Ocean acidification threatens our food chain

There were a number of interesting presentations made by technical experts at the PSFMC conference. These included topics such as: (1) Ocean Conditions and Forecasting Salmon Returns; (2) Gulf Oil Spill Update; (3) Washington DC Legislative Activity Update; and (4) Ocean Acidification. I found the Ocean Acidification presentation particularly interesting and thought you might find a brief summary of what I learned interesting as well.

According to the presentation, there is strong scientific evidence that the earth’s temperature is increasing at an alarming rate. We were told at the conference that the polar icecap in the Artic will completely disappear during the summertime by as early as the year 2035. These temperature increases are being caused by the excessive release of carbon dioxide into the atmosphere which has a dramatic effect on the world’s oceans.

Carbon dioxide emissions react with seawater to form carbonic acid, imperiling the growth and reproduction of ocean species from plankton to squid. The oceans of the world soak up 30 million tons of the CO2 gas every day. As the water becomes more acidic, corals and life forms such as clams and mussels have trouble building their skeletons and shells. The acidity can also interfere with basic bodily functions such as growth and reproduction. In just the past 15 years, acidity in the upper 100 meters of the Pacific Ocean from Hawaii to Alaska has increased 6 percent.

The acidification of the earth’s oceans will ultimately mean a reduction in the food supplies. For example, the ocean fish we prefer to eat, from tuna to salmon to striped bass, depend on an abundance of small creatures known as copepods to support the prey that support the tuna and salmon. This food chain is threatened because the copepods are in jeopardy of being eliminated by ocean acidity. In a recent experiment conducted on a species of copepod common off the California coast, half the organisms died within a week of being exposed to elevated levels of acidic seawater.

Currently, there is substantial pressure within the scientific community to limit the amount of CO2 that is discharged into the atmosphere. Clearly more scientific study is needed to clarify and define the causes and problems of ocean acidification, but based on what I learned at the PSMFC conference, as regulators are setting CO2 targets, ocean acidification should be kept in mind.

Tom Harman, State Senator. 29 September 2010. Article.


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