Coos Bay researchers use tea bags to understand marsh health - OPB

2022-10-02 22:45:11 By : Mr. Allen Bao

About three months ago, scientists buried tea bags at the Metcalf Marsh. They are doing this to get a better understanding of how climate change might be affecting decomposition and carbon storage.

Researchers at Oregon’s South Slough National Estuarine Research Reserve are importing teabags from the UK, but they’re not using it to brew a cup of tea in between studies. These tea bags are being used to get a better understanding of what carbon storage is like in the marshes and wetlands outside of Coos Bay. The bags were buried underground in the start of the summer and were recently dug up to examine how much they have decomposed and see how much climate change is affecting the decomposition process. Shon Schooler is the Lead Scientist for the reserve and Colleen Walker is their fall intern. They both join us to share the work they’re doing at the Slough.

Note: The following transcript was created by a computer and edited by a volunteer.

Dave Miller: This is Think Out Loud on OPB, I’m Dave Miller. When we started planning for our trip here to Coos Bay, we heard that some researchers were sticking tea bags into the damp ground of the marshes and wetlands a little south of town, and we wanted to know what they were doing and what they were hoping to learn. So we met up with Shon Schooler, the lead scientist for the South Slough Estuarine Research Reserve and Colleen Walker who is a fall Intern there. They let us borrow some knee high rubber boots and took us to a marine wetland to watch them work. I had Shon describe where we were.

Shon Schooler: We’re in a place called Metcalf Marsh, which is near Charleston, Oregon, and it’s a restored tidal marsh. We call it ‘low marsh’ because it has certain types of plants that are adapted to saltwater.

Miller: My understanding is that the reserves that you are the lead scientist on there, It was the first area of its kind to be named after a federal law passed in 1972. What makes this area special broadly? Why was this area chosen?

Schooler: It was chosen because a lot of the original marshes are still pretty much intact and so they chose it so that they could preserve it, these marsh systems, and then protect them for the future.

Miller: Who lives here. I mean, what is this the habitat for?

Schooler: This would be a habitat for, well, when it’s dry...there’s two different conditions. When it’s dry, it’s a habitat for deer and elk, things like that, beaver, nutria, when it’s wet, the fish come in and they’ll, when you have a high tide, the fish come in and they’ll feed within this all across this low marsh.

Miller: So right now, I mean we’re, we’re wearing waders and it seems sort of moist, but we can walk around here. So is this the dry time?

Schooler: Yep, it’s the dry time of day, I should say yesterday at around three o’clock it would have been covered by water and then…

Miller: Then how deep would we be standing in water right now at high tide?

Schooler: It depends on the time of month, but yesterday it was 7.8 ft and so probably would be about a foot underwater. So we’d be walking through a foot of water here.

Miller: Okay, I’m glad we came now.

Schooler: Yeah, it’s better time to come.

Miller: What is this? There’s a sort of a white PVC pipe in front of us here, just sticking out of the ground?

Schooler: It’s actually just a marker. And so underground we have a number of tea bags arrayed around this that are tied to the marker and we put them out in June this year. So we buried them about three months ago, and now we’re going to dig them up and take them back and dry them and weigh them to see how much mass they’ve lost through decomposition over the past 90 days or so.

Schooler: Tea bags, we use two tea bags because they are standardized measure of decomposition. And so if we have 30 different reserves and all doing the same thing. And so if we use the same type of material, we can make generalizations across the whole system using the same tea material and we use tea in particular because it takes a little bit of time to decompose. We actually use two different types of tea and that gives us two different measures of decomposition.

Miller: And this is some kind of standardized scientific model, using tea bags?

Schooler: Yes, it is. And it’s a particular tea that comes from the UK. It’s a type of Lipton tea that we use, and everybody around the world who wants to do these sort of experiments uses the same tea, so not only can we compare it with our own, within our own system, but to anybody else who uses this type of material because we could use different plant material if we wanted to, but they all have different decomposition rates, so it’s hard to compare them unless you’re using the same material.

Miller: Why do you care about the rate of decomposition in this patch of marsh?

Schooler: Well, we’re interested in carbon storage or carbon sequestration. And we’re interested in how it changes in marshes over time. So normally marshes and wet areas and wetlands are really good places to store carbon because when things are covered with water, they decompose more slowly. And we want all that carbon that the plant material is sequestering in the plants, rather than just having it decompose and release that carbon into the atmosphere as carbon dioxide. We want to keep it in the soil and then under the marsh surface. And we’re trying to figure out how much marshes do that, high and low marshes and tidal systems. And also if that’s going to change under climate change with increasing temperatures and changes in water level.

Miller: So what do you do next? We’ve arrived at this marker that has the tea bags tied to it. What’s next?

Schooler: The next thing we do is we dig up the tea bags and so you might see each of these. There are three different sets of tea bags and I have a cord that’s attached to them. And so if we follow that cord down, we can see where it was put in last year. And we can sort of dig around here and pull it out. And we have a mesh, it’s actually just windscreen and then the tea bags are inside one on either side. You can’t really see them very well. But there’s a one teabag on either side of this, there’s some green tea and the Rooibos tea and it is…

Miller: I’m not gonna be drinking this…

Schooler: Probably not, but you never know …and each of these tea bags was pre-weighed, so it was weighed, dried and weighed in the laboratory last year or earlier this year, and so then we can compare it and see how much it’s lost. So we have our numbers here. We happen to know that this, in the low marsh, is number 100. There should be, yep, that’s it there. And so we can put all of these from this one into this one bag because they’re all marked with the color coding.

Miller: Colleen, am I right? That you’re an intern for the fall from Clackamas Community College?

Colleen Walker: Yes, I am.

Miller: Did you have any idea what kind of research you’ll be doing when you arrived here?

Walker: Yeah, I was actually also an intern at South Slough over the summer through a different program.

Miller: So did you put these tea bags in?

Miller: Is it cool to be coming back to take them out?

Walker: Yeah. Being able to see like full circle everything that’s happening and finish this project that we started earlier is pretty satisfying.

Schooler: You can see how wet the ground is there too – in the low marsh; high marsh, it’s not that wet. We’re kind of measuring also a difference in wetness as well, with these low and high marsh.

Miller: It seems like there’s so many variables here. There’s the tides that you mentioned, that this could be a foot and half underwater in 12 hours or something. There’s also saltwater or freshwater. I mean, how does all of this interact and affect decomposition?

Schooler: That’s the question. And that’s why we have this site here, but we also have four other sites up the estuary in different conditions. So there’s fresh water. There’s areas that are high marsh, drier and low marsh at each site. There’s some on islands, we have to kayak to get that, but we’re only doing a small fraction of it. Around the country, all these different reserves are also doing it. So they all have five sites and they all, there’s 30 reserves, we’re talking about 150 sites. So when we combine all that together, we have a much better idea of decomposition and how decomposition over time is going to occur even with climate change.

Miller: So, on some level, what you’re looking at here is how… on how climate change is affecting decomposition, which actually can then have its own actions on climate change. In terms of how much carbon is being sequestered or not. What about just broadly, how climate change is affecting ecosystems like this, warmer waters, more acidic waters, warmer air, but also perhaps more flooding. More extremes of rain and drought. I mean a lot of different…

Miller: …variables, but broadly, how is it affecting these increasingly unusual estuaries?

Schooler: That’s probably too big a question to answer directly. We’re also worried about ocean acidification, things like that affecting shellfish. So not only the marine environment, but also the terrestrial environment. We’re worried about things like lamprey, salmon, our anadromous species that go up...and is if things get drier, they won’t have as much of their range anymore, they won’t be able to live in those areas. So there’s all sorts of different implications of climate change. For this study in particular, we’re interested in temperature, because as temperature goes up, decomposition goes up. So we’re worried that climate change itself might release more carbon dioxide from these marshes. On the other hand, we have sea level rise. And so there’ll be more water on these environments, which will slow decomposition. And so more salt water as it goes up into the estuary further should also decrease decomposition. And so we have these different things that have different traits and we’re trying to figure out how they all interact in the future. And do we have to worry about a lot more carbon dioxide going into the atmosphere from these marshes as they decompose.

Miller: Is land like this, and this sort of marshy, in-between land, I mean, is it increasingly being lost to human development around the world? I mean, are we standing on a part of earth that is increasingly uncommon?

Schooler: Yes. In fact, I think some recent work has found that about 80% of this type of marsh has been lost throughout the Pacific Northwest and down into California. And so not so much now, maybe, because there’s more, we understand how important it is and we’re putting rules and regulations to stop it. So in the past a lot more was lost a lot more quickly. But we’re still having trouble preserving it because people want to build on these kind of lands, they see it right along the ocean and things like that.

Miller: So just fill it in somehow and then build on top of it is the idea.

Schooler: Yeah. And again, there’s lots of restrictions on that now, but there still are ways to build in wetlands and in estuary systems. We don’t do enough mitigation to try to stop that. Now, we’re actually trying to restore a lot of these places that we … if we can. Yesterday I was out kayaking and I saw hundreds, thousands, of these little fish all along the edges when the high tide comes up in these marshes. And so we know that these are very important places for fish like salmon, to get food from, because the water comes up, all these little critters all fall in the water and they’re all swimming around and the fish, it’s like a buffet basically for fish.

Miller: How long have you been working and walking around and studying this particular, this whole area?

Schooler: Well, in South Slough, I’ve been here for about four years, but I also was the Research Coordinator at Lake Superior Reserve for seven years before that.

Schooler: So it’s another reserve. And so there are some reserves in the Great Lakes as well. There are freshwater reserves.

Miller: Have you seen changes yourself in the course of your Marine Estuary Reserve that you attribute to climate change?

Schooler: I think so, we’re seeing changes in hydrology – so that the more water that comes on,  the more that has to come off too, and so high, higher tides and higher surface water changes how much water flows. So that’s one of the things that seems it’s happening, but not a lot. You don’t see a lot within a few years period, I mean, it’s a long time period. So all the stuff we’re doing now, we’re taking data over decades of periods of time to understand what’s happening.

Miller: My guess is that if a lot of people just took some wrong turns and ended up right here, they wouldn’t say this is beautiful, they might get slightly wet shoes and and just think of it as a kind of wet marsh with some channels, they could fall in if they weren’t paying attention Do you see beauty here?

Schooler: Oh, yeah. No, it’s these plants here, the things that they can grow in salt, is beautiful, I think.

Miller: What are these plants right here? They have almost like some of reddish…

Schooler: That’s called Pickleweed or Sarcocornia Perennans is the name of this one. It is even edible. You can eat it, it has a salty taste.

Miller: So let me see- what can I eat, this part?

Miller: Yeah, that’s salty and sour. Yeah, that’s good. It’s like a natural pickle.

Schooler: And there’s the stickalus picado, which is the grass in here. Again, they’re all salt tolerant because the water has salt on it when it comes in. There’s a great diversity of stuff as well... so not so much right here, but if you go up to the high marsh, you see tufted hair grass there and there can be 20 or 30 species per square meter in those. So a lot of plant species. And yeah, I guess it’s beautiful for the energy that goes into the system too. If you’re here for a while and you see the tides come and go and you watch the crabs running around through the channels or the fish that come in. I think it takes a little bit more to see the beauty. I think maybe because it takes it’s not something you get instantaneously. It’s something you have to appreciate over time. It’s one of the things the reserve is trying to do. We have a whole education program that is aimed at getting people excited about these sort of habitats that may have that. They may want the kind of pastoral landscape beauty, like where it’s a cut field of hay or something. But, no, this isn’t that. This is a natural system and it’s producing things and we should appreciate it.

Schooler: Yes, lots of people come and they appreciate the reserve. There’s easier ways to see it too. You can walk on trails, we have some overlooks where you can see a marsh called Hidden Marsh, which is really beautiful. So there are easier ways to get to these places as well. But I think it’s nice just to stand in it. Or if you can bring a chair you can just go and sit and wait for the tide to come up and see what happens. Or go kayaking is a great way to.

Miller: Do you do that?  Do you come and bring a chair, I mean, this is your work, but it’s also your pleasure or your solace?

Schooler: Yeah, I do. I sit, like yesterday, I was sitting in the marsh that I was collecting samples for DNA samples for lamprey, and I had…

Schooler: Environmental DNA. So where you can actually filter water to see what species are in that stream…

Miller: Based on their poop or you know…

Schooler: Just stuff that slips off of them. I mean it might be poop or it might be some skin material or something like that that’s come off of them.

Miller: So you’re doing that for lamprey and then you just sat in your chair and…

Schooler: In this case I was sitting in a kayak watching the fish. So the chair was mobile.

Miller: And there are birds here too I imagine.

Schooler: Yeah. I saw a brown pelican yesterday, for example, which we don’t get a lot of pelicans around here. But again in the water with the kayak you see all sorts of things, kingfishers, pelicans, egrets and blue herons, just all sorts of different you know… I scared up about, I don’t know, 1,000 or so ducks and geese in one of the little places I was sampling up in the estuary that no one ever goes to. So I was there and suddenly this tiny little beaver pond had just an amazing number of ducks and geese that are migrating down through. And they were all in this one little pond.

Miller: Are you going to all put more tea bags down or is this decomposition period over?

Schooler: This is the second year. So we did it last year. We tend to do it in the summer because that’s when the temperature is highest and you get the most effect of decomposition. Although we have question where we’re gonna go next, we may do this and do winter sampling. So we may do it for winter period. So it may not be the end. But we know we want to take this, we’ve got two years of data for the summer for all these different sites. We want to analyze it and see what we find.

Miller: Shon Schooler is the Lead Scientist for the South Slough Estuarine Research Reserve and Colleen Walker is a fall Intern there, we spoke yesterday. Tomorrow on the show, we’re going to take you inside a peer-run Drug Treatment Center in Coos Bay to hear. what addiction looks like on Oregon’s South Coast right now, but also what money from measure 110 could mean. If you want to miss any of our shows, you can listen on the NPR One App on Apple Podcasts or wherever you like to get your podcasts.

Our nightly rebroadcast is at eight pm. Thanks very much for tuning in to Think Out Loud on OPB and KLCC. I’m Dave Miller, we’ll be back tomorrow.

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