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Ending Puget Sound’s Bad Acid Trip

May 24, 2012 | KUOW
CONTRIBUTED BY:
Ashley Ahearn

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  • Harvesting oyster beds at Penrose State Park on Puget Sound. Oyster growers say rising acidification is harming shellfish in the Sound. credit: Flickr/Renelle Broughton
Harvesting oyster beds at Penrose State Park on Puget Sound. Oyster growers say rising acidification is harming shellfish in the Sound. | credit: Flickr/Renelle Broughton | rollover image for more

SEATTLE — Remember those little pieces of paper you used to measure pH back in junior high school? You’d stick them into your can of Coke or on your tongue and the color would tell you how acidic that liquid was?

Well if you stuck litmus paper into the world’s oceans it would come out closer and closer to the acidic side of the pH scale.

The acidity of the ocean has increased by 30 percent over the last 250 years, says scientist Richard Feeley. He’s with the National Oceanic and Atmospheric Administration and serves on Gov. Chris Gregoire’s Ocean Acidification panel.

Feeley says our carbon dioxide emissions are making the world’s oceans more acidic. But if you did the litmus test on Puget Sound you’d see the effects here are even more severe.

“In Puget Sound we see that same impact as we see in the open ocean but we also have other combined impacts that are part of the natural local processes here in our region,” he says.

The local processes Feeley’s talking about start out in the ocean with tiny organisms that live near the surface and absorb carbon dioxide from the air. When they die they sink to the bottom and release that CO2 into the depths.

But that acidic water doesn’t stay down there. Natural ocean currents push it up and towards the shore in a process called coastal upwelling. Those deep more-acidic ocean waters eventually flow into Puget Sound.

Once they get here they tend to stick around longer than they would on the outer coast. And that makes Puget Sound significantly more acidic than the open ocean.

This week Gregoire’s Ocean Acidification Panel met to discuss the problem and what’s to be done about it. First order of business: figure out where exactly the CO2 is coming from.

Scientists are starting to look closer to home. And they’re connecting the dots they see in and around Puget Sound.

Algae blooms — which a scientist has been documenting for the Washington Department of Ecology (see related story) — love all the nutrients that humans around Puget Sound are adding to the water.

The algae thrive on the nitrates and phosphorous from our wastewater treatment plants, leaky septic tanks and runoff from fertilized lawns and agricultural lands.

Christopher Krembs is an oceanographer with the Washington Department of Ecology. He says over the past decade there’s been a steady and significant increase in nutrient levels in Puget Sound.

And that, he explains, is making the water even more acidic:

“If you have more nutrients you will have more blooms, longer lasting blooms, larger lasting blooms and that promotes a cycle where you have more algae sinking to the bottom, consuming more oxygen producing more CO2 and that has an effect on ocean acidification.”

It’s like a never ending cycle. More nutrients means more algae. More dead algae means more CO2 released into the water. More CO2 means more acidic water.

Scientists on the governor’s panel believe algal blooms could be a major contributor to the increasingly acidic waters of Puget Sound, but it’s too soon to say how big.

Its kind of like Puget Sound is suffering from a case of heartburn.

“It would be nice if there were a Rolaid. There might be highly localized Rolaids that we can apply. There will be no broad one,” says Brad Warren. He’s with the Sustainable Fisheries Partnership. Warren also is part of Gregoire’s panel on Ocean Acidification and is leading the efforts to figure out how to respond to the problem. Warren suggests first of all: cracking down on the amount of nutrients and pollution we allow into our waterways.

But Puget Sound already has heartburn — so how do we make the water less acidic?

Some people have proposed harvesting those algal blooms to make biofuel out of them before they have a chance to decompose and turn the water more acidic.

Others have suggested planting seaweeds or other grasses to suck CO2 out of the water – just like we plant trees on land to suck CO2 out of the air.

Brad Warren: “Any of these activities that we engage in that are going to change how carbon moves through the ocean are going to matter and we need to understand how so we can figure out how to use them and manage these activities and in fact, in some cases, probably encourage them.”

There’s more research to be done about acidification in Puget Sound but the Ocean Acidification Panel acknowledges that action needs to be taken.

It will release a report outlining recommendations at the end of the summer.

© 2012 KUOW
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