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  • This small shellfish has a superpower.

  • Not only can oysters make pearls out of grains of sand and taste incredible on the half shell.

  • They can also completely transform their environment.

  • One oyster can filter up to 50 gallons of water in a single day, leaving it cleaner and

  • healthier.

  • These amazing shellfish are like the natural cleaning crew of the ocean.

  • But ocean acidification and other climate-related changes are threatening oyster populations,

  • which could be problematic for their entire ocean ecosystem.

  • The world's oceans work like a giant sponge soaking in heat energy and carbon dioxide

  • from the atmosphere.

  • And while this may actually help to mitigate some of the effects of climate change on land

  • that extra heat and co2 is affecting the natural chemical balance of the ocean.

  • And so all that carbon dioxide that we put into the atmosphere, about a third of it goes

  • straight into the ocean.

  • And that carbon dioxide is fundamentally changing the chemistry of the ocean, and that's the

  • phenomenon that we call ocean acidification.

  • And how this acidification or change in the ocean's pH balance is going to impact the

  • ocean's smallest creatures is a major focus of Dr. Hill's research.

  • So what we see in laboratory experiments that we've done here at the Bodega Marine Lab is

  • that the more and more acidic the water gets, the stronger negative response you get from animals.

  • Animals like oysters and mussels tend to grow smaller, thinner shells.

  • 25 miles down the road from Dr. Hill's lab, oyster farmer Terry Sawyer was noticing something

  • similar with his oysters - that they were dying at higher rates, and at the deaths were in

  • correlation with high acidification of the water where they were growing.

  • So when Terry and Dr. Hill met at a conference, something clicked.

  • So Dr. Hill and I were like looking at each other like wait...

  • Dr. Hill is based out of Bodega Laboratory just in the north of here 45 minutes away,

  • we're here, we're in the water all the time.

  • We do a lot of

  • thinking about sort of how to translate that work from what we know about the native oyster

  • to the oysters that they are growing

  • at the farm.

  • With the resources and daily data Terry and his team are able to gather in the

  • farm, they're able to track in real time how water chemistry is impacting oyster yields,

  • which obviously benefits Terry's business, but can also lead to a greater understanding

  • of the world's marine life.

  • And what that data is showing is that the high carbon dioxide

  • levels are making it difficult for oysters to grow their shells.

  • And if oysters can't grow strong shells many won't survive to maturity, which means a blow

  • to the oyster economy, but also to the health of our oceans.

  • Lowering of the pH.

  • the acidifying of the water is directly related to the amount of co2 that's produced by the

  • anthropogenic activities, burning of fossil fuel, co2, greenhouse gases, etc.

  • All of these things are being produced by a lot of activities we have.

  • What happens is the carbon dioxide mixes into the surface water of the ocean and forms carbonic acid.

  • This then dissolves into bicarbonate and a whole bunch of extra hydrogen ions.

  • It's these hydrogen ions that cause the real problem here.

  • As animals are trying to build their shell material, they're actually pulling the building

  • blocks of that shell material out of the water column.

  • And so they're building their shell from, for example, a calcium ion and a carbonate ion.

  • Marine bivalves like

  • oysters combine the calcium ions and the carbonate ions into solid crystals of calcium

  • carbonate that they use to form their shells, but hydrogen ions from the dissolved co2 in

  • the ocean have a tendency to bond with the carbonate ions, leaving fewer available for

  • the newly spawned oysters.

  • The vulnerable stages of any organism are at the larval stage.

  • And so if you start affecting how hard it is for that organism to live. In this case

  • for an oyster to build a shell, then that's going to lead to problems with it being able

  • to be a viable organism.

  • Basically, the more energy the oyster has to waste competing with hydrogen ions for

  • shell material, the less energy it has for growing big and strong.

  • It can also result in a weaker shell,

  • so that shell now is compromised where it's too thin or breaks easily, then it can no

  • longer seal itself out, seal that that poor water quality out and they will not be viable.

  • Terry and Dr. Hill are also working together to actually simulate future water conditions

  • in the lab, in order to try to predict what may happen to oysters

  • in the coming decades,

  • We built almost a decade ago, built an experimental setup that kind of operates like a time machine.

  • We can dial in today's carbon dioxide values in a tank.

  • And then in the tank next door we can actually ramp it up and maybe put the carbon dioxide

  • concentrations that you'd see in 100 years

  • with acidification levels rising 30% since the Industrial Revolution, it's critical to

  • be tracking the problem now, and try to work on how to be ready for

  • the future.

  • Oftentimes when you hear about ocean acidification,

  • it seems like this sort of distant chemical problem that the ocean is experiencing.

  • And if you go to Hog Island Oyster Company and you have, you know you're sitting at a

  • picnic table and you have lunch sitting in front of you, all the sudden we can talk about

  • ocean acidification in a way that's about a family business, and a coastal economy,

  • and the food on our plates, and a future that we want for our kids.

  • This data from the lab and the data collected by instruments placed at the farm itself,

  • all help Terry address acidification by knowing precisely when the pH differences lead to

  • high mortality rates.

  • From this, he can figure out which oyster strains are more resilient

  • than others.

  • But this won't solve the problem outright.

  • In the end it all comes down to the carbon dioxide that's blasting nonstop into the atmosphere

  • and getting soaked up by the ocean.

  • I think ocean acidification is a problem that we can confront and change the course of the

  • problem.

  • So, just like the other issues that we are dealing with with climate change, the fundamental

  • issue is our carbon dioxide emissions.

  • More people need to be aware of this and what has change look like.

  • It actually means a lot of changes in our behaviors.

  • And that means everything from efficiencies, on how we run our heating systems to producing

  • electricity as to how we get around.

  • And I think the other part of this is just know that the collective energy would have

  • an amazing impact.

  • And I think that's really the important part is that there is something that people can do

This small shellfish has a superpower.

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What Ocean Time Machine Experiments Predict About Oysters

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    林宜悉 posted on 2020/10/27
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