| 浮游植物群落及粒径结构对光吸收特性的影响 |
| 摘要点击 1898 全文点击 714 投稿时间：2020-07-31 修订日期：2020-08-17 |
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| 中文关键词 浮游植物吸收 群落结构 等效粒径(ESD) 丰度 生物量 天目湖 |
| 英文关键词 phytoplankton absorption community composition equivalent sphere diameter (ESD) biomass abundance Lake Tianmu |
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| 中文摘要 |
| 浮游植物吸收及比吸收等光学特性表征浮游植物对光的吸收能力，很大程度上决定了其光合作用效率和碳固定量，是浮游植物生态学、水体光学和水色遥感领域研究热点和前沿问题.本研究基于2013年天目湖7个固定采样点逐月观测数据，分析了浮游植物生物量、群落结构、吸收以及比吸收系数等生物-光学参数的季节变化特征，构建了浮游植物生物量、群落结构与吸收、比吸收的参数化关系，提出等效粒径指数概念并探讨其对浮游植物吸收和比吸收系数的影响机制.结果表明，天目湖浮游植物生物量和丰度秋季最高、冬季最低，群落结构季节演替明显，隐藻、针杆藻、小环藻为全年优势属，冬春季节优势属为硅藻-隐藻型，夏季为硅藻-绿藻-甲藻型，秋季为隐藻-硅藻-绿藻型；浮游植物等效粒径季节变化明显，表现为夏季 > 秋季 > 冬季 > 春季，夏季平均值为64.83 μm，春季平均值为29.54 μm.浮游植物吸收系数表现为秋季 > 春季 > 冬季 > 夏季，其中秋季浮游植物在440 nm和675 nm的吸收系数均值为（0.66±0.18） m-1和（0.33±0.10） m-1，夏季均值为（0.17±0.02） m-1和（0.08±0.01） m-1.浮游植物比吸收系数为春季 > 冬季 > 秋季 > 夏季，其中春季浮游植物在440 nm和675 nm的比吸收系数的均值为（0.07±0.02） m2·mg-1和（0.04±0.01） m2·mg-1，夏季的均值为（0.03±0.004） m2·mg-1和（0.01±0.002） m2·mg-1.浮游植物吸收系数随生物量和丰度的增加而线性升高，气温引起的硅藻、蓝藻丰度生物量的变化是引起浮游植物吸收系数季节变化的主要原因；比吸收系数和等效粒径呈线性负相关，浮游植物群落结构季节更替引起等效粒径的变化是影响浮游植物比吸收系数季节变化的重要因素. |
| 英文摘要 |
| In the fields of phytoplankton ecology, water optics, and water color remote sensing, phytoplankton absorption properties represent the light absorption capacity of phytoplankton, which affects photosynthesis efficiency and carbon fixation. Here, the biomass, community composition, and the absorption properties of phytoplankton were measured alongside other bio-optical parameters in Lake Tianmu are examined using data collected between January and November 2013 (except February). Based on the relationships between phytoplankton biomass, community composition, and absorption, the effects of abundance, biomass, and equivalent sphere diameter on phytoplankton absorption and specific absorption were revealed. The highest biomass and abundance of phytoplankton were recorded in the autumn and the lowest in the winter. Cryptomonas, Synedra, and Cyclotella were the dominant genera throughout the year. The dominant genera structure type was Bacillariophyta-Cryptophyta in the winter and spring, Bacillariophyta-Chlorophyta-Pyrroptata in the summer, and Cryptophyta-Bacillariophyta-Chlorophyta in the autumn. Phytoplankton diameter was ranked in the order summer>autumn>winter>spring, with mean values of 64.83 μm in summer and 29.54 μm in spring. Phytoplankton absorption coefficients of were ranked in the order autumn > spring > winter > summer, with mean values at 440 nm and 675 nm of (0.66±0.18) m-1 and (0.33±0.10) m-1 in autumn and (0.17±0.02) m-1 and (0.08±0.01) m-1 in summer, respectively. The specific absorption coefficients of the phytoplankton were ranked in the order spring > winter > autumn > summer, with mean values at 440 nm and 675 nm of (0.07±0.02) m2·mg-1 and (0.04±0.01) m2·mg-1 in spring and (0.03±0.004) m2·mg-1 and (0.01±0.002) m2·mg-1 in summer, respectively. Significant linear correlations were found between phytoplankton biomass, abundance, and absorption coefficients. Variations of Bacillariophyta and Cyanophyta biomass caused by temperature explained the seasonal variation in absorption coefficients. The specific absorption coefficient decreased with an increase in equivalent sphere diameter, and variations in phytoplankton community composition explained seasonal changes in the specific absorption coefficient. |
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