Increasingly acidic ocean threatens fish

Alaska’s rich fisheries are the mainstay of our coastal communities, providing for livelihoods we love and a way of life most Americans cannot even imagine. In Alaska, we pride ourselves on science-based fisheries management. So when scientists go out of their way to alert us to the dangers of ocean acidification, we need to really listen. And our elected officials need to act.

Last year 150 scientists from 26 nations posted a consensus statement called the Monaco Declaration stating they are “deeply concerned by recent, rapid changes in ocean chemistry and their potential within decades to severely affect marine organisms, food webs, biodiversity and fisheries.”

The scientific findings are clear enough. The chemical composition of seawater is changing as a result of carbon dioxide emissions from the burning of fossil fuels. This is because the ocean naturally absorbs carbon dioxide from the air. When CO2 mixes with sea water a chemical reaction occurs that lowers the pH.

This has been going on since the beginning of time but the significant increase in global CO2 emissions is overwhelming the ocean’s chemical equilibrium. The Monaco Declaration states that this has made the world’s oceans 30 percent more acidic than they were prior to the industrial revolution. Scientists report that half of that increase has occurred in the last 30 years.

Most of us aren’t chemists, but it’s not hard to understand that a more acidic ocean will change what can live there. The pH scale for measuring how acidic or alkaline the water is resembles the Richter scale for measuring earthquakes. Sea water is generally alkaline — or at the middle of the scale. The more acidic the ocean becomes, the less calcium carbonate is available to marine life for building shells and skeletal structures. Think corals, crabs, clams, certain zooplankton.

Dave Kubiak, Anchorage Daily News, 9 December 2009. Full article.

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