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Ocean is becoming too toxic for oysters

Chris Alemany, Alberni Valley Times, April 18, 2012

Imagine if a farmer couldn't raise cattle in his field because the air was too toxic.

People who dispute global warming always claim that scientists are "alarmists" and that they are exaggerating the truth. Well, here is another "alarmist" headline for you. The Ocean is becoming toxic for oysters.

From research published in the journal Limnology and Oceanography last week: "Rising atmospheric carbon dioxide driven by anthropogenic [human-industry] emissions has resulted in the addition of over 140Pg-C [petagrams of Carbon or 140 with 15 zeros after it) to the ocean. For the observed change between current-day and preindustrial atmospheric CO2, the surface oceans have decreased in pH by 0.1 unit, although colder surface waters are likely to have experienced a greater effect.

"We report results from an oyster hatchery on the Oregon coast - Both larval production and midstage growth of the oyster Crassostrea gigas were significantly negatively correlated with the aragonite saturation state of waters in which larval oysters were spawned and reared for the first 48 hours of life."

In other words, the lower pH and higher acidity of the water is causing oyster larvae to die before they can form their shells.

Oysters appear to be the most sensitive, but the study also notes that muscles and clams show negative responses as well. Scientists have been warning us that this would happen and we continue to ignore and dispute them, and now, the evidence is starting to appear.

This Earth Day I hope you can your support local shellfish growers and enjoy an oyster.

Chris Alemany
Port Alberni

© Alberni Valley Times 2012