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Our Acidic Ocean

AIR DATE: Tuesday, May 27th 2008
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How does the rising acidity of the ocean fit into the global climate change puzzle?

Acidity levels in the Pacific Ocean are rising faster than expected, according to a study published last week in the journal Science. A team of researchers from the Pacific Northwest as well as Canada and Mexico studied water samples up and down the coast last year and came up with some alarming results: acidity levels could become high enough to prevent shellfish from growing shells in the coming decades.

The ocean has helped temper global warming by absorbing carbon emissions from the atmosphere. That, coupled with the carbon dioxide that naturally occurs in the water, is quickly pushing the Pacific towards corrosive levels for plankton and organisms on up the food chain.

How does this new information fit into the larger global climate change puzzle? What is the best way to deal with the consequences of rising acidity levels in the ocean? How will this news impact the shellfish industry?

GUESTS:

Photo credit: mako / Flickr / Creative Commons

Tagged as: fishing · ocean

If you want to see some of the chemical interactions in greater detail than we'll get into in the show: Enjoy!
David Miller —
Who knew? Coral grows -- beautifully -- in cold water, too. For now...
David Miller —
An observation and questions: To some extent the potential consequences of global warming have tended to reduce public ecological discussions to simply questions of greenhouse gas emissions. Acidic oceans remind us that such emissions are pollution in other ways too, and that our ecological thinking needs to include other elements of sustainability and public health.

Questions: Are there other sources of oceanic acidity about which we should be thinking? Does this phenomenon point to the idea that carbon neutrality is not enough? Could plant-based carbon sinks on land ease pressure on the oceans?
Chris Lowe —
Do we know anything about ocean acidity in the geologic past, at times when atmospheric CO2 levels were high as they are today? Did the plankton community undergo any drastic changes in numbers or species composition?

Duncan Parks
xanthoptica —
An article about the study I mentioned on oxygen changes:
http://www.timesonline.co.uk/tol/news/uk/article740197.ece
David Miller —
Thanks for the link, David.

I had a look at the Turley study, and what they were referring to was organism's ability to utilize oxygen, not changes in the oxygen content of the water. Certain organisms have very high oxygen demand, and the physiological mechanism by which they transport oxygen in their bloodstream is very pH dependent.

They were referring to earlier work by Portner et al that showed this effect in fast-moving squid.

There is a nice series of articles in the August 2004 issue of the Journal of Oceanography that deals with physiological implications of ocean acidification.

bhales —
Thanks Burke, for clarifying this for David - you are quite right that I was refering to squids physiological ability to utilize oxygen from Portner's interesting work. They have a high demand for O2 becuase of their great speeds. I was NOT implying a relationship between seawater pH and O2 content!!

Congratulations to all involved in an excellent programme. If anyone wants more info on ocean acidifications check out the attached string of useful links. The EU has already funded a multi-euro programme (EPOCA) on ocean acidification http://www2.cnrs.fr/en/1208.htm, other countries are trying similar - great to hear that the USA are working hard to get science in this area funded too as there is just so much we don't know. We also need to make sure that as these national programmes get funding we work collaboratively at the international level becuase it is so urgent. Why is it urgent? We need to make sure that the issue of ocean acidification and its impacts becomes part of the climate change policy mitigation and adaptation debate for post Kyoto. The certainty level (high) about ocean acidification and the changes to ocean chemistry makes it a profoundly important argument for urgent and substantal mitigation (reduction in CO2 emissions).
CTurley —
Gov Kulongoski has a proposal to set aside Marine Estuaries off the Oregon coast to protect marine life from over-fishing and to provide a boost to the fishing industry in Oregon through overflow of larvae and eggs into non-estuary areas. Will this no-take zone program, if it moves forward, be done in vain in light of ocean acidification?
Eric Miller —
Regarding the study Emily mentioned on Southern ocean carbon dioxide uptake: Apparently, atmospheric concentration isn't the only determinant of how much is absorbed in a given region. Water stratification in a warming world and wind speeds also seem to be factors. There's certainly a lot to consider on this issue, including that acidification may have biological consequences that loop back to the climate system, since organisms like diatoms are a big part of the carbon cycle.

Speaking of which, the idea of seeding the oceans with iron came up. Although on it's face it's an exciting possibility, there is the question of real-world effectiveness. If memory serves, at least one study found that iron quickly dispersed and mixed into deep water. So it may not have much effect, at least without large, repeated applications that could have undesirable side-effects. There's also more to long-term carbon sequestration than just fertilizing phytoplankton, like water temperature and the depth to which organic material sinks. It might still help, but the best solution is getting serious with international fossil CO2 agreements and accelerating energy reform.
Alex J —

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