Assessing the impact of nutrient loads on eutrophication in the semi-enclosed Izmir Bay combining observations and coupled hydrodynamic-ecosystem modelling

Intense human activities may strongly affect coastal environments threatening natural, societal and economic resources. In order to propose adequate measures preserve marine areas, a thorough understanding of their physical biogeochemical features is required. This study focuses on one such area, Izmir Bay located in the Eastern Mediterranean Sea. highly populated area subject many induced stressors as pollution eutrophication, that has been suffering high nutrient loads for decades. Despite construction Çiğli waste water treatment plant 2000-2001 reduce pressures continue occur. To current dynamics spatial temporal variability, three-dimensional coupled hydrodynamic-ecosystem model (Delft3D modelling suite’s FLOW ECO modules) implemented. Using model, effect excessive inorganic loading ecosystem main cause this eutrophication explored an effort advise mitigation efforts focusing eliminating eutrophication. Results different scenarios show Inner Middle are nitrogen-limited while Outer phosphorus-limited. regions more sensitive variations nitrogen input due low (<16) N/P ratio nutrients seawater. An increase triggers events with primary production immediate response. Conversely, ratios above 16 phosphate inputs, which causes considerable enhancement algal production. shows vulnerability anthropogenic simulations indicate management plans should consider reducing DIN discharges both inner-middle zones well inputs from Gediz River. Additionally, be reduced avoid overall Bay, larger part Bay.