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Oysters To Serve As Biological Sensors In San Diego Estuaries

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San Diego researchers hope oysters give them a unique peek into the health of local estuaries.

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Speaker 1: 00:00 San Diego researchers will Wade into a couple of local estuaries to deliver biological sentinels oysters equipped with sensors that will monitor the bodies of water. KPBS environment reporter Eric Anderson says the scientists hope to understand a habitat that can undergo dramatic changes in a matter of hours.

Speaker 2: 00:23 That's the easy part. Luke Miller holds up an oyster the size of two fists to the rural routine. San Diego state university researcher is handling the mollusks in a lab on the Scripps institution of oceanography campus and it says TJ for Miller and Gabriela Kobach are in the midst of attaching magnets to each of the oysters shells. Cover the sensor, but leave the number three. This callback is removing the slick coding on the shell of a wild caught oysters that'll give the glue that holds the sensors a chance to get a strong grip. When the oyster opens its shell to breathe or feed the magnets on each shell will separate the sensors attached, measure how much the shell opens and how frequently it happens.

Speaker 3: 01:13 But kind of reading it's giving. There is the, the measurement between this magnet and the sensor. So if I move the sensor around, we can see that reading kinda changes. So right now it's around three 90 but as I move the sensor, it increases

Speaker 2: 01:27 being able to record how often the oyster opens a shell is valuable, especially if researchers could compare the behavior to local water conditions. They want to see how a biological creature reacts to the stress of living in an extreme environment. Scripps institution of oceanography researcher Sarah Giddings says the oysters could help researchers understand how they cope.

Speaker 3: 01:50 An estuary is a perfect environment to do this study because estuaries are where you have the meeting of the ocean with often river flow or in some cases if no river flow, there's excess heating. What that means is that you have very strong gradients that are much stronger than you see in the open ocean.

Speaker 2: 02:10 Getting says estuaries can lose access to salt water, they can heat up, they can be inundated with nutrients and dissolved oxygen levels in the water can crash in a matter of hours.

Speaker 3: 02:21 And the key thing that we're going to do is make the link to the physical parameters. So the velocity. So the currents that they're feeling, the salinity, the temperature, and importantly the dissolved oxygen that they're experiencing.

Speaker 2: 02:37 Giddings hopes to expand and refine the project. Right now, data recorded by the sensors has to be gathered by hand. Researchers actually go into the field to collect data chips from a small computer that floats above a rope and anchor that holds the oysters. If that information can be transmitted in real time, scientists could record conditions and reactions as they happen.

Speaker 3: 03:00 If we do see a direct response to their environment that we could actually use these sensors in the future to learn more about the environment. So actually use the oysters to tell us something about the environment and start to think about other organisms and other locations where we could deploy them.

Speaker 2: 03:18 Researchers are releasing the oysters in the Los Penasquitos lagoon and the Tijuana river estuary. The mollusks have zip ties glued onto their shelves so they can be attached to a float or anchor that'll give scientists data from the surface and from the estuary floor. Miller says oysters can thrive there, but they also struggle in extreme conditions. And so in those cases, they will tend to just close themselves up, completely seal themselves off from the external environment and it out. Basically wait a couple of hours. Every once in a while they'll open up a little bit and test and draw on a little bit of water, see what it tastes like in some sense, whether there's any oxygen in it. The oysters are photographed before they're released to see how they'll do this winter. And Miller says he expects all of them to come back alive. We've taken these oysters from the original asteroids as I grew up and we're going to put them back in the same estuaries. And so, um, unless conditions get particularly bad during, uh, during the spring and winter and spring periods, especially, the oxygen drops particularly low, we expect that they'll survive just fine. The oysters are being deployed soon in the Tijuana river estuary and there'll be collected this spring. When that happens, scientists will put together datasets that help them understand just how the living creatures were affected

Speaker 4: 04:31 by the changes in the local estuaries.

Speaker 1: 04:34 Joining me is KPBS environment reporter Eric Anderson and Eric, welcome. Thank you. My pleasure. If these oysters stay closed up for a long period of time, is that going to indicate to the researchers that conditions are bad at the estuary?

Speaker 4: 04:50 Um, no, but it will indicate to the researchers though is that uh, this is how a living being reacts when there are bad conditions. Uh, one thing you may or may not know about some of the local estuaries, they're all very well monitored in Tijuana for example, uh, they have monitors that send data back to a satellite 24, seven. They have a couple of those in different spots in the estuary and it sends back data like oxygen levels. Uh, some of the things that we heard about in the story, um, uh, dissolved oxygen, the salinity of the water that's in there, the temperature of the water, all those kinds of things are already being monitored and they have been for years. What the oysters do is they add this biological component, right? We have a, uh, how does a creature react when the oxygen level drops? How does a creature that thrives in this environment deal with some of these extreme weather conditions? And that's really, uh, what they're looking at.

Speaker 1: 05:51 Why did the researchers choose oysters for this experiment?

Speaker 4: 05:55 Well, two things I think, uh, is that, uh, they don't move right? So you can put them down and once you put them down, they're in the location where you put them, uh, which is an advantage and, and it's easy to put a monitor on them and it's easy to measure their, uh, biological signs. So what the researchers did here was they put magnets on the shelves. When those magnets separate, it sets off readings on their instruments. Um, so it's very, very easy to measure when they open that shell and they open that shell to breathe, to feed, to filter water, um, it'll tell them a lot about what's going on, uh, in a pretty noninvasive way. And, and it's a creature that's not going to go anywhere.

Speaker 1: 06:33 It's going to stay put. Absolutely. Now we heard why they chose the estuary because there are sometimes extreme conditions there. Now I thought that estuaries were thought of as protective zones from maritime life. Is that wrong? It's not

Speaker 4: 06:49 terribly wrong. Um, the thing you have to understand about estuaries, it's one of those, uh, biological regions that are between two extremes, right? So we have the fresh water on one side, we have the ocean water on the other side, and this is kind of where those two bodies of water mix and match. And anytime you have, um, that kind of a volatile changing system, you have some really incredible diversity, uh, creates conditions that requires a specialized plant or a specialized animal species. And that makes them really valuable because they have all this diversity because of that environment changes so much. And, and yeah, many of them are protected. But that's doesn't mean that the conditions inside the estuary are not extreme. In fact, they're, they are extreme even in a under perfect circumstances, right? We think a lot about the Tijuana river estuary and, uh, the trash that it has to deal with and the extra sediment that goes through that, that estuary and the pollution, uh, the sewage tainted water, all additional stressors that that estuary deals with, but they're also monitoring Los Penasquitos lagoon, which is up the coast. It doesn't have that particular stressor. It doesn't have all the trash and the sediment and, and, uh, the pollution. But it does have the extremes in conditions there. And so there'll be able to look at a couple of different locations and measure what's going on in both.

Speaker 1: 08:18 Now, what happens after the experiment, when the oysters are collected next brain,

Speaker 4: 08:23 one thing about this experiment is that they don't get the data right now in real time. So they have these monitors that are on the oysters and they really only will get the data if they go out to the site and collect it directly. And that's not something that's going to happen, uh, on a daily basis. Uh, I think looking forward, they'll collect these oysters, they'll measure them, they'll see how they did, they'll check it against the biological data that they recorded, um, and they'll compare it to the other data that they recorded in the estuary and kind of see where those to match up and what the cause and effect was on that behavior. But I think what they're looking for in the future is, uh, getting some sort of a system in place where they'll get that real time data, whether it's a cell signal to a cell phone tower or a satellite signal to a satellite that will allow researchers to monitor what's going on.

Speaker 4: 09:16 So maybe what they'll say is like, Hmm, curious the oysters haven't opened their shells in 18 hours. Let me go look at some of the other data and see if there has been any kind of a dramatic change. It's kind of linking those two in a real time environment that I think is where they see the real big payoff. And if researchers do find that the environmental conditions are bad enough to cause a bad reaction in maritime lifelike oysters, is there any way to change that? Well, I think that they want to understand it is the key. What they're looking for is understanding how a living being reacts to these extreme conditions that they know exist that they know happen on a regular basis. And so I think that's where the real value comes in, and it'll allow them to perhaps look at these areas in a different way because they'll have this additional biological data that they can compare with the other data that they've taken in the estuaries. I have been speaking with KPBS environment reporter Eric Anderson and Eric. Thank you. Thank you. Appreciate it.

Speaker 5: 10:29 [inaudible].

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Maureen Cavanaugh and Jade Hindmon host KPBS Midday Edition, a daily radio news magazine keeping San Diego in the know on everything from politics to the arts.