Study on impacts of net-cage culture on marine benthos in Xiangshan Bay East China sea

摘要

The seasonal variations of the density of benthic microalgae,the concentration of chlorophyll a,the biomass,individual abundance and dominant species of benthos,TN,TP,OC and sulfides between January 2001 and May 2012 have been investigated in this study.The results showed that the abundance of benthic microalgae was 108-812 cell/g,the benthic biomass was 6.68-25.82 g/m2,the density of benthos was 31-124 ind./m2.The residual feed in net-cage cultural areas caused nitrogen,phosphorus and organics contamination and the community structure was destroyed by the rapid deterioration of sediment environment.Benthos in non-cultural areas and inner bay were more than that in cultural areas and bay mouth respectively.The concentration of TN,TP,OC and sulfides in cultural areas and inner bay was significantly higher than that in non-cultural areas and bay mouth respectively.With the increasing of cultural time,the concentration of TN,TP and sulfides were increased,while the density of benthos and benthic microalgae were decreased at the surface sediments in cultural areas.