凡纳滨对虾养殖池塘及外河道的浮游植物群落结构变化

Changes of phytoplankton community structure in Litopenaeus vannamei culture ponds and outer river

为了解凡纳滨对虾养殖池塘浮游植物群落结构的动态变化及其与周边水体的差异、浮游植物群落结构与环境因子之间的关联,实验对上海市奉贤区某凡纳滨对虾养殖场的养殖池塘和外河道进行了采样检测,采用多元分析方法对养殖池塘及外河道的浮游植物和环境因子之间的相关性进行了研究。结果显示,池塘在整个养殖周期内共检测出了7门67属(绿藻门属数占51%),其中优势属有5门28属,硅藻门中的小环藻属为最常见优势属(F=1.0);总平均密度为1.09×10~7个/L,其中绿藻门、蓝藻门和硅藻门的平均密度占47%、30%和11%;相关性分析表明,养殖池塘浮游植物群落结构与总氮(TN)、总磷(TP)、高锰酸盐指数(COD)呈极显著正相关。外河道在整个采样周期内共检出7门56属(绿藻门属占46%),其中优势属有6门26属,隐藻属和小环藻属为主要优势属;总平均密度为1.18×10~5个/L,其中隐藻门、硅藻门和绿藻门的平均密度占46%、27%和13%;外河道的浮游植物结构主要受菌落总数和轮虫的影响。相较于外河道,池塘的浮游植物密度大且属类多,并在9—10月大量暴发微囊藻属,对对虾养殖造成了威胁,因此应密切关注总氮、总磷和有机物含量的变化。研究表明,人工干预下的对虾养殖系统与自然生态系统浮游植物群落存在结构差异。本研究结果可为对虾的绿色生态养殖提供参考。

This study aimed to elucidate the dynamics of phytoplankton community structure in Litopenaeus van-namei culture ponds,compare them with those in surrounding waters,and explore the correlation between phyto-plankton and environmental factors.Samples were collected from the aquaculture ponds and the adjacent river of a L.vannamei farm in Fengxian District,Shanghai.Multivariate analysis was employed to examine the relationships between phytoplankton and environmental parameters.The study identified 67 genera across 7 phyla in the ponds,with Chlorophyta predominating at 51%.The dominant genera included 28 genera from 5 phyla,with Chlorella being the most prevalent in Bacillariophyta(F=1.0).The overall average phytoplankton density was 1.09×107 ind/L,with Chlorophyta,Cyanophyta and Bacillariophyta contributing 47%,30%and 11%,respect-ively.Positive correlation were observed between the phytoplankton community structure and levels of total nitro-gen(TN),total phosphorus(TP)and chemical oxygen demand(COD).In the adjacent river,7 phyla and 56 gen-era were detected with Chlorophyta account for 46%,among which 6 phyla and 26 genera were dominant with Cryptococcus and Cryptomonas being the dominant genera.The average phytoplankton density was 1.18×105 ind/L,with Cryptophyta,Bacillariophyta and Chlorophyta comprising 46%,27%and 13%,respectively.The river's phytoplankton structure was primarily influenced by the abundance of colonies and rotifers.The pond's phytoplankton density was significantly higher and more complex than that of the river,with Microcystis blooms posing a risk to the healthy of L.vannamei during September and October.This necessitates close monitoring of TN,TP,and organic matter levels.The study thus highlights the differences in phytoplankton community struc-ture between shrimp culture system under artificial intervention and natural ecosystem.