套尔河贝类增养殖区放流活动前后浮游植物群落结构变化

为了研究贝类增养殖区浮游植物群落结构变化及其影响因素,于2018年5月(增殖放流前)、8月(增殖放流后),对套尔河贝类增养殖区叶绿素a含量、浮游植物群落结构和环境因子的空间分布特征进行了综合调查。在调查海域,5月叶绿素a整体呈现近岸泥滩—离岸逐渐递减的趋势,浮游植物以硅藻为主,优势种是布氏双尾藻(Ditylum brightwellii)、威利圆筛藻(Coscinodiscus wailesii)、羽纹藻(Pinnularia sp.)和夜光藻(Noctiluca scientillans),;8月叶绿素a的分布趋势与5月有明显的不同,高值区出现在离岸,硅藻依然是最重要的浮游植物类群,优势种演替明显,中肋骨条藻(Skeletonema costatum)、菱形海线藻(Thalassionema nitzschioides)、旋链角毛藻(Chaetoceros curvisetus)、派格棍形藻(Bacillaria paxillifera)、丹麦细柱藻(Leptocylindrus danicus)、海洋斜纹藻(Pleurosigma pelagicum)、伏氏海线藻(Thalassionema frauenfeldii)、柔弱角毛藻(Chaetoceros debilis)和尖刺伪菱形藻(Pseudonitzschia pungens)是优势种群。叶绿素a浓度与环境因子的相关分析表明,5月盐度与氨氮是影响叶绿素a浓度的重要因素,8月环境因子与叶绿素a的相关性不显著。浮游植物优势种与环境因子冗余分析(RDA)分析表明,氮、磷营养盐是影响调查海域浮游植物群落结构的主要环境因子。浮游植物群落结构季节性演替明显,贝类增养殖对环境因子和浮游植物群落结构耦合关系还需要进一步研究。

Changes of phytoplankton community structure in shellfish farming area of the Taoer River Estuary before and after the release

The spatial distribution of chlorophyll a(Chl a),phytoplankton community and environmental factors in the Taoer River Estuary were monitored in an ecological survey in May and August 2018,with the purpose of understanding spatial distribution of phytoplankton community structure and abundance in relation to environmental factors in shellfish farming area.In the study area,the Chl a displayed a decreasing trend from nearshore to offshore in May.The major contributor was diatom,and the dominant species were Ditylum brightwellii,Coscinodiscus wailesii,Pinnularia sp.and Noctiluca scientillans.The spatial distribution of Chl a in August was obviously different from that in May,and the high value area distributed inshore.Diatom was still the main phytoplankton,but dominant species changed to Skeletonema costatum,Thalassionema nitzschioides,Chaetoceros curvisetus,Bacillaria paxillifera,Leptocylindrus danicus,Pleurosigma pelagicum,Thalassionema frauenfeldii,Chaetoceros debilis and Pseudonitzschia pungens.The Pearson correlation analysis indicated that salinity and ammonia were the main factors affecting the spatial distribution of Chl a in May,but there was no significant correlation between environmental factors and Chl a in August.The redundancy analysis(RDA)of the dominant species and environmental factors explored that nitrogen and phosphate were the major environmental factors affecting phytoplankton community structure.The seasonal succession of phytoplankton community structure was obvious,and the relationship between shellfish enhancement,environmental factors and phytoplankton community structure needs to be further studied.