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

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.