Abstract: To understand the community structure of phytoplankton and its influencing factors in seawater multilevel comprehensive utilization ponds of Yellow River delta, the water environment and phytoplankton status were investigated in May, August and October respectively. The results indicated that 3 phylum and 23 phytoplankton genera were identified, of which 21 genera belonged to Bacillariophyta. Melosira sulcata was the only dominant species in all seasons, and no more than 2 species were 94.29% dominant in water. The richness of phytoplankton was 1.94×105 cells/L with the order of LC>ZY>YZ>JS>TX at different stages of seawater utilization, but there was no significant difference among them (P>0.05). Shannon-Wiener diversity index H’, evenness index J’ and Margalef richness index R were 0.50, 0.33 and 0.52 respectively. At different stages of utilization, for H’ and J, JS > ZY > YZ > LC > TX, and for R, JS > ZY > YZ > TX > LC. The salinity of water increased significantly with the gradual utilization of seawater with the order of JS<YZ<LC<TX<ZY (P<0.05), and pH and dissolved oxygen varied in a contrary trend. The species number of phytoplankton was positively related with pH, dissolved oxygen, richness, water temperature and Shannon-Wiener index (P<0.05) and negatively with salinity (P<0.05). Overall, the biodiversity and evenness of phytoplankton in seawater multilevel comprehensive utilization ponds were lower, and the population was relatively single and influenced by water salinity, water temperature and human disturbance. The results had important significance for improving engineering allocation of different industries (especially aquaculture engineering technology in coastal beach) and production and utilization technology of seawater at different stages of utilization.

Key words: Yellow River delta, seawater multilevel comprehensive utilization, phytoplankton, community structure

摘要： 为了解黄河三角洲海水梯度产业利用过程中浮游植物群落结构及其影响因子，于5月份、8月份和11月份对水环境和浮游植物状况进行了3次调查。结果表明：调查共获得浮游植物3门23种属，其中硅藻21种属占据绝对优势；硅藻门具槽直链藻（Melosira sulcata）在不同季节均为唯一优势种，且94.29%的水体优势种数未超过2种；浮游植物丰度为1.94×105 cells/L；在海水不同利用阶段，LC>ZY>YZ>JS>TX，但差异均不显著（P>0.05）；Shannon-Wiener多样性指数H’、均匀度指数J’和Margalef丰富度指数R分别为0.50、0.33和0.52，在不同利用阶段，H’和J为JS>ZY>YZ>LC>TX，而R为JS>ZY>YZ>TX>LC；水体盐度在不同利用阶段，JS<YZ<LC<TX<ZY，并随海水的逐级利用显著升高（P<0.05），pH和溶氧变化趋势则与之相反；浮游植物的物种数与pH、溶氧及丰度与水温以及Shannon-Wiener指数与溶氧显著正相关（P<0.05），物种数与盐度显著负相关（P<0.05）。总体而言，梯度利用海水中浮游植物生物多样性和均匀度较低，种群较为单一，并受到水体盐度、水温等因素及人为干扰的影响。研究结果对完善不同产业的工程配置技术（特别是沿海滩涂水产养殖工程技术）及海水不同利用阶段的生产利用技术均具有重要意义。

关键词: 黄河三角洲, 海水梯度利用, 浮游植物, 群落结构