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Ocean Acidification. Scott Doney Woods Hole Oceanographic Institution. Rising Atmospheric CO 2. IPCC AR5 WG1 Chap. 6. Warm interglacial. CO 2. Cold glacial. Temperature. Doney & Schimel Ann. Rev. Env . & Res. 2007. Fate of Human-Driven CO 2 Emissions ( 2003-2012).
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Ocean Acidification Scott Doney Woods Hole Oceanographic Institution
Rising Atmospheric CO2 IPCC AR5 WG1 Chap. 6 Warm interglacial CO2 Cold glacial Temperature Doney & Schimel Ann. Rev. Env. & Res. 2007
Fate of Human-Driven CO2 Emissions (2003-2012) Atmosphere 45% Land 29% + ~9.5 billion tons carbon per year Oceans 26% LeQuere et al. Earth System Sci. Data 2014 ; Global Carbon Project 2014
IPCC AR5 WG1 Chap. 6
Ocean Acidification H+ + CO3 2- HCO3 - H+ + HCO3 - CO2 + H2O 2000 30% acidity 16% [CO3 ] [CO2] CO3 2− 50 300 8.2 40 240 2100 pH 100−150% 8.1 30 180 50% 2− pH μmol kg−1 8.0 20 120 [CO3 ] 7.9 2− 10 60 CO2(aq) 0 0 7.8 1800 1900 2000 2100 Year Wolf-Gladrow et al. (1999)
Changing Seawater Chemistry carbon dioxide pH IPCC 2014 WG1, Chapter 3 Doney et al. Ann. Rev. Mar. Sci. 2009 Dore et al. PNAS 2009 carbonate ion
Calcium Carbonate Ca+ CO3 CaCO3 (solid) 2+ 2- Saturation State = [Ca2+][CO32-] / Ksp >1 saturated <1 undersaturated Excess carbonate ion Δ[CO32-] = [CO32-]obs - [CO32-]sat CaCO3 solubility -depends on mineral form -increases with pressure Feely et al. Nature 2005; Bednaršek Nature Geosci. 2012
Coastal Gulf of Maine Ocean Acidification Mooring http://www.pmel.noaa.gov/co2/story/GOM
Coastal Upwelling Barton et al. Limnol. Oceanogr. 2012
Acidification along U.S. East Coast acidic waters Depth (m) Distance From Shore (km) Wang et al. Limnology & Oceanography 2013
Other Local Sources of Acidification Doney et al. PNAS 2007; Doney Science 2010; Kelly et al. Science 2011
River Flow Affects Estuaries & Coastal Waters Varies with river chemistry (natural & pollution) Sailsbury et al. EOS 2008 Aufdenkampe et al. Frontiers in Ecology & Environment 2011
Excess Nutrients, Low Oxygen & Coastal Acidification Wallace et al., Estuarine, Coastal &Shelf Science, 2014
Marine Life Susceptible to Ocean Acidification -Reduced shell formation -Habitat loss -Less available prey
Negative Impacts of CO2 on Mollusks Present Future (estuaries) Eastern Oyster Larvae Talmage et al. PNAS 2010
Synthesis of biological impacts All types of organisms tested Detrimental Effects Kroecker et al. (2009; 2013)
Pacific NW Oyster Hatcheries Barton et al. Limnol. Oceanogr. 2012
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
Summary Points • -Atmospheric carbon dioxide (CO2) rising because of human emissions (mostly fossil fuel burning) • -About ¼ of human CO2 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
Dissolved Inorganic Carbon(DIC): total concentration of all carbon species Alkalinity: acid buffering capacity (weak anions, 2*CO32- + HCO3-) pCO2: partial pressure of carbon dioxide pH: hydrogen ion activity
Ocean Inorganic Carbon & Alkalinity Distribution Dissolved inorganic carbon (DIC) Alkalinity Vertical DIC gradient ~1/3 thermal ~2/3 biological
Projecting Future Ocean Acidification Trends IPCC AR5 WG1 Chap. 6
Anthropogenic CO2 Distribution & Uptake Sabine et al., Science, 2004; Gruber et al., GBC, 2009
How Long Will Anthropogenic Carbon Dioxide and Its Climate Impacts Persist? IPCC AR5 WG1 Chap. 6
Rising Atmospheric CO2 Ice core data “Thus human beings are now carrying out a large scale geophysical experiment…” Revelle and Suess, Tellus, 1957
Changing Seawater Chemistry Doney et al. Ann. Rev. Mar. Sci. 2009 Dore et al. PNAS 2009
