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Coastal Ocean Acidification Scott Doney Woods Hole Oceanographic Institution
Coastal Ocean Acidification !Scott Doney
Woods Hole Oceanographic Institution
Rising Atmospheric CO2
IPCC AR5 WG1 Chap. 6
0
CO2
500 1000
300
400
1500 1750 1800 1900
Year
2000
Present-day CO2 level highest in past several million years
Rate of increase 50-100 times larger than natural rates of change
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 +
Atmosphere 45%
Land 29%
Oceans 26%
Human-Driven Carbon Sources & Sinks
IPCC AR5 WG1 Chap. 6
How Long Will Anthropogenic Carbon Dioxide and Its Climate Impacts Persist?!
IPCC AR5 WG1 Chap. 6
2− [CO3 ] [CO2]
é100−150% ê 50%
2100
8.2
8.1
8.0
7.9
7.8 1800 1900 2000 2100
50
40
30
20
10
0
300
240
180
120
60
0
pH μm
ol kg−1
Year
pH
CO2(aq)
CO3 2−
é30% acidity ê16% [CO3 ]
2000
2−
Wolf-Gladrow et al. (1999)
Ocean Acidification
CO2 + H2O H+ + CO3 2- HCO3
-H+ + HCO3 -
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 Open-ocean sites exhibit seasonal cycle & clear long-term trend
Calcium Carbonate Saturation State
Ca + CO3 CaCO3 (solid) 2- 2+
More difficult to form shells at lower carbonate ion levels
Saturation State Ω= [Ca2+][CO3
2-] / Ksp Ω>1 saturated Ω<1 undersaturated
depends on mineral form
Feely et al. Nature 2005; Bednaršek Nature Geosci. 2012
Ocean Solubility and Biological Carbon Pumps!
Collapse of Pacific NW Oyster Hatcheries!
Upwelling of water with elevated CO2 due to natural & anthropogenic sources
Coastal Upwelling
Barton et al. Limnol. Oceanogr. 2012
Acidification along U.S. East Coast!
Dep
th (m
)
Wang et al. Limnology & Oceanography 2013
Distance From Shore (km)
acidic waters
http://www.pmel.noaa.gov/co2/story/GOM
Large pH & CO2 Variability in Coastal Waters
NOAA Coastal Gulf of Maine Ocean Acidification Mooring
River Flow Affects Estuaries & Coastal Waters
Sailsbury et al. EOS 2008 Aufdenkampe et al. Frontiers in Ecology & Environment 2011
Varies with river chemistry (natural & pollution)
Other Local Sources of Acidification!
Doney et al. PNAS 2007; Doney Science 2010; Kelly et al. Science 2011
Excess Nutrients, Low Oxygen & Coastal Acidification
Wallace et al., Estuarine, Coastal & Shelf Science, 2014
Elevated CO2 & Acidification in Estuaries Waquoit Bay 2008-2011 calculated parameters
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
pCO
2 (pp
mv)
0500
100015002000250030003500
MenauhantChilds River
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
Ω (a
rag)
0
1
2
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
pH (t
otal
sca
le)
7.0
7.5
8.0
McCorkle et al., in prep.
Acidification & Low Oxygen (Hypoxia) Waquoit Bay 2008-2011 calculated parameters
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
pCO
2 (pp
mv)
0500
100015002000250030003500
MenauhantChilds River
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
Ω (a
rag)
0
1
2
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
pH (t
otal
sca
le)
7.0
7.5
8.0
McCorkle et al., in prep. Oxygen (µmol/L)
0 100 200 300 400
pH (t
otal
, cal
c)
7.0
7.5
8.0
8.5
Waquoit Bay 2008 - 2010
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
Oxy
gen
(µm
ol/L
)
0
100
200
300
400 MenauhantChilds River
1/1/08 1/1/09 1/1/10 1/1/11 1/1/12
pH (t
otal
sca
le)
7.0
7.5
8.0
Summary Points -Atmospheric carbon dioxide (CO2) rising because of human emissions (mostly fossil fuel burning) -About 25% of human CO2 emissions enter the ocean, changing seawater chemistry
• more acidic (lower pH) • calcium carbonate shells more soluble
-Coastal acidification can occur because of excess nutrients (and other processes)
