夏冬两季舟山砂质潮间带小型底栖生物的分布特征及影响因素

Distribution Pattern of Intertidal Meiofauna in a Sandy Beach of Zhoushan in Summer and Winter and Its Influencing Factors

于2010年7月(夏季)和2011年1月(冬季)对舟山朱家尖东沙砂质潮间带进行调查,分析了东沙砂质潮间带的环境因子和小型底栖生物的组成、丰度和生物量。结果表明,小型底栖生物夏、冬两季平均丰度为(495±250)ind.10cm-2,夏、冬两季平均生物量为(948±443)μg dwt.10cm-2。共鉴定出12个小型底栖生物类群,按丰度,自由生活海洋线虫为最优势类群,占小型底栖生物总丰度的49%,其次为涡虫(29%)和底栖桡足类(12%);按生物量依次是涡虫(54%)、腹毛虫(16%)和线虫(15%)。小型底栖生物的丰度存在潮带差异,高潮带大于中潮带;生物量无潮带差异。小型底栖生物丰度在夏季表层(0～4cm)分布最多(43%),向深层呈现递减趋势;冬季在各层分布较为均匀,次表层(4～8cm)分布最多(29%)。小型底栖生物及主要类群的丰度受环境因子影响显著,总丰度与气温、间隙水温度、盐度和沉积物初级生产水平密切相关。

Dongsha sandy littoral zone of Zhujiajian in Zhoushan was investigated in July （summer） 2010 and January （winter） 2011, and environmental parameters and meiofaunal group composition, abundance, biomass were analyzed. Results showed that the average abundance of the meiofauna was （495± 250） ind ·10cm^-2, and the average biomass was （948±443）μg dwt· 10cm-2. Among the 12 major meiofaunal groups sorted, the free living marine nematodes were the most dominant in term of abundance, accounting for 49% of the total, and the other dominant groups were Turbellaria （29%） and Copepoda （12%）. In term of biomass, the most dominant group was Turbellaria, accounting for 54% of the total, followed by Gastrotricha （16%） and Nematoda （15%）. There was significant difference in the abundance of meiofauna between high and middle tidal zones, but no significant difference in biomass. The top layer （0~4 cm） supported the most abundant meiofauna （43%） in summer and the abundance decreased with depth. In winter, the vertical distribution was relatively uniform, and the subsurface sediment （4~8 cm） supported the most abundant meiofauna （29%）. Statistical analysis showed that the abundance of total meiofauna and dominant groups were positively correlated to air temperature, interstitial water temperature, salinity and sedimentary chlorophyll-a concentration.