The Rekation Between Water Quality Factors And The Quantity Of Bacteria, Distribution Of Vibrio Species In The Cage Culture Area Of Zhanjiang Port

The Monthly change in quantity of the heterotrophic bacteria,Vibrio and the Vibrio community and the nine water quality factors(Water temperature, Salinity, pH, Dissolved oxygen, Chemical oxygen demand, Chlorophyll a, Ammonia nitrogen, Inorganic phosphorus, Nitrite nitrogen) in the surface seawater derived from culture areas (Nanyou, Maxie, Techeng) of Zhanjiang Port were investigated from December 2009 to November 2010. Analyzed the correlation between the water quality factors and the quantity of bacterias, and with bacterial indicators of the quality of the marine environment was assessed. Monitoring the water quality factors and investigated the Vibrio are significant for aquaculture environment and early warning to the outbreaks of fish diseases.The main content and results of the study are as follows:1. The correlation between water quality factors and the quantity of bacteriaThe yearly average were as follow: Water temperature was 24.9℃, Salinity was 26.2‰, pH was 7.87, DO was 6.08mg/L, COD was 1.06mg/L, Chlorophyll a was 7.65μg/L, Ammonia nitrogen was 0.138mg/L, Inorganic phosphorus was 0.079mg/L, Nitrite nitrogen was 0.050mg/L.The yearly average of heterotrophic bacteria in caged culture area and comparison area were 1.88×10~4cfu/mL and 1.16×10~4cfu/mL. The yearly average of vibrio in caged culture area and comparison area were 7.54×10~2cfu/mL and 3.85×10~2cfu/mL.The quantity of heterotrophic bacteria and Vibrio was closely positively correlated with water temperature, COD, chlorophyll a, ammonia nitrogen, nitrite nitrogen(P<0.05), but significantly reversely correlated with the salinity (P<0.05). And they were no significant correlation with pH, DO and inorganic phosphorus.Compared with the same site in different seasons of the quantity of heterotrophic bacteria, the highest seasons were during summer and autumn, the second was in spring, and the lowest was in winter. Comparative Results of Vibrio was little difference with heterotrophic bacteria. Nutrient rich, higher temperature, Serious pollution in summer and autumn having the highest quantity of Vibrio, the second was in spring, and the lowest was in winter.2. The diversity of distribution of VibrioCombined with the BOX-PCR and 16S rDNA methods, 27 species of Vibrios was Identificated from 448 genus of Vibrios. There were six major Vibrio species(Vibrio harveyi, Vibrio alginolaticus, Vibrio parahaemolyticus and Vibrio vulnificus) in Zhanjiang Port. Vibrio harveyi is the most important one, and most other Vibrio species only appear in individual months.