南海小型底栖动物生态学的初步研究

SPATIAL DISTRIBUTION OF MEIOFAUNA IN RELATION TO ENVIRONMENTAL FACTORS IN THE SOUTH CHINA SEA

2007年10—11月对南海海域(17—21°N,109—112°E)的小型底栖动物的生态特点进行了研究。结果表明,小型底栖动物的丰度平均为(901±913)ind/10cm2,自近岸向外海域呈递减趋势;平均生物量和生产量分别为(798±713)μgdwt/10cm2和(7185±6421)μgdwt/10cm2。研究海域小型动物的平均丰度与莱州湾和南黄海冬季的研究结果较接近,高于东、黄海,低于胶州湾和长江口。在分选的17个主要类群中,海洋线虫在丰度上占绝对优势(92.9%),多毛类(2.5%)和桡足类(1.5%)所占比例均较小。在生物量上,海洋线虫(41.9%)和多毛类(40.1%)为绝对优势类群,其次是介形类(3.6%)和桡足类(3.2%)。在垂直分布上,占总量约53%的小型底栖动物和52%的海洋线虫分布于0—2cm表层,该结果与长江口较为接近,而较渤海和黄海低。统计分析表明,本海域的小型底栖动物和线虫的数量与沉积物中有机质含量呈显著正相关,与水深呈显著负相关。由海洋线虫与桡足类的数量比(N/C)与本海域环境状况的分析表明,该数值在一定尺度上可为海洋环境监测提供参考。

The spatial distribution of meiofauna in the South China Sea was investigated for the first time based on samplings conducted at 14 stations （from 17°N to 20°N, 109°E to 112°E） from October to December 2007. The average abundance of the total meiofauna amounted to （901±913） ind/10cm^2 in the maximum of （2980±500） ind/10cm^2. The average biomass and production reached （798±713）μg dwt/10cm^2 and （7185±6421） μg dwt/10cm^2, respectively. Among the 17 main meiofaunal groups sorted, free-living Nematoda was the most abundant group accounting for 92.9%, followed by Polychaeta （2.6%）, Copepoda （1.5%）, and Kinorhyncha （0.1%）. In terms of biomass, Nematoda and Polychaeta accounted for 41.9% and 40.1%, respectively, followed by Ostracoda （3.6%） and Copepoda （3.2%）. In vertical distribution of the average abundance in 0--8em sediments, 53% of the total meiofauna and 52% of the nematodes occurred in 0--2cm depth. Similar pattern was found only in the Changjiang （Yangtze） River estuarine and adjacent sea area, where the proportion of the abundance in surface sediments was lower than those in other sea areas of China. Statistical analyses show that the meiofaunal abundance was positively correlated to the content of sediment organic matter, but negatively to the water depth. The meiofaunal abundance in the South China Sea was similar to those in most samplings in the Bohai Sea and the Yellow Sea, but distinctly higher than those in the East China Sea, and conspicuously lower than those in the Jiaozhou Bay and Changjiang （Yangtze） River Estuarine. The abundance ratios of nematodes to copepods （N/C） correspond largely to the pollution status in the sampling area, indicating the values might be a useful indicator to marine environmental pollution on larger scale.