内陆地区南美白对虾淡化养殖池塘浮游植物群落结构特征及其生态影响因子

Community Characteristics and Influencing Factors of Phytoplankton in Desalination Culture Ponds of Pacific White Leg Shrimp Litopenaeus vannamei

在新疆昌吉市森淼渔业专业合作社6 667 m^(2)、水深约1.6 m池塘中,放入经12 d淡化至盐度0.8左右的南美白对虾(Litopenaeus vannamei)苗种,放养密度约为45 ind./m^(3)。放苗当天即采用标准方法开始第一次采样,每周采样1次,共采集12次,调查新疆昌吉地区南美白对虾淡化养殖池塘中浮游植物群落组成变化,借助多变量分析方法揭示浮游植物群落的结构特征、时空变动及其主要生态影响因子。结果显示:本次调查共鉴定浮游植物103种(属),其中绿藻门种类数最多为39种(属),其次为硅藻门29种(属)和蓝藻门23种(属),其他各门种类数不多于4种(属);优势种8种(属)。调查期间浮游植物总平均密度为(2.05±2.93)×10~8ind./L,变幅为4.58×102~9.66×10~8ind./L,总平均生物量为(30.49±33.81)mg/L,变幅为0.80~101.47 mg/L。冗余分析(RDA)表明,铵态氮和活性磷与具星小环藻(Cyclotella stelligera)的相关性较低,而蛋白核小球藻(Chlorella pyrenoidosa)、月牙藻(Selenastrum bibraianum)和衣藻(Chlamydomonas spp.)更易在较高的铵态氮环境中建立优势地位;活性磷含量的增加可能是促进蓝藻大量繁殖的重要因素;植食性浮游动物牧食会对浮游植物群落变动产生一定影响,这种变动更倾向于从小型可食性到较大个体或不可食性种类转变。南美白对虾淡化养殖池塘浮游植物群落结构受生态因子的影响存在显著时空变化,掌握其变动规律对进一步开展池塘水质调控技术提供科学依据。

The structural characteristics,temporal and spatial changes in phytoplankton community composition and their main ecological influencing factors were investigated in a 6 667 m^(2) pond with a water depth of about 1.6 m in Senmiao Fishery Professional Cooperative where desalinated for 12 d to salinity of 0.8 post larval Pacific white leg shrimp Penaeus vannameii were reared at stocking density of about 45 ind./m^(3).The water sample was first collected in the test ponds using the standard method on the day of seedlings once a week,a total of 12 times,by multivariate analysis methods.The results showed that a total of 103 species were identified,with 8 dominant species.Chlorophyta was represented by the most species with 39 species,followed by Bacillariophyta with 29 species,Cyanphyta with 23 species and others less than 4 species.Densities of phytoplankton were found to be varied from 4.58×10^(6)ind./L to 9.66×10^(8)ind./L,with an average of(2.05 ±2.93)×10^(8)ind./L,and biomass from 0.80 mg/L to 101.47 mg/L with an average of(30.49 ±33.81) mg/L.Multivariate analysis indicated that the correlations between Cyclotella and ammonium and between Cyclotella and active phosphate were very insignificant;Chlorella pyrenoidosa,Selenastrum bibraianum and Chlamydomonas spp.became more prone to be dominant taxa in high concentration ammonia water;the increases in content active phosphate became an important incentive for the Cyanophyta bloom;Grazing behavior of herbivorous zooplankton had an effect on phytoplankton community succession,which preferred to transform phytoplankton from small edible species into larger or inedible species.The understanding of temporal and spatial changes in phytoplankton community composition and their main ecological influencing factors in desalinated Pacific white leg shrimp culture ponds helps to provide scientific basis for further researches on manipulating for aquaculture pond of penaeid shrimp.