Water Quality Of Pearl's West Estuary And Rapid Forecast Determination Of Red Tide

Based on collecting Water quality data in Pearl Estuary since 1988, we investigated red tide (harmful algal Blooms) in Pearl West Estuary from 2000.5 to 2002.2 .We focused on three aspects :(l)The relationship between variation of Nitrogen nutrients and occurrences of red tide in ecosystem; (2)The relationship between water hyacinth biological pollution and occurrences of red tide; (3)The relationship between occurrences of red tide and the concentration of Chlorophyll,COD, Suspect Solid respectivelyin water body . The results Showed that: (1) Due to strong influences of freshwater in Pearl river flow from land source' pollutant, Phosphate nutrient may not be the limiting factor of phytoplankton growth, Hence, the spatial and temporal variation of N nutrients may be characterized the process of phytoplankton growth.(2) The organic pollution due to degradation of water hyacinth, which comes from inner land river, can promote the occurrence of red tide periodically. (3) It is suggested that the concentration of Chlorophyll.a in water bodies can be selected as direct index for monitoring red tide, while Suspect Solid and COD as indirect index for the same purpose. These index proved to be rapidly, effective and feasible, may be satisfied to real demands of local gated fishery by ownselves'rapid monitor and forecast the occurrence of red tide. We suggested that Chlorophyll's physical condition index OD664/OD665 ratio 1.40-1.60 , Concentration of COD 2.5-3.0 mg / L as critical level for the occurrence of red tide ;Before red tide blooming , the concentration of Ammonia in water body will be condensed physically in one region under seasonal wind's effect,We suggested that the concentration of Ammonia is the best indicator for evolution of red tide...