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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

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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

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

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Recall the severe 1997-98 El Nio Maximum temperature anomalies ~3 C

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

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

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IPCC Report 2007

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Sea Level Rise Cazenave and Llovel, 2010, Annu. Rev. Mar. Sci. 2010. 2:145173 Do you remember the main causes of sea-level rise?

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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.

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

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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

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

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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

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Many species must move to survive ocean warming

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

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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)

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

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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.

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

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Healthy corals have Zooxanthellae -Symbiotic unicellular algae -Photosynthetic -Algal pigments provide coral color -Provide up to 90% of corals 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

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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)

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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

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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

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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

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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

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

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

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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

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

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

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Relate population growth rate to Ice(t), the number of ice-free days per year If growth rate 80% probability of extinction by 2100

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

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Polar bears - current status: Threatened 2010: 187,000 mi 2 in Alaska, mostly sea ice area, set aside as critical habitat Threatened status cant 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

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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

-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