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Ocean Acidification:
The Other CO2 Problem
The oceans absorb more than 25 percent of anthropogenic CO2, eventually
lowering the pH of seawater and the availability of carbonate ion, which coral
reefs and other organisms need to build their shells and skeletons.
The pH of the oceans has fallen from 8.2 to 8.1 since
the industrial revolution, a 30% increase in acidity. PH is
expected to fall another .3 to .4 units this century.
As levels of carbonate ion decline, the oceans are
becoming undersaturated with respect to the mineral
aragonite, especially at the poles.
A pteropod in normal seawater, pH
8.1-8.2 (pH 7 is neutral)
A pteropod placed in a bath of acidic seawater
undersaturated with respect to aragonite, (a) shows a
normal shell; (b-e) shows its pitted and corroded edges
after a 48 hour acid bath.
Coccolithophores grown in a tank equilibrated to an
“atmosphere” with CO2 levels at 800 ppm (double modern
day levels) also show degraded shells.
Impacts on Marine Organisms
• Slows calcification rates
• Reduces metabolic rate and oxygen transport
capacity
• Interferes with ability to navigate using olfactory cues
• Cascading effects throughout ecosystems
And … Increases Photosynthetic Rates
Lessons From the Past:
the knowledge at hand
What do studies of past climate allow scientists
to predict for the future?
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Can an increase of atmospheric CO2 be directly
linked to higher ocean acidity?
What are the effects of lower oceanic pH levels on
sea creatures?
Do we have a precedent for today's ocean
acidification?
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Economic Costs
Ocean acidification reduces carbon uptake
capacities.
- Problematic because ocean acts as a huge
carbon sink, taking up about a third of CO2
emissions:
- Therefore, it becomes more expensive to mitigate
the effects of CO2 on climate change
- Oceans provides the world a service worth
between $90 to 600 billion per year, simply in
terms of carbon sequestration
Carbon Capture and Sequestration may not be the best
thing for the oceans.
Ocean acidification harms the
homes of countless living
organisms
-Detrimental to calcium carbonate
precipitation, therefore harming
reefs
-Coral reefs are of tremendous
value because they serve as
habitats for many fish, protect
coastlines, and provide people
with recreational
opportunities. Their global
economic value is $30 billion
per year. Their loss is
projected to result in a 0.18%
loss of global GDP in 2100.
Namena Marine Reserve, Fiji
Credit: Nicholas McLaren
Research Obstacles
• Lack of standardization in
experiment design
– Difficult to replicate
experiments
– Limitation to the validity
of findings
• Not enough funding
– Facilities with the
capacity to conduct the
necessary measurements
for experiments are
expensive and there is a
need for more of them
Aquarius Undersea Laboratory
Credit: NOAA
Next Steps
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More funding
Cross-group and transnational collaboration
Public Awareness
Cutting CO2 emissions
Taxing carbon emissions
Alternative energies
Climate change conference in Copenhagen