Investigation on the Relationship between Seasonal Climate Variables and Water Quality near Aquaculture Farms

Abstract

              Water is essential requisite for human being, aquatic organisms, and aquaculture production. In aquaculture sector especially for shrimp farming, water is common factor because it is water intensive enterprise and required daily water exchange. Physical, chemical, and biological characteristic can determine to ensure water quality for the species alive. In addition, anthropogenic activities and natural processes such as seasonal and annual variation of climate can cause water quality change. This research studied the relationship between climatic and water quality parameters based on secondary data from 2016-2018 at the canal near aquaculture farms in Bangkok and Samut Prakan province. Rainfall and air temperature used for climatic parameters, and pH, water temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonia (NH₃-N), nitrate (NO₃^--N) and total phosphorus (TP) used for water quality parameters. Pearson’s correlation used as an analysis tool for this study. Results revealed that significantly negative correlation observed between rainfall and pH (r= -0.67) in winter season. Same results were found between air temperature and BOD (r=-0.50), and NH₃-N(r= -0.65), and TP (r= -0.50). In rainy season, water temperature (r= 0.67) and DO (r= 0.56) were significantly positive correlated with air temperature. In summer, positive correlation occurred between air temperature and water temperature (r= 0.60), and rainfall and NO₃^- -N     (r= 0.54). This study suggests that good water quality condition occurred in winter season because less variations of temperature and rainfall. In addition, less BOD, NH₃-N, NO₃^--N and TP values as less effect of surface runoff from the land.