不同水深条件下刺参养殖池塘大型底栖动物群落结构季节性变化特征

Seasonal changes in macrobenthic community structures of sea cucumber Apostichopus japonicus(Selenka) farming ponds at different water depths

于2012年7月至2013年4月调查了荣成靖海湾3个不同水深的刺参(Apostichopus japonicus)养殖池塘内大型底栖动物的构成,以了解不同水深对刺参养殖池塘环境条件的影响以及由此引起的大型底栖生物群落结构的改变。结果表明:3个不同水深梯度池塘(1#浅水位、2#正常水位和3#高水位)底部光照强度、叶绿素a(Chla)和总有机物(TOM)含量存在显著差异,各池塘水温差异不显著。光强、Chla和TOM含量在夏季、冬季和春季均表现为1#池塘显著高于3#池塘;秋季各池塘间光强和TOM含量差异不显著,Chla含量则表现为3#池塘显著高于1#池塘。各季节3个池塘间大型底栖动物在种类组成、丰度、生物量和多样性指数上均存在显著性差异。大型底栖动物丰度和生物量夏季均表现为1#池塘显著高于3#池塘,秋季和冬季则相反;春季1#池塘丰度显著高于3#池塘,生物量则差异不显著。这些差异主要与其各自优势种及其优势度指数大小有关。大型底栖动物多样性指数夏季和秋季均表现为1#池塘高于3#池塘,春季则相反,冬季各池塘间多样性指数差异不显著。单因子相似性分析(ANOSIM)表明,各季节3个池塘间大型底栖动物群落结构均存在显著差异,表明水深梯度对刺参养殖池塘大型底栖动物群落结构造成显著性影响。相似性百分比分析(SIMPER)显示,各季节对3个池塘间大型底栖动物群落差异起主要作用的物种为各个池塘的优势种。典范对应分析(CCA)表明,水深、Chla和TOM含量为影响大型底栖动物群落的主要环境因子。

Sediment samples were collected from three sea cucumber （Apostichopus japonicus） farming ponds of varying water depths, i.e., low （1#）, normal （2#）, and high （3#） water level depths, in the mariculture zone of Jinghai Bay from July 2012 to April 2013. Macrobenthic community structures were analyzed to investigate the effects of the changes in water depth. Light intensity, Chlorophyll a （Chla） and total organic matter （TOM） contents differed significantly among the three ponds. Light intensity and TOM content of pond 1# were significantly higher than those of pond 3# in summer, winter, and spring; whereas no significant differences were observed among the three ponds in autumn. Chla content of pond 1# was significantly higher than that of pond 3# in summer, winter, and spring; but significantly lower than that of pond 3# in autumn. No significant differences in water temperature were observed among the three ponds for any of the four seasons. Throughout the investigation, 41 macrobenthic species were identified, of which 21 species were annelids （51.2%）, 16 species were mollusks （39.0%） and four species were crustaceans （9.8%）. Significant differences in species composition, dominant species, abundance, biomass, and diversity index were observed among the three ponds during each season. Macrobenthic abundance and biomass of pond 1# were significantly higher than those of pond 3# in summer, but significantly lower than those of pond 3# in autumn and winter. In spring, macrobenthic abundance of pond 1# was significantly higher than that of pond 3#, with no significant difference in biomass between the two ponds. These results could be attributed to the remarkable fluctuations in the abundance of the dominant species such as Musculus senhousia, Lumbriconeris heteropoda,Cirriformia tentaculata,Ruditapes philippinarum and Eocylichna braunsi. The Margalef＇s richness index of pond 1# was significantly higher than that of pond 3# in summer; and the Shannon-Wiener diversity and Pielou＇s evenness indices of pond 1# were significantly higher than those of pond 3# in autumn. The Margalef＇s richness index and Pielou＇s evenness index of pond 3# however, were significantly higher than those of pond 1# in spring. No significant differences in diversity index were observed among the three ponds in winter. Hierarchical cluster analysis based on the Bray-Curtis similarity coefficients revealed that the community structure similarities among the three ponds were 43% in July, 37% in October, 43% in January and 48% in April. The low similarities among the three ponds suggested that the macrobenthic community structures were significantly influenced by differences in water depth. The analysis of similarities （ANOSIM） indicated significant differences in species compositions among the three ponds for each season. The similarity percentages analysis （SIMPER） showed that the species that comprised the macrobenthic communities of different ponds, were also the dominant species in each pond for each season. Canonical correspondence ordination analysis （CCA） showed that water depth, Chla, and TOM contents were the key factors influencing the macrobenthic community structures in summer and winter; whereas water depth, light intensity, Chla, and TOM contents were the key factors affecting macrobenthic community structures in spring and autumn.