Global climate change impacts Changes in the climate system will cause detrimental effects on: a) ecosystem structure and function b) trophic interactions c) habitat ranges d) migration patterns
Global climate change impacts Effects on temperature and salinity would increase water stratification a) Higher surface water temperatures tend to strengthen pycnoclines – less vertical water circulation b) Increase in freshwater runoff would help increase concentration of nutrients in the surface and decrease surface water salinity
Global climate change impacts Regional wind patterns – will cause changes in circulation and mixing Tropical storms and hurricanes – increased vulnerability of coastal habitats and potential effects on stratification Enhanced hydrological cycle – more water, sediments and nutrients reaching the coastal zone which are likely to enhance eutrophication
Global climate change impacts Sea level rise – Coastal wetlands are further affected by increasing erosion, flooding and saltwater intrusion and may reduce the services they provide as ecosystems.
Eutrophication and human activities Related to excessive loading of nutrients – stimulates phytoplankton growth Anthropogenic activities (industrialization and mechanized farming) produce huge quantities of reactive nitrogen and phosphorus which promote eutrophication processes.
Case history Mississippi River watershed and Gulf of Mexico a) Examples of continental – scale ecosystems that have suffered from landscape changes and are constantly exposed to increasing nutrient loads
Effects of tropical storms on dissolved oxygen
Summary Coastal water quality is declining due to human activities (global climate, hydrological cycles, landscapes and the flux of nutrients such as nitrogen and phosphorus) These excess nutrients are finding their way to coastal zones in increasing amounts and are predicted to increase the incidence and severity of eutrophication and hypoxic water formation. There has to be a reduction of nutrient loads to prevent further degradation