A comparison of eutrophication impacts in two harbours in Hong Kong with different hydrodynamics

Eutrophication impacts may vary spatially and temporally due to different physical processes Using a 22 year time series data set (1986-2007) a comparison was made of eutrophication impacts between the two harbours with very different hydrodynamic conditions Victoria Harbour (Victoria) receives sewage effluent and therefore nutrients are abundant. In the highly-flushed Victoria the highest monthly average Chl a (13 mu g L-1) occurred during the period of strongest stratification in summer as a result of rainfall runoff and the input of the nutrient-rich Pearl River estuarine waters but the high flushing rate restricted nutrient utilization and further accumulation of algal biomass In other seasons vertical mixing induced light limitation and horizontal dilution led to low Chl a (<2 mu g L-1) and no spring bloom Few hypoxic events (DO