Assessing benthic ecological status in stressed Liaodong Bay (China) with AMBI and M-AMBI

Rapid economic development in recent decades has resulted in environmental degradation of Liaodong Bay, North China, where eutrophication is becoming more evident because of excess nutrients inputs. To assess the benthic ecological status in Liaodong Bay, AZTI’s Marine Biotic Index (AMBI) and multivariate-AMBI (M-AMBI) were applied using both benthic macroinvertebrate density and biomass data collected from Liaodong Bay in July 2007. This first application of AMBI and M-AMBI in Liaodong Bay showed that the nearshore areas of the bay, especially near river estuaries, were severely disturbed, with a clear gradient of disturbance decreasing seaward. Ecological status assessed from density and biomass data was quite similar. Significant relationships were also found between both indices and environmental variables in Liaodong Bay. Moreover, the spatial distributions of both AMBI and M-AMBI matched those of plotted eutrophication indices (EI) in the surface water layer, and significant linear correlations were found between both benthic indices and EI. In general, both AMBI and M-AMBI worked well on assessing the ecological status of Liaodong Bay under eutrophication stress due to excess nutrients inputs.