终止了日本丰卡湾的浮游植物水华：水华期间 SiO4:NO3 消耗率的变化
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
K. Matsunaga
中科院分区：
文献类型：
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作者：
I. Kudo;T. Yoshimura;M. Yanada;K. Matsunaga
时间序列观测超过36小时，在Funka湾，日本，补充6年的营养动态研究期间的硅藻春季水华，特别是专注于硝酸盐和硅酸盐限制营养。在研究开始时，营养盐浓度较高（NO3 = 10 μM，SiO4 = 20 μM和PO4 = 0.8 μM）。硝酸盐在夜间首先耗尽，而硅酸盐和磷酸盐分别保持在10和0.3 μM。高硝酸还原酶活性观察第二天早上，硝酸盐的同化原位占主导地位的phytophytoeros socialis。SiO4：NO3消耗比由盛花期前的0.83增加到盛花期后的2.5，增加了3倍。浮游植物的元素组成也发生了明显的变化，在水华高峰后，Si：C和Si：N比增加了2至4倍，而C：N比保持在7左右。由于SiO4和NO3的消耗速率的这种变化，硅酸盐和硝酸盐最终在透光层中耗尽。
Time series observations over 36 h were carried out in Funka Bay, Japan, to complement a 6 yr nutrient-dynamics study during a diatom spring bloom, especially focusing on nitrate and silicate as limiting nutrients. At the beginning of the study, nutrient concentrations were high (NO 3 = 10 μM, SiO 4 = 20 μM and PO 4 = 0.8 μM). Nitrate was depleted first during the night while silicate and phosphate remained at 10 and 0.3 μM, respectively. High nitrate reductase activity was observed the following morning, indicating the assimilation of nitrate in situ by the dominant phytoplankter, Chaetoceros socialis. The consumption ratio of SiO 4 :NO 3 increased by 3 times from 0.83 before the peak to 2.5 after the peak of the bloom. This change was also obvious in the elemental composition of phytoplankton, showing an increase in Si:C and Si:N ratios by a factor of 2 to 4 after the peak of the bloom, while C:N ratio remained constant at around 7. As a consequence of this change in the consumption rate of SiO 4 and NO 3 , both silicate and nitrate were finally depleted in the photic zone.