College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai, 201306, China; East China Sea Fisheries Research Institute, Shanghai, 200090, China.
Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, 4648601, Japan.
Harmful Algae. 2019 Feb;82:35-43. doi: 10.1016/j.hal.2018.12.007. Epub 2019 Feb 20.
The potential interactions between the bloom-forming dinoflagellates and other phytoplankton during the algal bloom cycle are interesting, while the causes for the phytoplankton community changes were not fully understood. We hypothesized that phytoplankton community structure and photosynthetic activities of total phytoplankton have their special characteristics in different phases of the algal blooms. To test this hypothesis, a survey covering the process of a Prorocentrum donghaiense bloom in coastal waters between Dongtou and Nanji Islands was carried out from 9 to 20 May 2016, and the changes in the phytoplankton community and photosynthetic activities of total phytoplankton were determined. Surface seawater was sampled for microscopic analysis of phytoplankton composition and pulse amplitude modulated (PAM) chlorophyll fluorescence analysis of photosynthetic activities of the total phytoplankton species. A total of 25, 31, and 19 phytoplankton species were identified in its growth (9-12 May), maintenance (13-18 May) and dissipation phases (19-20 May), respectively. Diatoms were dominant in terms of species number while dinoflagellates were predominant at cell abundance. Dinoflagellates were the major dominant species during three phases of the bloom based on the dominance (Y) value, whereas the dominant species extended to dinoflagellates and diatoms including P. donghaiense, Coscinodiscus argus, Gonyaulax spinifera, Cyclotella sp. and Scrippsiella trochoidea in the dissipation phase. In the maintenance phase, the average cell abundances of the total phytoplankton and P. donghaiense were consistent with the chlorophyll a (Chla) concentration in the seawater; for the diversity indices of total phytoplankton species, Simpson index (C) was the highest while Shannon index (H') and Pielou evenness index (J') were the lowest. Furthermore, photosynthetic activities of the total phytoplankton species represented by the effective quantum yield (F'/F') and the maximum relative electron transport rate (rETR) in the maintenance phase were higher than those in the growth and dissipation phases. The results indicated that the characteristics of phytoplankton community structure and photosynthetic activities could be regarded as criteria in predicting the phases of algal blooms.
在藻类繁殖周期中，形成水华的甲藻与其他浮游植物之间的潜在相互作用很有趣，而浮游植物群落变化的原因尚不完全清楚。我们假设浮游植物群落结构和总浮游植物的光合作用在水华的不同阶段具有其特殊的特征。为了验证这一假设，我们于 2016 年 5 月 9 日至 20 日在东头岛和南麂岛之间的沿海海域对东海原甲藻水华的整个过程进行了调查，并测定了浮游植物群落和总浮游植物光合作用的变化。采集表层海水进行浮游植物组成的显微镜分析和总浮游植物种类的脉冲幅度调制（PAM）叶绿素荧光分析。在其生长阶段（9-12 日）、维持阶段（13-18 日）和消散阶段（19-20 日）分别鉴定出浮游植物物种 25、31 和 19 种。从物种数量来看，硅藻占优势，而从细胞丰度来看，甲藻占优势。基于优势值（Y 值），甲藻是水华三个阶段的主要优势种，而在消散阶段，优势种扩展到包括东海原甲藻、角毛藻、夜光藻、旋链角毛藻和拟旋链角毛藻在内的甲藻和硅藻。在维持阶段，总浮游植物和东海原甲藻的平均细胞丰度与海水中的叶绿素 a（Chla）浓度一致；对于总浮游植物物种多样性指数，辛普森指数（C）最高，香农指数（H'）和皮埃罗均匀度指数（J'）最低。此外，在维持阶段，以有效量子产量（F'/F'）和最大相对电子传递率（rETR）表示的总浮游植物物种的光合作用活性高于生长和消散阶段。结果表明，浮游植物群落结构和光合作用活性的特征可以作为预测水华阶段的标准。
