牡蛎和鱼类网箱养殖对象山港大型底栖生物群落的影响

As one of the main groups of the marine ecosystem, macrobenthos is widely used as indicator organism of environmental quality status. Furthermore, macrobenthos plays an important role in material and energy flow of the marine ecosystem. China has become a major mariculture country around the world, however, the ecological and environmental effects from mariculture are highly concerned by scientists. The impacts of mariculture on the macrobenthos mainly by altering the physical and chemical factors of sediment and the macrobenthic food sources, etc. Currently, there have been a fair number of studies done on the effects of mariculture on macrobenthic communities, but most of them focus on the influence results, such as the abundance, diversity and structure of macrobenthic communities are changing due to the mariculture. However, the effects of mariculture on food sources of the macrobenthos are rarely studied, as well as the mechanism of how the mariculture affecting on the macrobenthic communites. In this project, the Xiangshan Bay is selected as the research area. Based on the historical monitoring data of macrobenthos, physical and chemical parameters of oyster culture area, fish cage culture area and control area in 2015, the community structure and diversity of macrobenthos will be analyzed. And then, the effects of physical and chemical changes of two types mariculture on macrobenthic communities will also be analyzed. Hereafter, combined with the field supplement investigation and in situ experiment, the effects of different types of mariculture on food sources of the macrobenthos will be analyzed using fatty acid and stable carbon and nitrogen isotope analyses, and then the responses of macrobenthos to the changes in food sources caused by mariculture will be revealed. Finally, we will elucidate the response mechanism of macrobenthic communities to different types of mariculture.

大型底栖生物是海洋生态系统的主要类群之一，不仅具有重要的环境指示作用，还积极参与海洋生态系统物质循环和能量流动。我国是海水养殖大国，海水养殖的生态环境问题一直备受科学界关注。海水养殖主要通过改变沉积物理化环境因子和食物来源等方式影响大型底栖生物，目前，有关大型底栖生物群落对海水养殖响应的报道较多，但大多注重响应的结果，如群落丰度、多样性和结构等发生变化，缺乏从食物来源变化和响应机制等角度入手进行研究。本项目针对象山港牡蛎和鱼类网箱养殖两种类型，收集2015年养殖区和对照区大型底栖生物和理化环境参数的调查资料，分析不同养殖类型大型底栖生物群落结构和多样性特征，并进一步分析养殖沉积环境变化对大型底栖生物群落结构的影响。在此基础上，结合现场补充调查和原位实验，运用脂肪酸标志法和稳定同位素技术，分析不同类型海水养殖对大型底栖生物食物来源的影响，最终阐明大型底栖生物群落对不同类型海水养殖的响应机制。

大型底栖生物是海洋生态系统的主要类群之一，不仅具有重要的环境指示作用，还积极参与海洋生态系统物质循环和能量流动。我国是海水养殖大国，海水养殖的生态环境问题一直备受科学界关注。本项目针对象山港牡蛎和鱼类网箱养殖两种类型，分析不同养殖类型大型底栖生物群落结构和多样性特征，及其与养殖环境的关系。在此基础上，结合现场补充调查和原位实验，运用脂肪酸标志法和稳定同位素技术，分析不同类型海水养殖对大型底栖生物食物来源的影响。研究结果表明，象山港牡蛎、网箱养殖区以及对照区共鉴定出96种大型底栖生物，其中多毛类43种，软体动物22种，甲壳类动物16种，棘皮动物6种，其它类动物9种。在牡蛎养殖区，不倒翁虫的丰度最高，其次分别为异蚓虫、豆形胡桃蛤、双眼钩虾；在网箱养殖区，丝鳃虫的丰度最高，其次分别为异蚓虫、侧花海葵、纵肋织纹螺。聚类分析结果表明，网箱养殖区的大型底栖生物群落与其他3个区域的相似度最低。SIMPER分析结果表明，网箱养殖区中更高丰度的丝鳃虫、纵肋织纹螺、侧花海葵和丽核螺是导致底栖生物群落组成与其他区域差别的主要原因。双因素ANOSIM检验结果表明，象山港牡蛎、网箱养殖区以及对照区的大型底栖生物群落组成存在显著的区域差异和季节差异。牡蛎养殖区和网箱养殖区大型底栖生物功能群组成相似，主要由于两种海水养殖均促进了表层沉积物摄食者和肉食者的丰度和生物量增加。当牡蛎养殖停止3年后，大型底栖生物群落的种类数、丰度、Shannon-Winner多样性指数、丰富度指数等均出现了显著升高，而生物量出现了下降。海水养殖对大型底栖生物食物来源的影响存在显著的种类特异性。未来，项目组将尝试在海水养殖区利用更多的大型底栖生物开展实验，筛选出养殖区沉积物修复高效种。本研究成果可以为我国近海海水养殖的生态环境影响评估，以及海水养殖区生态恢复和修复提供科学依据。