太湖介形类动物丰度与生物量

2004年9月~2005年8月对太湖介形类动物进行了季节性调查分析，结果表明：太湖中共有15种介形类动物，其年均丰度为1 590 ind/m2，年均生物量为46 495 μg(dwt)/m2，丰度和生物量在9个湖区的分布状态相似，受介形类自身食性及行为方式的影响，高丰度和高生物量主要出现在夏秋两季的太湖东半部分（包括东太湖、东部沿岸带和贡湖）。9个湖区中，除梅梁湖和贡湖外，其它几个湖区中介形类丰度和生物量的周年变化规律较为一致，而太湖中终年出现物种克氏瘤丽星介（〖WTBX〗Physocypria kraepelini〖WTBZ〗）、豆形豆形玻璃介（〖WTBX〗Fabaeformiscandona〖WTBZ〗 cf. 〖WTBX〗fabaeformis）和塔尔薄丽星介（Dolerocypria taalensis〖WTBZ〗）的自身繁殖力是造成梅梁湖和贡湖中介形类丰度和生物量间存在差异的主要原因，但两湖区中介形类丰度和生物量在整个太湖中所占比重有限，所以不影响太湖总体介形类季节变化趋势，四个季节中介形类的丰度和生物量均值总体呈现出秋＞夏＞冬＞春的规律。在15个物种中克氏瘤丽星介和豆形豆形玻璃介的丰度和生物量最高，所以两者为太湖介形类的建群种。介形类丰度、生物量与环境因子间的相关关系分析结果显示，水体中的植被密度、透明度、温度和溶氧量对介形类丰度和生物量分布和变化的影响较其它环境因子大，但因季节不同而有所变化。

ON ABUNDANCE AND BIOMASS OF OSTRACODS IN TAI LAKE

Fifteen ostracod species were collected from Tai Lake during the period from September 2004 to August 2005.Their abundance and biomass showed a similar seasonal pattern:autumn>summer>spring>winter.Among 15 species,the abundance and biomass of 〖WTBX〗Physocypria kraepelini〖WTBZ〗 and 〖WTBX〗Fabaeformiscandona〖WTBZ〗 cf.〖WTBX〗fabaeformis〖WTBZ〗 were the highest and played important roles in composition of ostracods community in Tai Lake.The mean abundance of ostracods was 1 590 ind/m2,and the mean biomass of ostracods was 46 495 μg(dwt)/m2.There was the same horizontal distribution for the abundance and biomass of ostracods in 9 sampling areas,and then the high abundance and biomass appeared in the east of Tai Lake (such as East Tai Lake,Eastern Coastal Belt and Gong Bay) because of the feeding and behavior habits of ostracods.Among the 9 areas,except for Meiliang Bay and Gong Bay,there was similar seasonal pattern for abundance and biomass in Tai Lake.The differences in Meiliang Bay and Gong Bay were mainly because of high reproduce energy of eurythermal species.Results of Pearson correlations analysis showed:water temperature,transparency,plant density and dissolved oxygen (DO) were important environmental factors affecting abundance and biomass of ostracods in the lake,but there were a few differences with seasons.