象山港电厂温排水影响夏季河口桡足类群落结构的通径分析

2016年7~8月对象山港两电厂附近海滩12个站位（G1~G5国华电厂，W1~W7为乌沙山电厂）进行河口桡足类群落结构与多样性的调查。共发现11种桡足类（剑水蚤3种，哲水蚤和猛水蚤各4种）。两电厂附近水体共有的优势种有矮小拟镖剑水蚤（Paracyclopina nana）和短角长腹剑水蚤（Oithona brevicornis），以及乌沙山电厂附近海滩的披针纺缍水蚤（Acartia southwelli）和火腿许水蚤（Schmackeria poplesia）。夏季河口桡足类群落平均密度19.24 ind./L，其中桡足类无节幼体占64.35%，多样性指数（H'）1.16。经多元逐步回归和通径分析表明，温排水成为桡足类种类数（S）和H'波动的决策因子，溶解氧构成S和H'变动的限制因子。温排水对桡足类无节幼体密度有直接的正向作用，通过溶解氧、浮游植物生物量（PB）又对无节幼体产生间接的负向作用，是无节幼体密度波动的限制因子。PB是桡足类群落密度和生物量变动的决策因子。

Path analysis of thermal discharge near power plant on estuarine copepods community structure in Xiangshan bay in summer

In order to understand the path of influence on estuarine copepods community structure and diversity in Xiangshan bay in summer, 24 samples were conducted near the beach of two power plants at twelve sampling stations (G1~G5 near Guohua power plant, and W1~W7 near Wusha Mountain power plant) in July~August, 2016.A total of 11 species of Copepoda (3 Cyclopoida, 4 Calanoida and 4 Harpacticoida) were found.There were two common dominant species Paracyclopina nana and Oithona brevicornis near the seawater of two power plants, as well as Acartia southwelli and Schmackeria poplesia only near the Wusha Mountain power plant.The average density of estuaries copepods community was 19.24 ind./L, wherein copepod nauplii accounted for 64.35%, Shannon-Wiener diversity index (H') was 1.16.Multiple stepwise regression and path analysis showed, thermal discharge conducted the decision factor on the development of estuarine copepods species (S) and H' in summer, and dissolved oxygen(DO) became the limiting factor in variations in S and H'.Thermal discharge had a direct positive effect on density of copepod nauplii, and primarily through DO, phytoplankton biomass(PB) could produce indirectly negative effect on nauplii again, was a limiting factor in nauplii density fluctuations.PB was a decision factor on the development of estuarine copepods community density and biomass.