Red tide development modeling in Persian Gulf and study nutrient effects on algal bloom

Red tide or algal bloom occurs in estuarine, marine, or fresh water due to accumulating algae rapidly in water column and results in water coloration in high concentration and widespread serious effects on public health, fishing, and even tourism industry. Persian Gulf despite rich reserves of oil and gas, military strategic location, rich resources and valuable diverse aquatic habitats like coral reefs has been recently confronted with this phenomenon due to human, industrial and agricultural waste, oil exploration, permanent ships’ traffic and shallow water, geographical and climate conditions and limited water exchange with external environment. Due to recent broad steady development of red tides that have irreparable effects on the ecosystem, economic conditions, and public health of the coastal residents, society’s need for understanding is more pressing than ever. Among the investigation methods, numerical modeling has great importance due to low time and cost. MIKE software is used in this paper, considering physical, chemical and hydrodynamics factors in a zone and biological aspects of this phenomenon and temperature, salinity and nutrient effects on red tide growth. In fact predicting HABs’ occurrence minimizes their damage by quick preparation of mitigation activity and prevents economic losses in aquaculture industry, desalination equipment, and also respiratory and skin irritation problems for swimmers. In this paper, the effects of pollution outflows and hydrodynamic currents of Persian Gulf on red tide development in 2008-2009 period and variation of dissolved oxygen amount to chlorophyll-A was simulated and studied by utilizing MIEK21 and ECOLAB modules. The simulation results showed that the red tide development direction was according to the Persian Gulf mainstream direction. In addition, chlorophyll-A concentration was higher near the sewage outflows and persistent in those areas at all times till nutrients present there. In addition, by increasing chlorophyll-A concentration, the dissolved oxygen concentration increased.