Meiobenthic Animals of the Tidal Flat Near the Yeonggwang Nuclear Power Plant

Abstract

Meiobenthic community structure of tidal flats near the Yeonggwang Nuclear Power Plant have studied during summer (June) and fall (October) 1997. Examination of sediment samples collected along the transects showed that there were 18 different types of meiobenthos in the study area. The most abundant meiobenthic animals belonged to Phylum Nematoda in both seasons and all transects. However, sediment samples collected near discharge areas, transects A and B, showed relatively lower abundance than other general coastal areas. Another abundant meiobenthic organism is benthic Harpacticoids which is very sensitive to any environmental changes. Polycheats and Ostracods were next abundant meiobenthos which also showed the difference between the study area and other general coastal areas. Only transect C maintained similar meiobenthic abundance and diversity to other coastal areas. Horizontal distribution for transects A and B showed higher densities in upper and mid tidal flat zones. On the other hand, transect C which is located furtherest from the discharges showed an increasing trend in abundance from upper to lower areas. For size distribution analyses showed that animals which fit into the meshsize of 0.125 mm were abundant. Vertical distribution of meiobenthic animals within the sediments for both sampling seasons showed the highest individual numbers in the surface sediment layers of 0-1 cm depth and showed a decreasing trend as sediment gets deeper. Each class of meiobenthos had different vertical profiles. When comparing survey transects A and B with other similar tidal flat areas, this sites seems to a very unstable environment of tidal flats near the Yeonggwang Nuclear Power Plant.