九龙江口潮下带春季小型底栖动物分布及优势类群海洋线虫的群落结构分析

Meiofaunal distribution and assemblages of the dominant group marine nematode in subtidal zone of the Jiulong River estuary in spring

小型底栖动物世代周期短,对环境的变化较为敏感,是海洋环境质量评估中重要的指示生物,其多样性指数和群落分布格局可以作为环境监测的有效工具.为了解福建省九龙江口小型底栖动物分布及多样性,于2018年4月(春季)在九龙江口潮下带沿着盐度梯度设置11个站位,进行小型底栖动物类群、密度以及自由生活海洋线虫(简称海洋线虫)多样性及群落结构分析,结果共鉴定出9个小型底栖动物类群,分别是海洋线虫、桡足类、多毛类、寡毛类、动吻类、端足类、介形类、双壳类、纽虫,以及其他类.小型底栖动物和海洋线虫的平均密度分别为(323±404)ind/(10 cm^(2))和(292±414)ind/(10 cm^(2)).此外共鉴定出海洋线虫58属,主要优势属有Daptonema、Desmodora、Sabatieria、Parodontophora、Spilophorella和Neochromadora.海洋线虫主要摄食类型为非选择性沉积食性者和刮食者.地理位置接近的站位,海洋线虫群落结构也较相似,部分站位平行样间呈现较高的群落结构空间异质性.根据海洋线虫的各项生物变量进行九龙江口生态质量状况评价,结果表明近河口和远河口的环境受到污染或扰动较大.盐度低的站位其生物多样性指数也低,盐度可能是影响海洋线虫群落结构的重要环境因子.

Meiofauna have a short generation cycle and high sensitivity to environmental changes and have therefore become an important indicator for the assessment of marine environmental quality.The diversity index and community distribution pattern of meiofauna can also be used as effective tools for environmental monitoring.To understand the distribution and diversity of meiofauna in the Jiulong River estuary of Fujian Province,11 stations were set up in subtidal zone of the Jiulong River estuary along a salinity gradient in April 2018(spring)to analyze the group and density of meiofauna,free-living marine nematode(marine nematode for short)diversity and assemblages.The results showed that a total of 9 groups of meiofauna were identified,including marine nematodes,Copepoda,Polychaeta,Oligochaeta,Kinorhyncha,Amphipoda,Ostracoda,Bivalvia,Nemertea,and others.The mean densities of meiofauna and marine nematodes were(323±404)ind/(10 cm^(2))and(292±414)ind/(10 cm^(2)),respectively.In addition,a total of 58 genera of marine nematodes were identified.The main dominant genera were Daptonema,Desmodora,Sabatieria,Parodontophora,Spilophorella and Neochromadora.The main feeding types of marine nematodes were non-selective deposit feeders and epigrowth feeders.The marine nematode assemblages were similar at neighboring stations,and replicate samples of some stations showed high spatial heterogeneity of marine nematode assemblages.In addition,based on the evaluation of ecological quality status in the Jiulong River estuary using the biological variables of marine nematodes,the results showed that nearshore and offshore area suffered heavy pollution or disturbance.The stations with low salinity had a low biodiversity index of nematodes,suggesting that salinity could be an important environmental factor affecting the marine nematode assemblages.