Meiofauna in autumn in Daya Bay of South China Sea

The abundance and biomass of meiofauna in Daya Bay was investigated for the first time based on samplings obtained from 9 stations in October 2009.The average abundance of total meiofauna amounted to(593±265)ind.(10cm) 2,which showed the tendency of increase from littoral sea to open sea.The average biomass and production reached(568.39±294.49) and(5115.53±2811.14)μg.(10cm) 2(dwt),respectively.Among the 17 main meiofaunal groups sorted,free-living Nematoda dominated 92.24%,followed by Polychaeta(2.05%) and Copepoda(1.98%).In terms of biomass,Nematoda and Polychaeta represented absolute predominance and accounted for 38.47% and 29.97%,respectively,followed by Oligochaeta(13.82%) and Ostracoda(9.15%).In vertical distribution of the average abundance in the top 0 10cm sediments,53.02% of the total meiofauna and 51.44% of the nematodes occurred in the top 0 2 cm depth.Statistical analyses showed that the abundance of meiofauna and Polychaeta was negatively correlated to the weight percentage and sediment particle size,and copepods were negatively correlated to sediment particle size only.This study suggests that the abundance ratios of nematodes to copepods(N/C) might be a useful indicator for indicating marine environmental pollution to a large extent.