渤海湾大型底栖生物群落结构变化及原因探讨

根据近6年来的渤海湾大型底栖生物群落的资料,以及2011年的现场调查数据,从渤海湾底栖生物群落结构的变化特征出发,分析了其变化的过程和规律.同时结合渤海湾水域近几年来的水动力条件以及营养盐、溶解氧等水质特征变化,探讨底栖生物群落变化的原因.结果表明,渤海湾大型底栖生物的物种数、生物量、丰度、丰富度指数、多样性指数的高值区皆集中分布在海河口北侧离岸较远的海域,而低值区则基本集中分布近岸海域,且呈现由近岸向外海逐渐增加的趋势.渤海湾大型底栖生物群落变化可大体分为3个明显的时间节点:第一个时间节点为2005年和2008年,底栖生物群落无论总物种数、生物量和丰度都较高;第二个时间节点为2009年和2010年,底栖生物群落的上述指标值最低,表明这两年渤海湾受自然变化和人为因素干扰的程度加剧;2011年,由于渤海湾水域的各项强有力的环保措施的实施,底栖生物群落的上述指标值最高,说明其得到一定程度的恢复.渤海湾水域底栖生物群落变化受到该区域的物理因素、化学因素和生物因素的共同影响,变化特征也与各环境因素的变化基本吻合.

Study on the Changes of Macrobenthos Communities and Their Causes in Bohai Bay

Based on the analysis of macrobenthos samples collected from Bohai Bay, China in 2011 and the data obtained from the nearly the same sampling area during last six years, as well as the hydrological conditions, nutrients and dissolved oxygen, the characteristics of the changes in macrobenthos communities and their response to environmental variables were derived. Results showed that the distribution of the values of species number, abundance, biomass, richness index and diversity index reflected a gradient from the coastline to the open sea with the higher values concentrated at the open sea in the north part of Haihe estuary. The macrobenthos communities showed an obvious fluctuation over last six years, composed of three nodes. The first time node was in 2005 and 2008, the total species number, abundance and biomass maintained relatively high; the second time node was in 2009 and 2010, the values of the above three indices were the lowest in the three time nodes due to the increasing anthropogenic disturbances and natural changes; the third time node was in 2011, the values of the above three indices were the highest since many effective environmental protection measures had been carried out, indicating that the macrobenthos communities were recovered to a certain degree. The integrated impacts from the physical, chemical and biological variables induced by natural changes and anthropogenic disturbances, such as over-fishing, coastal land reclamation and sewage discharge were the triggers for the changes of macrobenthos communities. Furthermore, the variation characteristics of macrobenthic communities and environmental factors were generally in accordance with each other.