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?

● 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?

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, FijiCredit: 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

• More funding• Cross-group and transnational collaboration• Public Awareness• Cutting CO2 emissions• Taxing carbon emissions• Alternative energies• Climate change conference in Copenhagen