2. Climate change and marine ecosystems Sea level  –Destruction of coastal habitats Temperature  –Range shifts –Coral bleaching –Melting sea ice pCO 2  pH  –Acidification Oxygen  –Dead zones

3. Sea level  –Destruction of coastal habitats Temperature  –Range shifts –Coral bleaching –Melting sea ice pCO 2  pH  –Acidification Oxygen  –Dead zones Climate change and marine ecosystems Today Dec. 1

4. All of these changes result from rising [CO 2 ], mainly through its effects on temperature

5. Recall the severe 1997-98 El Niño Maximum temperature anomalies ~3 °C

6. IPCC Report 2007 2011-2030 2046-2065 2080-2099

7. New report: same principle, different scenarios, more extreme predictions IPCC AR5 2013

8. IPCC Report 2007

9. Sea Level Rise Cazenave and Llovel, 2010, Annu. Rev. Mar. Sci. 2010. 2:145–173 Do you remember the main causes of sea-level rise?

10. Figure 10.32. Local sea level change (m) due to ocean density and circulation change relative to the global average (i.e., positive values indicate greater local sea level change than global) during the 21st century, calculated as the difference between averages for 2080 to 2099 and 1980 to 1999, as an ensemble mean over 16 AOGCMs forced with the SRES A1B scenario. Stippling denotes regions where the magnitude of the multi-model ensemble mean divided by the multi-model standard deviation exceeds 1.0.

11. Coastal ecosystems affected by sea level rise Mangroves Salt marshes Important habitat for fish and invertebrates Very productive, fix lots of organic carbon

12. Tidal marsh response to sea level rise of 40 cm Moorhead and Brinson 1995 Mean sea level Vegetation Upland migration of intertidal zones compresses marsh habitat but can increase area of tidal flat habitat

13. Coastal ecosystems threatened by both sea level rise and coastal development Bird et al. 1995 MSL 1 = old sea levelMSL 2 = new sea level

14. Sea level rise likely to reduce diversity & distribution of mangroves and seagrass habitats Indonesia and Indian Ocean have greatest diversity + large projected rise in sea level

15. Many species must move to survive ocean warming

16. Species ranges are temperature-dependent Cheung et al. 2009 “relative abundance” = Fraction of maximum abundance Yellow croaker

17. Estimated 2050 distribution of N=1066 species using projected temperature map Cheung et al. 2009 N invasion = # Invasions by 2050 # species in 2001-2005 N extinction = # Extinctions by 2050 # species in 2001-2005 (Note smaller scale for extinction)

18. Predicted distribution of biodiversity impact due to warming-induced range shifts Turnover = | N invasion -N extinction | N=1066 species Cheung et al. 2009

19. Net effect on fisheries catch potential IPCC2013 Fig. 6-14. Expected change in catch biomass at mid-century relative to past decade under business-as usual scenarios. Range shifts and extinctions combine with decrease in body size (due to fishing, warming, oxygen depletion, and changes in primary production) to drastically reduce predicted catch biomass in some areas.

20. Most reef-building corals live in shallow water between 30° N and 30° S

21. Healthy corals have Zooxanthellae -Symbiotic unicellular algae -Photosynthetic -Algal pigments provide coral color -Provide up to 90% of coral’s energy High temperature causes coral to expel their zooxanthellae -Coral turn white: “Bleaching” -Coral lose their main energy source -If severe, results in death Temperature and Coral Bleaching

23. Bleaching occurs above a threshold temperature 1-2 o C above the long-term summer max temperature Bleaching threshold varies among species and systems Hoegh-Guldberg (1999)

24. http://coralreefwatch.noaa.gov/satellite/index.html Summer of 2010 was one of the worst on record for bleaching in Northern latitudes, Caribbean Stress Level Potential Bleaching Intensity No StressNo Bleaching Watch WarningPossible Bleaching Alert Level 1Bleaching Likely Alert Level 2Mortality Likely

25. Stress Level Potential Bleaching Intensity No StressNo Bleaching Watch WarningPossible Bleaching Alert Level 1Bleaching Likely Alert Level 2Mortality Likely Summer of 2014 was milder in Caribbean but worse in some Northern latitudes and CA Current

26. Hoegh-Guldberg (1999) “Business as usual” model projections of SST: Likely wide-spread die-off of coral reefs by the end of the century Central Pacific Southeast Asia Caribbean

27. Melting sea ice - more extreme at North pole than at South pole -More warming projected in Arctic than in Antarctic -Arctic covered in ice cap, Antarctic covered in land mass

28. Sea-ice effects: different in Arctic and Antarctic http://nsidc.org/sotc/sea_ice.html Arctic Antarctic

29. Sea ice projections (IPCC AR4 Fig 10.14) 1980-2000 Winter Summer 2080-2100 Winter Summer Sea ice concentration (% of time)

30. Arctic polar ice cap melting in summer Sea ice extent = total area in which the ice concentration is at least 15%. Arctic has had permanent (year-round) sea ice for last 5000 years. Recent summer sea-ice extent is nearly 50% lower than 1979-2000 extent. Arctic summer sea-ice may disappear within 10 to 20 years. 2014 September sea-ice extent

32. Arctic: Polar bears live, hunt, and raise cubs on sea ice -Loss of summer ice means more energy needed for hunting, camouflage less effective

33. Polar bear survival probabilities from 2001-2006 mark-recapture data Dots indicate location of each polar bear caught Hunter et al. 2010

34. Relate population growth rate to “Ice(t)”, the number of ice-free days per year If growth rate <1, population is shrinking Need <127 ice-free days for population growth Hunter et al. 2010

35. Hunter et al. 2007 2005 2025 2045 2065 2085 2105 Projected ice-free days Extinction probability 2005 2025 2045 2065 2085 2105 10 circulation models Predict # ice-free days + Population model (depends on Ice(t)) = Population projections >80% probability of extinction by 2100

36. Latest population assessment: 1 increasing, 3 stable, 8 decreasing

37. Polar bears - current status: “Threatened” 2010: 187,000 mi 2 in Alaska, mostly sea ice area, set aside as “critical habitat” “Threatened” status can’t be used to regulate greenhouse gases or influence climate policy December 2010: President Obama denied upgrade of polar bears to “endangered” status July 2011: Federal judge agreed with President Obama, ruled that polar bears are merely “threatened”

38. New model suggests emissions cap could lessen risk of extinction Sea ice cover in September, the most ice-free month “Business as usual” 2020 Emissions cap 2020 emissions cap scenario predicts <25% extinction probability Amstrup et al. 2011

39. Antarctic sea-ice extent has increased slightly, mainly in the Ross Sea 2014 September sea-ice extent Sea ice extent is defined as the total area in which the ice concentration is at least 15 percent.

40. Although Antarctic sea ice is not shrinking on average, there are occasional large ice losses Larsen B ice sheet collapse 2002 Despite slight increases in Antarctic ice extent, large sections of ice sheets have broken off in recent years.

41. Antarctica: Emperor penguins sensitive to sea ice extent -Too much ice: Foraging trips too long, lower survival -Ice breaks up too soon: chicks die before fledging

42. -Penguin survival sensitive to changes in sea ice >36% probability of quasi-extinction (95% decline) by 2100 -“To avoid extinction, emperor penguins will have to adapt, migrate, or change the timing of their growth stages.” Jenouvrier et al. 2008 1972-1981: 11% per year reduction in sea ice 50% decline in penguin population Emperor Penguins Population model Demographic data set + Global climate models Predictions of sea ice extent = Population projections