1. Dead zones, climate change and ocean acidification Fish 323

2. Dead zones Regions of very low oxygen also called hypoxic zones Few forms of marine life can survive In 2008 405 dead zones were identified world-wide Are often ephemeral – they come and go Causes: settlement of plankton to bottom where decay consumes most oxygen

5. Primary causes Agricultural run off Oregon: zones thought to be natural

6. The Black Sea Extensive dead zones in the 1980s Fertilizer use declined dramatically with collapse of Soviet Union By 1996 no dead zone found

7. The Louisiana dead-zone

9. Ecosystem consequences Shifting distributions of mobile animals Killing of less mobile species Level of concern is subject to considerable debate

10. The “good” side of Dead Zones Hypoxic zones have been with us for a long time – are the source of scale records used in paleo-ecological studies Oil, gas and coal resources are the result of anoxia Can be a potential site of carbon sequestration.

11. Climate change

13. Temperature Scenarios

14. Key impacts Warmer (mostly) Change in rainfall wetter some places, drier others Sea level increase Increased variability and storms Increased CO 2 in ocean

15. Projected changes in temperature

16. Rainfall and runoff

17. Sea level rise

20. Tuvalu and Pacific Islands

21. Tuvalu will disappear

22. Impacts on fisheries

23. The debate What can be done –Reduction in CO2 emissions –Carbon sequestration Ocean fertilization –Mediation – atmospheric shielding The role of adaptation –How rapidly can plants and animals adapt –How rapidly can human society adapt

24. Ocean acidification

26. Consequences of acidification coccolithophores, corals, foraminifera, echinoderms, crustaceans and molluscs cannot form calcarious structures Decreased survival and reproduction of other animals

27. Coccolithophore are single-celled algae, protists and phytoplankton belonging to the division haptophytes. They are distinguished by special calcium carbonate plates

28. The projections Corals, etc will disappear leading to dramatic changes in marine food webs But cocolithophores have become more abundant and heavier as oceans have warmed How rapidly can species adapt to changing ocean acidity?

29. Summary re climate change The major long term challenge in aquatic resource management While there is much debate about magnitude of impacts it is safe to assume that things will change There will be winners and losers