杭州湾——舟山渔场秋季浮游植物现存量和初级生产力

Primary productivity and standing stock of the phytoplankton in the Hangzhou Bay to the Zhoushan Fishing Ground during autumn

1995年 9月在杭州湾和长江口至舟山海区进行了浮游植物细胞丰度、叶绿素a浓度和初级生产力的现场观测研究 .结果表明 ,表层水浮游植物平均细胞丰度为(2 2 6 8± 6 3 33)× 1 0 4个 /dm3;平均叶绿素a浓度为 2 80± 3 46 μg/dm3,小于 2 0μm的微型和微微型浮游生物细胞对叶绿素a的贡献占 71 % ;平均初级生产力 (C)为6 92 5± 1 1 92 4mg/ (m2 ·d) ,小于 2 0 μm的微型和微微型浮游生物细胞对总生产力的贡献占 6 8% .河口区悬浮物质浓度高 ,浮游植物光合作用受光的限制 ,各项生物参数与真光层深度紧密相关 .生物锋区位于真光层深度 1 0～ 2 0m、盐度 2 6～ 32的长江冲淡水稀释区 .同时探讨了浮游植物细胞活性 (R)与光合作用同化数 (AN)、叶绿素a与初级生产力、叶绿素a与海面光谱反射率的相互关系 。

The observations on the cell abundance, chlorophyll a concentration and productivity of phytoplankton were carried out in the Hangzhou Bay and the Changjiang Estuary to the Zhoushan Fishing Ground during the autumn of 1995. The results show that the average cell abundance is (22.68×10 4±63.33×10 4) cell/dm 3 in the surface water of the survey area; average chlorophyll a is (2.80±3.46) μg/dm 3 and primary productivity is (692.5± 1 192.4 ) mg/(m 2·d) (C). The size fractionated chlorophyll a shows that nanoplankton and picoplankton with cell being less than 20 μm account for 71%, and they contribut to total productivity for dominant position (68%). This provs the importance of nano and picoplankton in phytoplankton community. The photosynthesis of phytoplankton is limited by light, as there is higher suspended particulate in the estuary. The correlation of the biological parameters with euphotic depth is significance in the survey area. The phytoplankton front is situated in the Changjiang Estuary dilution water where the euphotic depth is 10～20 m, salinity is 26～32.