Changing sea chemistry will hit Alaska communities hard

Originally published July 29, 2014 at 6:06 AM | Page modified July 29, 2014 at 6:07 AM

Oyster growers in the Pacific Northwest have already been stung by changes in ocean chemistry linked to greenhouse-gas emissions.

Now, a new study led by Seattle researchers finds communities in Southwest and Southeast Alaska that rely on the sea for food and jobs are also likely to be hit hard over the coming decades.

The analysis, published Tuesday in the journal Progress in Oceanography, is among the first to examine the potential social and economic impacts of ocean acidification sometimes called global warmings twin.

Just as carbon dioxide from power plants, factories and cars diffuses into the atmosphere, the gas is also absorbed by the worlds oceans. As a result, scientists say the average pH of seawater has become slightly lower, or more acidic, since the start of the industrial era.

That effect is expected to intensify in the future and some places are more vulnerable than others.

The Alaskan waters that yield much of the U.S. commercial-seafood catch are near the top of that list, said lead author Jeremy Mathis, of the National Oceanic and Atmospheric Administrations Pacific Marine Environmental Lab in Seattle.

Carbon dioxide dissolves more readily in cold water, and the Bering Sea and Gulf of Alaska are already naturally CO2-rich.

It doesnt have that far to go before it reaches this critical threshold where the water can become corrosive, Mathis said.

Thats what scientists say occurred along the Washington and Oregon coasts beginning in the mid-2000s. Naturally low pH levels dropped even further, killing oyster larvae in hatcheries that drew water from the Pacific.

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Changing sea chemistry will hit Alaska communities hard