Ocean Acidification
Jan Newton
University of Washington
Station Mauna Loa
Ocean Acidification:
A story revealed to us by
a volcano and the oyster….
Station Mauna Loa
Increasing CO2 in the atmosphere
Station Mauna Loa
Increasing CO2 in the atmosphere
400
CO2 (ppm)
375
350
Charles
David
Keeling
325
300
Mauna Loa atmospheric CO2
275
1950
1960
1970
1980
1990
Year
2000
2010
Station Mauna Loa
Increasing CO2 in the atmosphere
400
CO2 (ppm)
375
350
Charles
David
Keeling
325
300
Mauna Loa atmospheric CO2
275
1950
1960
1970
1980
1990
Year
2000
2010
Station Mauna Loa
Station Aloha
pCO2 (μatm)
CO2 absorbed by the ocean
pCO2 is the CO2 gas
content of the air
or water
Doney, Science, 2010
Dore et al., PNAS 2009
pH
Station Mauna Loa
Oceans are an important sink for the CO2
Source: Le Quéré et al. 2012; Global Carbon Project 2012
Ocean acidification
Climate change
Carbon Dioxide
(CO2)
Ocean acidification
The ocean has adsorbed
about 25-30% of carbon
dioxide emitted by industry
and deforestation.
Sarah R. Cooley ([email protected])
Ocean acidification
Climate change
Carbon Dioxide
(CO2)
Ocean acidification
This creates an acidic
reaction that lowers pH
and decreases carbonate
levels in the ocean.
Sarah R. Cooley ([email protected])
The pH scale: How we measure acidity
More
acidic
Battery acid
Lemon juice
Vinegar
Beer and Wine
neutral
Milk
Human blood (7.35-7.45)
Seawater (8.1-8.2)
Milk of magnesia
More
alkaline
or basic
Ammonia
Lye
pH is a logarithmic scale
so that a pH change of 1
unit means a 10-fold
change in acidity
In other words, small
changes in pH units
mean much larger
changes in acidity!
The pH scale: How we measure acidity
More
acidic
Battery acid
Lemon juice
Vinegar
Beer and Wine
neutral
Milk
Human blood (7.35-7.45)
Seawater (8.1-8.2)
acidification
Milk of magnesia
More
alkaline
or basic
Ammonia
Lye
History and future of OA at the ocean surface
pH
8.2
pH
8.0
7.9
7.8
1800
CO2(aq)
1900
Year
2000
300
40
240
30
180
20
120
10
60
0
2100
CO2 and carbonate ion
concentrations
8.1
CO32−
2000
30% acidity
16% [CO2−
3 ]
50
0
Wolf-Gladrow et al. (1999)
History and future of OA at the ocean surface
pH
8.2
pH
8.0
7.9
7.8
1800
CO2(aq)
2100
150−200%
 50%
1900
Year
2000
300
40
240
30
180
20
120
10
60
0
2100
CO2 and carbonate ion
concentrations
8.1
CO32−
2000
30% acidity
16% [CO2−
3 ]
50
0
Wolf-Gladrow et al. (1999)
Ocean Acidification
CO2 added to seawater changes the
water chemistry, reducing the pH and
carbonate levels in the ocean
Image: Wikipedia
Ocean Acidification:
A story revealed to us by
a volcano and the oyster….
Station Mauna Loa
Is OA affecting oyster survival?
Oyster larvae
Production is lower
with lower pH
Growth in feeding stage
slower with lower pH
Barton et al., 2012
Oyster larvae
Production is lower
with lower pH
Growth in feeding stage
slower with lower pH
Waldbusser, OSU
Barton et al., 2012
Ocean Acidification: what we know
1. Atmospheric CO2 has increased from human activity
2. The oceans absorb CO2
3. The increased CO2 causes ocean acidification (OA); this
changes the water chemistry, reducing the pH and
carbonate levels in the ocean
4. OA reduces growth and survivorship in some organisms
OA is
a global condition
with
local effects
Global condition
OA trend consistent across ocean basins
Canary Is.
Bermuda
pCO2
pH
Source: IPCC 2013
[Carbonate]
Hawaii
Local effects
WA Blue Ribbon Panel Report, 2012
Ocean Acidification: Upwelling
Distance from shore (km)
Depth (m)
salinity
[O2]
(μmol/L)
Ωaragonite
West Coast
East Coast
Jiang et al., L&O, 2010
Seasonal upwelling brings high CO2,
low pH water to surface
Wind
Stress
Offshore water
displacement due to
earth’s
rotation
Upwelling
Image: NOAA PMEL
Processes that fuel increased respiration yield
higher CO2 and lower pH
CO2
CO2
Photosynthesis consumes CO2
at the surface
CO2
Respiration releases
CO2 near the bottom
Image: NOAA PMEL
Are local stressors contributing too?
Kelly et al. (2011) Science
Implications for Marine Food Webs &
Ecosystem Services
Many biological processes are sensitive to
changes associated with OA.
These include:
• Increased mortality among pteropods
(a type of plankton)
• Impacts on the nervous system of some fish
• Potential increase in toxicity of harmful algal
blooms
• Potential loss of water quality benefits
provided by shellfish, which filter nutrients
out of marine waters
Pteropod
Photo: Russ Hopcroft
Implications for Marine Food Webs &
Ecosystem Services
Some responses could
help us meet the
challenge locally.
These include:
• Seagrasses and kelps
could partially mitigate
local effects
• Some species may be
able to adapt
Photo: T. Klinger
The rate of change is rapid
Oct. 2012 CO2 level: 391 ppm
Figure source: http://www.globalwarmingart.com, based on published data through 2000
Rate of change
is important
Hönisch et al., Science, 2012
Ocean Acidification: Future directions
• What determines local nearshore CO2
levels? How can CO2 levels be measured
easily and quickly?
• What management can reduce local OA?
• How fast and far can species acclimate
and adapt?
• Where are the crucial tipping points?
• Which ecosystems are more or less
resilient?