1. Ocean Acidification Scott Doney Woods Hole Oceanographic Institution

2. Rising Atmospheric CO 2 IPCC AR5 WG1 Chap. 6 Doney & Schimel Ann. Rev. Env. & Res. 2007 Warm interglacial Cold glacial CO 2 Temperature

3. Fate of Human-Driven CO 2 Emissions (2003-2012) LeQuere et al. Earth System Sci. Data 2014 ; Global Carbon Project 2014 ~9.5 billion tons carbon per year + Atmosphere 45% Land 29% Oceans 26%

4. Human-Driven Carbon Sources & Sinks

5. IPCC AR5 WG1 Chap. 6

6. 2− [CO 3 ][CO 2 ]  100−150%  50% 2100 8.2 8.1 8.0 7.9 7.8 1800190020002100 50 40 30 20 10 0 300 240 180 120 60 0 pH μmol kg −1 Year pH CO 2(aq) CO 3 2−  30% acidity  16% [CO 3 ] 2000 2− Wolf-Gladrow et al. (1999) Ocean Acidification CO 2 + H 2 OH + + CO 3 2- HCO 3 - H + + HCO 3 -

7. Changing Seawater Chemistry IPCC 2014 WG1, Chapter 3 Doney et al. Ann. Rev. Mar. Sci. 2009 Dore et al. PNAS 2009 carbonate ion pH carbon dioxide

8. Calcium Carbonate Ca + CO 3 CaCO 3 (solid) 2-2+ Saturation State  = [Ca 2+ ][CO 3 2- ] / K sp  >1 saturated  <1 undersaturated Excess carbonate ion Δ[CO 3 2- ] = [CO 3 2- ] obs - [CO 3 2- ] sat CaCO 3 solubility -depends on mineral form -increases with pressure Feely et al. Nature 2005; Bednaršek Nature Geosci. 2012

9. Ocean Solubility and Biological Carbon Pumps

10. http://www.pmel.noaa.gov/co2/story/GOM Coastal Gulf of Maine Ocean Acidification Mooring

11. Collapse of Pacific NW Oyster Hatcheries

12. Coastal Upwelling Barton et al. Limnol. Oceanogr. 2012

13. Acidification along U.S. East Coast Depth (m) Wang et al. Limnology & Oceanography 2013 Distance From Shore (km) acidic waters

14. Other Local Sources of Acidification Doney et al. PNAS 2007; Doney Science 2010; Kelly et al. Science 2011

15. River Flow Affects Estuaries & Coastal Waters Sailsbury et al. EOS 2008 Varies with river chemistry (natural & pollution) Aufdenkampe et al. Frontiers in Ecology & Environment 2011

16. Excess Nutrients, Low Oxygen & Coastal Acidification Wallace et al., Estuarine, Coastal & Shelf Science, 2014

17. Marine Life Susceptible to Ocean Acidification -Reduced shell formation -Habitat loss -Less available prey

18. Negative Impacts of CO 2 on Mollusks Talmage et al. PNAS 2010 Present Future (estuaries) Eastern Oyster Larvae

19. Synthesis of biological impacts Kroecker et al. (2009; 2013) Detrimental Effects All types of organisms tested

20. Pacific NW Oyster Hatcheries Barton et al. Limnol. Oceanogr. 2012

21. Acidification & Past Geologic Extinction Events Time moving forward to the left Hönisch et al. Science 2012 Calcareous organism response not uniform; importance of other environmental factors to extinction, adaptation & evolution

22. Summary Points -Atmospheric carbon dioxide (CO 2 ) rising because of human emissions (mostly fossil fuel burning) -About ¼ of human CO 2 emissions enter the ocean, changing seawater chemistry more acidic (lower pH) calcium carbonate shells more soluble -Coastal acidificatoin can occur because of excess nutrients (and other processes) -Acidification potentially threatens many shellfish

23. Extra Slides

24. Dissolved Inorganic Carbon (DIC): total concentration of all carbon species Alkalinity: acid buffering capacity (weak anions, 2*CO 3 2- + HCO 3 - ) pCO 2 : partial pressure of carbon dioxide pH: hydrogen ion activity

25. Ocean Inorganic Carbon & Alkalinity Distribution Dissolved inorganic carbon (DIC) Alkalinity Vertical DIC gradient ~1/3 thermal ~2/3 biological

26. Projecting Future Ocean Acidification Trends IPCC AR5 WG1 Chap. 6

28. Anthropogenic CO 2 Distribution & Uptake Sabine et al., Science, 2004; Gruber et al., GBC, 2009

29. How Long Will Anthropogenic Carbon Dioxide and Its Climate Impacts Persist? IPCC AR5 WG1 Chap. 6

30. “Thus human beings are now carrying out a large scale geophysical experiment…” Revelle and Suess, Tellus, 1957 Rising Atmospheric CO 2 Ice core data

31. Changing Seawater Chemistry Doney et al. Ann. Rev. Mar. Sci. 2009 Dore et al. PNAS 2009