厦门岛西北海域浮游植物生物量粒级结构及其环境影响因素

Size-fractionated Biomass of Phytoplankton and Its Environmental Impact Factors in the Waters off Northwestern Xiamen Island

文章利用2018年9—11月厦门岛西北海域的现场调查资料,在对海域水质污染状况和富营养化水平进行评价的基础上,分析并讨论浮游植物生物量粒级结构及其环境影响因素。研究结果表明:同安湾在11月处于富营养水平,属于中度或严重污染海域;九龙江口和西海域在9-11月均处于磷中等限制潜在性富营养或磷限制潜在性富营养水平,属于严重污染海域。同安湾和西海域浮游植物分粒级的生物量占比与九龙江口存在明显差异,前者由大到小依次为微型、小型、微微型,后者由大到小依次为小型、微型、微微型。小型浮游植物生物量与硝酸盐和亚硝酸盐、溶解无机氮、溶解无机磷以及活性硅酸盐呈显著正相关,与盐度呈显著负相关;微型浮游植物生物量与真光层深度、铵盐和溶解无机磷呈显著正相关;微微型浮游植物生物量与真光层深度、铵盐和溶解无机磷呈显著正相关,与pH值呈显著负相关。影响浮游植物群落粒级结构的最重要的海洋环境因子是盐度、真光层深度和溶解无机磷,尤其是溶解无机磷浓度,其值一旦升高,浮游植物极有可能从磷胁迫状态发展为赤潮。控制排污、实时监控、增强预警能力和改善生态环境是控制和预防营养盐污染以及赤潮暴发的有效手段。

Size-fractionated biomass of phytoplankton and its environmental impact factors had been discussed based on the assessment of the pollution status and nutrient level of water quality in the waters off the northwestern Xiamen Island through the field survey data from September to November 2018.The results indicated that the nutrient level in Tongan Bay was judged to be eutrophication in November,which was medium or heavily polluted,while the nutrient level in the waters of the Jiulong River and the western of Xiamen Island were judged to be slightly phosphorus limited potential eutrophication or phosphorus limited potential eutrophication between September and November,which was heavily polluted.The size-fractionated biomass of phytoplankton in the waters of Tongan Bay and western Xiamen Island was significantly different from that of the Jiulong River,with the former showing nanophytoplankton>microphytoplankton>picophytoplankton,while the latter showed microphytoplankton>nanophytoplankton>picophytoplankton.Correlation analysis showed that microphytoplankton biomass was significantly positively correlated with NO3-N+NO2-N,DIN,DIP,and SiO3-Si,while negatively correlated with salinity.Nanophytoplankton biomass was significantly positively correlated with the euphotic depth(Zeu),NH4-N,and DIP.Picophytoplankton biomass was significantly positively correlated with Zeu,NH4-N,and DIP,while negatively correlated with pH.The results indicated that the most important environmental factors affecting the phytoplankton size community were salinity,Zeuand DIP,especially DIP,whose elevated levels were likely to cause phytoplankton to develop from a phosphorus-stressed state to a red tide hazard.Control of drainage,real-time monitoring,enhancement of early warning capabilities and improvement of the ecological environment were effective means to control and prevent nutrient pollution and red tides.