Download - Ocean Acidification
Ocean Acidification Scott Doney
Woods Hole Oceanographic Institution
Rising Atmospheric CO2
IPCC AR5 WG1 Chap. 6
Doney & Schimel Ann. Rev. Env. & Res. 2007
Warm interglacial
Cold glacial
CO2
Temperature
Fate of Human-Driven CO2 Emissions (2003-2012)
LeQuere et al. Earth System Sci. Data 2014 ; Global Carbon Project 2014
~9.5 billion tons carbon per year+
Atmosphere45%
Land29%
Oceans26%
Human-Driven Carbon Sources & Sinks
IPCC AR5 WG1 Chap. 6
2−[CO3 ][CO2]
100−150% 50%
2100
8.2
8.1
8.0
7.9
7.81800 1900 2000 2100
50
40
30
20
10
0
300
240
180
120
60
0
pHμm
ol kg−1
Year
pH
CO2(aq)
CO32−
30% acidity16% [CO3 ]
2000
2−
Wolf-Gladrow et al. (1999)
Ocean Acidification
CO2 + H2O H+ + CO32- HCO3
-H+ + HCO3-
Changing Seawater Chemistry
IPCC 2014WG1, Chapter 3Doney et al. Ann. Rev. Mar. Sci. 2009Dore et al. PNAS 2009
carbonate ion
pH
carbon dioxide
Calcium Carbonate
Ca + CO3 CaCO3 (solid)2-2+
Saturation State
= [Ca2+][CO32-] / Ksp
>1 saturated<1 undersaturated
Excess carbonate ion Δ[CO3
2-] = [CO32-]obs - [CO3
2-]sat
CaCO3 solubility -depends on mineral form-increases with pressure
Feely et al. Nature 2005; Bednaršek Nature Geosci. 2012
Ocean Solubility and Biological Carbon Pumps
http://www.pmel.noaa.gov/co2/story/GOM
Coastal Gulf of Maine Ocean Acidification Mooring
Collapse of Pacific NW Oyster Hatcheries
Coastal Upwelling
Barton et al.Limnol. Oceanogr.2012
Acidification along U.S. East Coast
De
pth
(m
)
Wang et al. Limnology & Oceanography 2013
Distance From Shore (km)
acidic waters
Other Local Sources of Acidification
Doney et al. PNAS 2007; Doney Science 2010; Kelly et al. Science 2011
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
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
Talmage et al. PNAS 2010
Present
Future(estuaries)
Eastern Oyster Larvae
Synthesis of biological impacts
Kroecker et al. (2009; 2013)
Detrimental Effects
All types of organisms tested
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
Extra Slides
Dissolved Inorganic Carbon (DIC): total concentration of all carbon speciesAlkalinity: acid buffering capacity (weak anions, 2*CO3
2- + HCO3-)
pCO2: partial pressure of carbon dioxidepH: 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
“Thus human beings are now carrying out a large scale geophysical experiment…”Revelle and Suess, Tellus, 1957
Rising Atmospheric CO2
Ice core data
Changing Seawater Chemistry
Doney et al. Ann. Rev. Mar. Sci. 2009Dore et al. PNAS 2009