Algae and Puget Sound Acidification Linked
The ocean absorbs a large portion of the CO2 that we release into the atmosphere from our power plants and tail pipes. But when it gets there that CO2 makes the water more acidic and less hospitable for some creatures, like shellfish. In Puget Sound some shellfish hatcheries have already lost millions of oyster larvae because of exposure to acidic water.
Ocean acidification has scientists and policymakers in the Northwest concerned. Washington Governor Chris Gregoire has convened a panel on Ocean Acidification, which met this week. Ashley Ahearn reports.
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.
Feeley: “The acidity of the ocean has increased by 30 % over the last 250 years.”
That’s Richard Feeley. He’s a scientist with the National Oceanic and Atmospheric Administration and serves on Governor 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 here 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.
Scientists are starting to look closer to home.
Krembs: “Gonna just prepare everything because I’m going to be sitting here in the back seat because it has the best window so I can get better aerial shots.”
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 2500 feet because we get a good overview from there.”
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.
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.”
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: “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 Governor Gregoire’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.
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.”
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.
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 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.
They will release a report outlining their recommendations at the end of the summer.
Copyright 2012 Northwest Public Radio