1996年德国石荷西部沿岸水域浮游植物种群变动及其整齐圆筛藻赤潮(英文)

Phytoplankton population dynamics and Coscinodiscus concinnus blooms in the west-coast water of Schleswig-Holstein,Germany in 1996

1 996年早春至初夏 ,德国石荷州西海岸水域尤其是在易白河河口附近海区发生了数次赤潮事件 ,河口区的高叶绿素浓度总是与低盐、高营养盐浓度的分布区吻合。从早春 3月至 5月底 ,发生了持续时间很长的大规模赤潮事件 ,其引发赤潮原因种为整齐圆筛藻 ,6月份对浮游植物生物量的贡献主要来自几种硅藻如微小细柱藻、聚生角毛藻、远洋角毛藻以及属于鞭毛藻类的棕囊藻群体 ,7月中旬 ,自养的纤毛虫类 Myrionecta rubra( Mesodinium rubrum)达到数量高峰。从 7月下旬至 8月中旬 ,以梭形角藻、叉状角藻占优势的甲藻类几乎贡献了全部的浮游植物生物量 ,8月中旬至 9月上旬为甲藻和硅藻等类别的混合期 ,9月中旬以后 ,硅藻重新占据浮游植物数量的绝对优势 ,主要优势种为浮动弯角藻、复瓦根管藻等 ,该海域浮游植物种群的演替反映了温带海域的特征。在早春发生的大规模赤潮期间 ,整齐圆筛藻的细胞密度达到2 1 80 cellsdm- 3,与之相对应的生物量为 758.1μg C dm- 3,占浮游植物生物量的 94 .2 % ,整齐圆筛藻的爆发性增殖所产生的大量油膜覆盖了黑尔果兰岛和东 Frisian群岛周围的海域 。

Several blooms occurred in spring and throughout the summer near the estuary of the Elbe River,the west coast water of Schleswig Holstein,in 1996.High Chl a concentration coincide very well with low salinity and total nitrate concentration.From early spring to the end of May,a strong and long lasting bloom,which was dominated by the large diatom Coscinodiscus concinnus, occurred in the waters along the west coast of Schleswig Holstein.In June,several diatoms such as Leptocylindrus minimus,Chaetoceros socialis,Cerataulina pelagica, and colonies of the flagellate Pheaocystis contributed to the biomass of phytoplankton.The autotrophic ciliate Myrionecta rubra(Mesodinium rubrum) reached its highest concentration in July.In the period of July to the middle of August,dinoflagellates were dominant represented by Ceratium fusus and Ceratium furca. In autumn,diatoms dominated again with species of Eucampia zodiacus and Rhizosolenia imbricata. The succession pattern of phytoplankton population in this area is a typical one in temperate waters.During the spring blooms,the highest density of Concinodiscus concinnus reached 2180 cells dm -3 and its peak biomass,which contributed 94.2% of total phytoplankton biomass,was 758.1 μg C dm -3 on March 27. The extensive bloom dominated by Concinodiscus concinnus in the waters around the island of Helgoland and in the waters along the coast of the East Frisian Islands resulted in producing oily film that covered the surface of the sea.This oil slick produced by this large diatom was first time to be detected by satellite remote sensing in its history.