海洋真核微藻粒级结构及其环境影响因素

采用高通量测序-分子鉴定分级技术于2018年对大长山岛临近海域微藻粒级结构进行了研究，同时探讨了叶绿素a分级法测算微藻粒级结构的误差.结果发现，叶绿素a分级法测算微微型藻类（< 3μm）误差高达82%，严重低估了小粒径微藻的组成，分子鉴定分级法测算春季小粒径微藻生物量组成平均为86%，夏季平均为52%，秋季平均为20%.春季优势种抑食金球藻生物量占41%，夏季优势种金牛微球藻生物量占21%，这2种微微型藻类会严重影响滤食性贝类正常摄食生长，养殖风险较高.总氮、总磷、溶解硅等环境因子和贝类摄食的下行效应影响着该海域微藻粒级结构的变化.

Size-fractionated eukaryotic microalgae and its influencing factors Dachangshan Island and its adjacent waters

In this study, constitution of microalgal particle size in the adjacent waters of Dachangshan island was investigated in 2018 using the high-throughput sequencing-molecular identification and classification technology, and the estimation error of the classification method based on chlorophyll a was assessed. The result showed that the average estimation error of microalgae with a particle size (< 3μm) assessed using the classification method based on chlorophyll a reached 82%, leading to serious underestimation in the composition of microalgae with small particle size. Base on the molecular identification and classification technology, the average biomass proportion of microalgae with small particle size (< 3μm) was 86% in spring, 52% in summer, and 20% in autumn. Aureococcus anophagefferens with the biomass proportion of 41% was the dominant microalga in spring while Ostreococcus tauri with the biomass proportion of 21% became dominant in summer. Both A. anophagefferens and O. tauri could inhibit the feeding and growth of filter-feeding bivalves, which would pose a potential risk to bivalve farming. Top-down effects of bivalve feeding and environmental factors, such as total nitrogen, total phosphorus, and dissolved silicon, influenced the particle size constitution/characteristic of microalgae in this area.