Gallery H

Dying Shellfish

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Acidic Waters Killing The Marine Food Chain


By James Donahue


A well-written story by Ian Sample, Science Correspondent for the UK Guardian, outlined in 2005 how rising carbon dioxide levels from industrial pollution in our atmosphere is increasing the acidic content of the oceans and killing the tiny marine organisms at the bottom of the food chain.


The changes in the water are particularly affecting marine organisms that grow protective shells. Scientists warn that if greenhouse gas emissions continue unabated, “the entire Southern Ocean, which stretches north from the Antarctic coastline and sub-arctic regions of the Pacific Ocean, will soon become so acidic that the shells of marine creatures will soften and dissolve,” the story said.


It said the loss of these creatures at the lower end of the food chain could have “disastrous consequences for larger marine animals. North pacific salmon, mackerel, herring, cod and baleen whales all feed on pteropods or sea butterflies, one of the species under imminent threat.”


Carbon dioxide is a by-product from burning fossil fuels and other industrial processes. When carbon dioxide gets in the rainwater, and consequently mixes with the oceans, “it strips out carbonate ions dissolved in surface waters, so there is less available for marine organisms to build calcium carbonate shells and exoskeletons from,” Sample writes.


The story said the rise in acid content of the oceans is occurring much faster than scientists originally thought.


One study by an international team from Britain, the U.S., Japan and Australia indicated that the water would be too acidic for shell formation by 2050.


Experiments by Victoria Fabry at California State University in San Marcos showed that the shells of these sea creatures begin to dissolve rapidly when exposed to higher levels of acidic water. Pits form on the surface of the shells and then external layers peel away.


Sample wrote that the polar oceans “will be the first to feel the brunt of rising carbon dioxide levels. Atmospheric carbon dioxide has increased from pre-industrial levels of around 280 parts per million to 380 parts per million today.”


Sample’s story was but a premonition of big trouble that was about to strike the $111 million oyster industry on the U.S. West Coast. That very year most of the millions of Pacific oysters in Washington’s estuary failed to reproduce. The failure continued each year since and now has spread south as far as Los Angeles.


Scientists studying the problem are looking at shifts in ocean chemistry linked to carbon-dioxide emissions. They warn that this growing issue is imparing sea life faster and more dramatically than they had expected.


Oyster producer Brian Sheldon said that the dramatic effects of ocean acidification are a clear “sign of things being out of balance. And that scares the living daylights out of me.”