辽东湾浮游生物粒径结构稳定性分析

Ecological stability of plankton biomass size structure in Liaodong Bay

基于2012～2014年春、夏、秋、冬季辽东湾网采浮游生物及环境因子的调查资料,采用显微测微计法结合粒径谱理论分析了辽东湾南、北2个区域的浮游生物粒径结构特征,并构建了浮游生物群落稳定性评估模型.结果表明,辽东湾海域浮游生物不同营养级间能量传递效率近似相等,但生态转化效率偏低;2012～2014年辽东湾南部区域稳定性系数平均为0.53,北部区域平均为0.47,南部区域浮游生物群落整体上较北部稳定,夏季表现更为明显,说明南部区域受环境胁迫影响较小;海水营养状况分析表明,北部区域属于富营养化水平较高海域,营养指数（E）平均为1.69,南部区域基本属于低营养水平,营养指数（E）平均为0.42,富营养化会导致系统偏离稳定状态;本文构建的浮游生物群落稳定性评估模型可尝试比较不同海域浮游生物群落的健康状况.

Based on net collection and analyzing of plankton samples over all consecutive seasons during 2012～2014, we investigated the characteristics of plankton population size and structure in northern and southern region of Liaodong Bay by microscope micrometer and biomass size spectrum theory. A stability assessment model of the plankton communities was also established. The results showed that energy transfer efficiencies of plankton in different trophic levels were approximately equal, but the conversion efficiency decreased with increasing trophic level. The stability factor of southern Liaodong Bay was 0.53, while it was 0.47 in northern region. Plankton communities in southern area of the Bay were more stable than those of northern areas and it was more apparent in summer season, which indicated that environmental stress was less for southern area. The average of eutropher coefficient（E） was 1.69 in northern area, suggesting that it was at a high eutropher level, while southern area was at a light eutropher level with the average of E 0.42. The seawater nutritional status analysis contributed that eutrophication was a potential cause of the deviation from steady state in these communities. The stability assessment model developed in this study would also be useful for comparing the health of plankton communities in different bays.