Presentation on global change and eutrophication of coastal waters by Ingrid Venero

2. Introduction
 Global climate change and human activities are
altering the ecological condition of estuarine and
coastal ecosystems by intensifying problems such as
eutrophication

3. Visual representation of eutrophication

4. 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

6. 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

8. 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

9. 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.

10. 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.

11. 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

12. Distribution of bottom – water hypoxia

13. Effects of tropical storms on dissolved oxygen

14. 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

15. Questions