长江口疏浚弃土悬沙对2种浮游植物生长的影响

Effects of suspended dredging sediment on growth of 2 species of phytoplankton in the Changjiang estuary

长江口疏浚弃土悬沙对微绿球藻(Nannochloropsis oculata)和牟氏角毛藻(Chaetoceros muelleri)的生长有一定的抑制作用。试验结果表明,当水体中含沙量持续96 h 达到3 g/L 时,藻类生长速率降低20%～30%。但当疏浚作业停止,悬沙将迅速沉淀,水体变清,藻类生长可恢复正常。

Experimental results show that suspended dredging sediment inhibits the growth of Nannochloropsis oculata and Chaetoceros muelleri.When sediment amount is lower than 3 g/L and lasting 96 h,the growing rate of the algae reduces by 20%～30%.Once the dredging operation was stopped,the suspended sediment would sink and the water become clear quickly,then the algae growth would recover and turn to normal status gradually.