We evaluated the biodiversity and community structure of the macrobenthos in Sandu Bay, China. In addition, we evaluated the response of the macrobenthos to mariculture practices. This bay is typical of many areas of China's coastline, and is characterized by high density mariculture. We collected samples from 20 sites during nine cruises between May 2009 and February 2010. The Shannon-Wiener index of the macrobenthos in Sandu Bay ranged from 1.45 to 3.22 (mean: 2.40). The Margalef richness index varied from 0.99 to 2.41 (mean: 1.68). The Pielou evenness index changed within the variation from 0.76 to 0.93 (mean: 0.88). The Shannon-Wiener index and Margalef richness index were generally much higher at control sites or sites near the mouth of the bay. A total of five macrobenthic groups were identified at an arbitrary similarity level of 30%, based on samples collected in August in Sandu Bay. The community structure was similar at neighboring sites or at sites with similar mariculture operations. ABC curve analysis suggested that the macrofaunal communities were disturbed in May and August, but not in February and November. Of the environmental variables we measured, dissolved oxygen levels at the surface and sea-bed, acid volatile sulfide content, and sediment oxidizing redox potential were most closely related to the structure of the macrobenthic assemblage (P<0.01).%三都澳是中国沿海典型海水养殖海湾.本研究依据2009年5月至2010年2月共9个航次采样结果,分析该海域大型底栖动物群落结构特点及其对养殖活动的响应.结果显示,三都澳大型底栖动物Shannon-Wiener多样性指数均值为2.40,变化范围为1.45～3.22; Margalef物种丰富度指数均值为1.68,变化范围为0.99～2.41; Pielou物种均匀度指数均值为0.88,变化范围为0.76～0.94.多样性指数和丰富度指数空间分布规律明显,湾口区站位、海带养殖区和对照站位数值较高,网箱养殖站点数值较低.均匀度指数未有明显空间分布差异.多样性指数、丰富度指数和均匀度指数都未见明显时间分布规律.在养殖高峰季节,以30％的相似性程度划分,三都澳水域大型底栖动物可被划分为5个群落.站位间相似性指数总体较低,但位置较为接近的或养殖方式相同的站位间群落结构较为相似.ABC曲线分析显示,2月和11月大型底栖动物生物量曲线位于丰度曲线之上,表明群落结构未受到显著干扰；5月和8月生物量曲线与丰度曲线相互交叉或非常接近,说明此期间群落结构受到一定干扰.相关性分析表明,水体溶解氧、沉积物硫化物含量以及氧化还原电位这3个环境因子与三都澳水域大型底栖动物群落结构相关性较强(P＜0.01).
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