大鹏澳养殖海域表底层水环境及浮游动物群落结构的比较研究

Water environment and zooplankton community structures in surface and bottom layer seawater in mari-culture area in Dapeng Cove coastal water

2007年5月～2008年4月对大鹏澳鱼类养殖区、贝类养殖区、自然海区（对照区）进行了每月一次的调查，分析比较了不同站点表底层水环境因子和浮游动物种类组成、数量变动的季节差异。结果表明：3个站点表层溶解氧年均值分别为5．46、7．26和8．10mg／L，表层高于底层，表底层差异极显著（P〈0．01）；总氮（TN）、总磷（TP）、活性磷酸盐（PO4-P）、活性硅酸盐（SiO3-Si）、总溶解无机氮（TIN）含量均以鱼类养殖区最高，而pH在鱼类养殖区最低。调查期间，共发现浮游动物82种，表底层浮游动物种类组成相似度为85．37％。原生动物和浮游幼虫是最主要的类群，3个站点表层中浮游幼虫和原生动物密度占浮游动物总密度的比例分别为93．63％、91．64％、81．69％，底层水域这一比例分别为92．04％、90．33％、82．83％。表层浮游动物丰度高于底层，表底层丰度差异显著（P〈0．05）。浮游动物体长频度分布显示：体长小于0.2mm的浮游动物在表层频度为0．533，高于底层（0．367）；体长小于0．3mm的浮游动物在养殖区频度为0．785，明显高于自然海区（0．540），养殖区浮游动物小型化明显。

The seasonal changes in water environment culture and zooplankton community between the sea surface layer and the bottom layer in fish farming area,shellfish farming area and control area in Dapeng Cove were studied during May 2007- Apr. 2008. The resuits showed that the difference of DO level between the two layers were significant （p 〈 0.01 ）, the annual average concentrations of DO in the sea surface layer were 5.46,7.26 and 8.10 rag/L, respectively. The highest annual average concentrations of TN, TP, PO4- P,SiO3-Si ,TIN and the lowest value of pH were all recorded in the fish farming area. 82 species of zooplankton were recorded during the survey period. The similarity of the species composition between the sea surface layer and the bottom layer were 85.37%. Protozoans and nauplii are the most dominant component,accounting for 93.63% ,91.64% ,81.69% in the sea surface layer and 92.04%, 90.33 %, 82.83 % in the bottom layer of the total zooplankton abundance, respectively. The difference of the densities of zooplankton between the two layers were significant （p 〈 0.05 ）. The densities of zooplankton were higher in the sea surface layer than in the bottom layer. The size-frequency distributions showed that the frequency of micro-zooplankton （ 〈 0.2 mm） was higher in the sea surface layer （0. 533 ） than in the bottom layer （0. 367 ）, the frequency of micro-zooplankton （ 〈 0.3 mm） was higher in the mariculture area （0. 785） than in the control area （0. 540）. The small-sized zooplankton was dominant in the mariculture area in Dapeng Cove.