This paper focuses on meiofauna distribution following salinity gradient in the Ham Luong estuary. The aims of this study are: to examine the meiofauna community along estuarine gradient; to investigate the relationship between salinity and meiofauna community. | TẠP CHÍ SINH HỌC 2013, 35(4): 417-423 THE DISTRIBUTION OF MEIOFAUNA COMMUNITY RELATED TO SALINITY GRADIENT IN THE HAM LUONG ESTUARY, MEKONG RIVER Nguyen Van Sinh1*, Nguyen Thi Kim Phuong1, Ngo Xuan Quang2 1 Can Tho University, *nvsinh@ 2 Institute of Tropical Biology, VAST ABSTRACT: Seventeen taxa of meiofauna community in the Ham Luong estuary were investigated and comprised. Free-living nematodes were the most dominant and diverse group, presenting about 77% in the total of meiofauna density. Meiofauna density varied from ± inds/10 cm² to ± inds/10 cm². The meiofauna density shows a decreasing trend from inland station to the brackish water station and it is increasing at mouth station. Significant differences in meiofauna density, diversity and Hill’s indices were found between stations. The ANOSIM showed significant differences between stations in meiofauna composition (overall R = , p = ). The SIMPER analysis clarifies that the average similarity within stations was quite high, changing from EHL3 () to EHL1 (). Keywords: Estuary, meiofauna community, salinity, Ham Luong, Mekong Delta. INTRODUCTION An estuary is characterized by differently marked horizontal and vertical salinity gradients [1]. In different estuaries, the dilution pattern depends on the volume of freshwater, tidal amplitude range and the extent of water evaporation within the estuary [13]. The Mekong river system has special characteristics, through vast high land, mountain and forest, so its habitat shows a higher diversity of bio-resources along the southern coastal area from the vertebrates as fishes to invertebrates, such as mollusc, crustacean and annelids [26]. In Vietnam, meiofauna studies has been researched by Nguyen Vu Thanh & Nguyen Dinh Tu (2003) [18]; Nguyen Vu Thanh (2005) [15, 16]; Nguyen Vu Thanh & Doan Canh (2005) [17]; Nguyen Dinh Tu (2009) [14]. In the South Vietnam, there were some remarkable publications about .
