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PRI's Environmental News Magazine

Puget Sound’s Acidic Waters

Air Date: Week of June 8, 2012

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These blooms of algae eventually sink to the bottom and decompose, releasing CO2 which makes the water more acidic. (Photo: Ashley Ahearn)

Carbon dioxide emissions are making the oceans more acidic. In Washington State’s Puget Sound, it’s been discovered that water acidity is significantly higher than the open ocean. Scientists and policymakers are scrambling to find out what’s contributing to the problem and how to take action. EarthFix’s Ashley Ahearn reports.

Transcript

CURWOOD: It's Living on Earth, I'm Steve Curwood. The oceans absorb a large portion of the carbon dioxide we release into the atmosphere from power plants and tail pipes. When it gets there, the CO2 makes the water more acidic and less hospitable for certain creatures, especially shellfish.

Puget Sound, Washington, has become sharply more acidic than the open ocean, and some shellfish hatcheries have lost thousands of dollars. The Governor of Washington State has convened a panel of experts to address ocean acidification - it’s the first of its kind in the United States. Ashley Ahearn of the public media collaborative EarthFix reports.

AHEARN: Remember those little pieces of paper you used to measure pH back in junior high school with? 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.

FEELEY: The acidity of the ocean has increased by 30 percent over the last 250 years.

AHEARN: That’s Richard Feeley. He’s a scientist with the National Oceanic and Atmospheric Administration and serves on Washington Governor Chris Gregoire’s Ocean Acidification panel. Feeley says our CO2 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.

FEELEY: 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 in our region.

The local processes Feeley’s talking about starts out in the ocean with tiny organisms that live near the surface and absorb CO2 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. The Ocean Acidification Panel recently 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.

[AIRPLANE SOUNDS STARTING UP]

KREMBS: Gonna just prepare everything because I’m going to be sitting here in the back seat because it has the biggest window so I can get good aerial shots.


Christopher Krembs, an oceanographer with the Washington Department of Ecology, surveys Puget Sound for algae blooms. (Photo: Ashley Ahearn)

[ENGINE FIRES UP]

AHEARN: Christopher Krembs is an oceanographer with the Washington Department of Ecology. Every month he flies from Seattle down to Olympia and takes photos of the waters of Puget Sound.

KREMBS: We’re going to be flying at an altitude of 2,500 feet because we get a good overview from there.

[ENGINE SOUNDS UNDERNEATH]

AHEARN: We take off from Lake Washington and head towards the coast. The city of Seattle sparkles below us, clustered along the lip of the dark blue waters of Puget Sound.
But when you look closer you see these waters aren’t all one color. Krembs starts gesticulating and pointing out the window. Below us massive blooms of algae tint the water in shades of light blue, green and even rust. White frothy lines mark where opposing currents and fronts move the clouds of algae around, sort of like fence lines along fields of different-colored crops.

[ENGINE SOUNDS LANDING]

AHEARN: When we land, Krembs says this wasn’t just an average day in the air. The blooms we saw were bigger than anything he’s photographed in Puget Sound before.

KREMBS: I’m surprised about the intensity. I have not seen that at that scale.

AHEARN: Krembs says these algae 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. Krembs 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 more acidic.

KREMBS: So if you have more nutrients then you will have more blooms, longer lasting blooms, larger blooms and that promotes basically a cycle where you have more algae sinking to the bottom, consuming more oxygen, producing more CO2, and that has also an effect on ocean acidification.

AHEARN: It’s like a never-ending cycle. More nutrients means more algae. More dead algae means more CO2 released into the water. And more CO2 means more acidic water. Scientists on the Ocean Acidification 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. It's kind of like Puget Sound is suffering from a case of heartburn.

WARREN: 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.

AHEARN: Brad Warren is with the Sustainable Fisheries Partnership. He’s part of Governor 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.


Algae blooms in the Puget Sound, Washington. (Photo: Ashley Ahearn)

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.

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 that we can figure out how to use them and manage these activities and in fact, in some cases, probably encourage them.

AHEARN: There’s more research to be done about acidification in Puget Sound but the Ocean Acidification Panel acknowledges that action needs to be taken. They will release a report outlining their recommendations at the end of the summer.

For Living on Earth, I’m Ashley Ahearn in Seattle.

 

Links

Earth Fix Website

Ashley Ahearn’s second story and audio slide show on algae and acidification, click here

 

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