钦州湾大型底栖动物生态学研究

通过2008年~2009年在钦州湾及附近海域进行的4个航次的大型底栖动物调查，共获大型底栖动物8门62科94种，软体类最多，其次为多毛类，种类季节变化较大。以优势度指数Y>0.02为判别标准，调查区春季优势种为方格皱纹蛤（Periglypta lacerata (Hanley)）、刺足掘沙蟹（Scalopidia spinosipes Stimpsom）和独齿围沙蚕（Perinereis cultrifera Grube），夏季优势种为方格皱纹蛤、刺足掘沙蟹和持真节虫，秋季优势种为曲波皱纹蛤和网纹藤壶，冬季优势种为肋鲳螺和方格皱纹蛤。春、夏季优势种变化不大，秋、冬季优势种变化较大，除方格皱纹蛤外均为季节特有种。海区底栖生物平均总密度和平均总生物量分别为439ind./m2和115.14g/m2。与20世纪80年代钦州湾茅尾海调查结果相比，平均栖息密度有所升高，但是平均生物量却有较大程度的降低。底栖动物群落的丰富度指数（D）、Shannon-Wiener多样性指数（H′）和均匀度指数（J′）平均值分别为4.01、1.80和0.73，水平不高。用SPSS软件将各站大型底栖动物的平均密度、平均生物量、多样性指数等生态特征值与水深等理化因子进行了Pearson相关分析，结果表明春季各特征指数与环境因子相关性不显著；夏季丰度、多样性指数和均匀度指数均与水深呈显著负相关，种类数、丰富度和多样性指数与沉积物pH呈显著负相关；秋季密度与硫化物呈显著正相关；冬季生物量与硫化物和有机质均呈显著正相关。

Ecology study on the benthic animals of QinZhou Bay

Qinzhou Bay, which is the biggest in Guangxi, is one of the most important areas for developing a marine economy as it is species-rich. In recent years, as human impact has become more serious, problems associated with the geological environment have become more complicated, increasing pressure on the local environment. Because an examination of the benthos is one way of monitoring environmental conditions, ecological surveys of the macrobenthos in Qinzhou Bay were undertaken during four cruises during 2008 and 2009. A total of 94 macrobenthic species were identified, including 36 species of mollusk, 22 species of polychaete, 21 species of crustacean, and six species of echinoderm, as well as nine other species. The greatest number of species was found in the inner bay, followed by the open bay, outside the bay, and neck bay, respectively. The Mollusca was the dominant group in the benthos, followed by the Polychaeta, although the dominant species varied with season. In spring, the macrobenthos was dominated by Periglypta lacerata, Scalopidia spinosipes and Perinereis cultrifera. By contrast, P. lacerata, S. spinosipes and Euclymene annandalei were the most abundant species in summer, Periglypta chemnitzi and Balanus reticulatus in autumn, and Umbonium costatum and P. lacerata in winter. The dominant species, therefore, were similar in spring and summer, but changed in autumn and winter. Periglypta lacerata was the only dominant species throughout most of the year. The average total density and average total biomass of macrobenthos were 439 ind./m² and 115.14 g/m², respectively. Compared with data from the last 20 years, the average abundance of individuals has increased, while biomass has decreased. The average abundances and biomasses were greatest in winter, followed by autumn, and least in spring and summer. An examination of the horizontal distribution of species revealed that the average abundances and biomasses varied with no obvious trends. The average abundances and biomasses were different in different areas, being highest in the open bay, followed by the outer bay, entrance to the bay and finally inner bay. The species richness index is 4.01(D), the diversity index 1.80 (H') and the evenness index 0.73 (J'), which are low. The average species richness index has the same trend in different areas: greatest in the inner bay, least at the entrance to the bay, and similar in the open bay and outer bay. The richness, diversity and evenness indices are significantly negatively correlated with water depth. The species richness and evenness indices are significantly negatively correlated with sediment pH in summer, whereas density is positively correlated with sulfide in autumn, and biomass is positively correlated with sulfide and organics in winter. An abundance/biomass comparison curve method was used to determine the levels of disturbance of the macrobenthic communities. In spring, the macrobenthic community was only slightly disturbed, whereas in the other three seasons the macrobenthic communities were moderately disturbed. However, disturbance was greater in autumn and winter when compared with that in summer.