For people who depend on the oceans for their livelihood, climate change is about a lot more than weather. Some of the carbon in the atmosphere — which is gradually warming the planet — is absorbed by the oceans, making their basic chemistry more acidic, and making it difficult for organisms like mussels to build their shells. Until recently, it was difficult to measure the amount of carbon in seawater. But now, thanks to garage-laboratory ingenuity and some repurposed beer bottles, researchers at the Sitka Tribe of Alaska can keep tabs on ocean acidification around the clock. KCAW’s Katherine Rose has more.
Esther Kennedy, an environmental specialist for Sitka Tribe of Alaska, is explaining how her new “science machine” works-
“The Burke-o-Lator was made by Professor Burke Hales and some graduate students. Essentially, he puts these together in his garage,” says Kennedy. “It is very intimidating, there are a lot of tubes.”
Though it has a lot of tubes and does a lot of things, in short it measures carbon dioxide in the water to help determine the effects of ocean acidification.
“Scientists have known about global warming since the 1980’s with a lot of certainty,” Kennedy says. “But for a long time the thought was, ‘Thank goodness we have the ocean to absorb all this carbon, because otherwise things would be warming up a lot faster.’ Until suddenly people started to realize that the carbon in the ocean is starting to change its chemistry.”
They’re sucking water out of Sitka Harbor at a rate of 20 gallons per minute, through pvc pipe that travels from the float plane dock behind their building, straight into their research lab. Most of that water goes right back into the ocean, but a bit is processed through the Burke-o-Lator.
“In this equilibrator, we essentially continuously bubble the water with a closed loop of air.”
That bubbling air takes on the dissolved carbon dioxide concentration of the water going through the machine. “It’s very difficult to measure water directly, so the name of the game is how can you get all this information that you want out of water into gas,” Kennedy says. “Because if you can solve the problem of getting things into the gas phase, you can actually make high accuracy measurements.”
Kennedy, informed by her background in geology, knows that ocean acidification is serious business. “Interestingly, ocean acidification is associated with almost all the major mass extinctions in earth history, which as a geological tidbit is sort of interesting, but as relevant to the modern day is a little bit terrifying.”
When the ocean absorbs CO2, a chemical reaction happens causing carbonic acid to form. Just like the vinegar dissolving baking soda in a science class volcano, that acid dissolves aragonite, a necessary component for shell formation.
‘When you start to shift that chemistry more towards the acidic side, things can’t make shells anymore,” says Kennedy. “The point that we’re getting to now and will continue to reach as an organism can’t make the shell in the first place or it takes so much energy to make a shell, that you have no energy left to do anything else, like reproduce.”
And not just that. Kennedy says ocean acidity may affect how salmon navigate, and she says Alaska is potentially more vulnerable than other places, because our water is cold. Cold water absorbs more CO2. “We are one of a bunch of other groups in Alaska that are starting to look really closely on ocean acidification’s effects on where people live…right now.”
And while the Burke-o-Lator is constantly measuring ocean water from Sitka Harbor, it can also measure the acidity in individual samples from around Baranof Island. How can people collect those samples? Beer bottles.
“If you’re going to collect a water sample for ocean acidification, you don’t want it to exchange air with the atmosphere, so beer bottles are a great way to do that, because they have no gas exchange, and they’re cheap and they’re easy,” says Kennedy.
They’ve been collecting data with the Burke-o-Lator since June, and Kennedy says there have been some interesting findings so far. Shell makers have an easier time in the summer because the saturation of aragonite is high. The water becomes more acidic in the winter months, when photosynthetic plankton aren’t in bloom to help absorb CO2. And water is more acidic at high tides, too.
But overall, it will be a few years before researchers determine the larger trends of ocean acidification in Sitka’s waters, and the threat it poses to the marine ecosystem. Til then, they’ll keep the Burke-o-Lator purring in the lab, one beer bottle at a time.