唐山祥云湾海洋牧场海域网采浮游植物群集特征研究

为研究唐山祥云湾海洋牧场海域网采浮游植物群集特征, 于2020年11月至2021年11月在祥云湾海洋牧场海域进行了浮游植物及环境因子的周年逐月调查。共鉴定浮游植物41属78种, 其中硅藻33属62种, 甲藻7属15种, 硅鞭藻1属1种, 年均丰度为205.58×10⁴ cells/m³, 多样性指数H''为2.88。与近岸非增殖海域不同, 该海域浮游植物的丰度及群落结构指数在春夏季水生生物繁生期达到全年最低。优势类群的季节演替明显, 其中, 3~5月以诺氏海链藻最占优势, 9~10月以角毛藻和中肋骨条藻最占优势, 周年优势类群以圆筛藻和角毛藻最占优势, 其优势度变动在6月前以圆筛藻显著为高, 之后则以角毛藻显著为高; 此外,甲藻的优势度在泛冬季(11~2月)达到最高。鱼礁区与对照区的对比结果显示, 两区域浮游植物的群落变化均可划分为泛冬季低温期(11~2月)、春夏季繁生期(3~6月)、泛秋季降温期(7~11月)三个时期。链状浮游植物的丰度在礁区明显高于对照区, 而非链状浮游植物则相反; 与生物作用关系密切的溶解有机碳、pH值在礁区低于对照区, 而总磷和溶解态硅则相反。Pearson相关及冗余分析(RDA)显示, 两区域浮游植物与环境因子的显著相关关系在不同时期差异明显。春夏季繁生期牡蛎礁上的贝类滤食活跃, 浮游植物与环境因子的关系最为密切, 浮游植物与环境因子的相关关系达到显著水平的数量最多。礁区与对照区浮游植物的群集特征差异可能受到礁体附着生物活动及潮汐往复流混合作用的影响。

STUDY ON THE ASSEMBLAGE CHARACTERISTICS OF NET-PHYTOPLANKTON IN MARINE RANCHING AREA OF XIANGYUN BAY, TANGSHAN, CHINA

The community characteristics of net-phytoplankton were studied based on the data collected through semi-monthly and monthly sampling surveys between November 2020 and November 2021 in marine ranching area of Xiangyun Bay, Tangshan. A total of 78 species belonging to 41 genera were identified, including 62 species belonging to 33 genera of diatoms, 15 species belonging to 7 genera of dinoflagellates, and 1 species belonging to 1 genus of dictyochophyceae. The abundance and community structure index of phytoplankton in the study area reached the lowest level during the proliferation period of spring and summer, which were different from the coastal non-mariculture area. Seasonal succession of dominant groups was obvious, among which Thalassiosira nordenskioeldii was the most dominant species from March to May, Chaetoceros spp. and Skeletonema costatum were the most dominant groups from September to October. Generally, during the whole study period, Coscinodiscus spp. was the most dominant groups before June, and then Chaetoceros spp. was the most dominant groups from July to November. In addition, dinoflagellates dominance was the highest in the pan-winter low temperature period (November to February). Comparison between the reef and control area showed that the phytoplankton community changes in the two areas could be divided into three periods: pan-winter low temperature period (November to February), spring and summer proliferation period (March to June), and pan-autumn cooling period (July to November). The abundance of chain-forming phytoplankton in reef area was higher than that in the control area, while the non-chain-forming phytoplanktonshowed an opposite pattern during the whole study period. DOC and pH that closely related to biological perturbation in reef area were lower than that in the control area, while TP and DSi exhibited opposite patterns. The Pearson correlation and redundancy analysis (RDA) showed that the correlation between phytoplankton and environmental factors in different periods were significantly different between reef and the control area. In spring and summer proliferation period, the filtration of shellfish on the oyster reef tended to be strong, and phytoplankton and environmental factors appeared strong and significant associations. The variations in phytoplankton assemblage between the reef and the control area could be affected by the activities of reef attached organisms and the mixing of tidal reciprocating currents.