Webinar: Helping Coastal Wetlands Survive Climate Change

You.

I'm Heather Goldstone and I'm Chief communications officer at Woods Hole Research Center. We started this webinar series this spring in order to stay connected with and maybe even connect with some new folks through this virtual event format. When our in person events were no longer possible because of COVID we've continued them because we've really been enjoying it and we're really glad to have you here. In case you are relatively new to Woods Hole Research center, we are a relatively small organization of renowned scientists working based in many cases, in most cases in the community of Woods Hole in Massachusetts, but working with a global network of partners really to be able to better understand and also combat climate change. And when we say combat climate change, we mean both mitigating, trying to actually stop the causes of climate change, but also dealing with the impacts of, of climate change. And that's where we're going to focus a little bit more today on the idea of adaptation and resilience, and especially along our coastlines, talking about wetlands, salt marshes and their role in coastal resilience and the many dividends that preserving and restoring coastal wetlands can pay. And I think this is a particularly timely discussion given that we've just seen a powerful storm work its way right up the east coast of the United States and through some areas of prime wetlands. And of course, one of the things that wetlands do is to buffer storm surges and waves and protect adjacent communities from flooding. So we want to get to that discussion. But of course, for those of you who have been with us for past webinars, you will know that we try to do something that's a little akin to the, the looking around that you would do if you were entering a physical room for an in person event. Try to get to know who else is in the room. And right now we have about 100 people in the room, some folks still joining us, but of course, most of you can't see each other, which is one of the drawbacks of this virtual setting. But one of the wonderful things about these virtual events is that we're able to connect, both on our panels and in our audiences with people all over the world that we are not constrained by any particular geography. And so one thing we would love to know is where you are joining us from today. Tell us where you live and where you've hopped onto this webinar from. Getting a couple of responses right off the bat from the US Northeast and Canada, also seeing some people joining us from the west, the Midwest, the south, one or two folks from Europe. So, as has been the case with many of our webinars, much of our audience right here in our own backyard in the Northeast, but many people also joining us from around the U.S. and outside the U.S. let's see, we've got about 80% of our attendees have voted. So I will go ahead and end that poll and share the results with you. Now, of course, where you're from is only one way to get to know a person. And we're here today to talk about salt marshes and wetlands. We thought it would be fun to maybe get a sense of how familiar you are with salt marshes. We'd like to know, how often do you visit a salt marsh? And obviously, for those joining us from the middle of the country, this is probably a rare event to be visiting a salt marsh. But for those in the Northeast, it could be quite a common occurrence. And let's see, What I'm seeing here coming in in the results is that most of you are saying anywhere from daily to weekly to a few times a year. About a fifth of you say never visit a salt marsh. So we've got a range of flow familiarity with salt marshes, at least in the sense of being there in person and visiting one. And so I'm really glad to let you know that we're actually going to be able to kind of virtually visit a salt marsh today in our webinar. Not as much fun as actually boots in the mud, but as best we can do in this particular setting. And one last question for you along these lines, for those of you who have visited, perhaps do visit on a regular basis, a salt marsh. How old were you the first time you visited a salt marsh? And I left these very, very vague age ranges here, little kid, teenager and adult, just to get a sense, you know, when you think back on that first time that you visited a marsh, were you a little kid, really just, you know, out exploring, perhaps with an adult that you loved or knew? Were you a more independent teenager out exploring the world, or is this something that you really didn't get introduced to until you considered yourself to be an adult? And we've still got votes coming in, but the percentages aren't changing much. So I'm gonna go ahead and end this poll. And 55% saying a little kid the first time you visited a salt marsh? I have to say for myself, I was right on the cusp of little kid to teenager. The first time I remember visiting a salt marsh anyway, I was about 12 years old and doing a summer camp, and it was an experience that really literally changed my life and helped chart my career path going out as the teachers in that summer camp called it marsh mucking in the Chesapeake Bay. It was really a wonderful experience and I would say gained an appreciation even of the smell of marshes, which some might say is an acquired taste. But I have a feeling we have four people with us today on our panel, all of whom have acquired that taste for the smell of salt marsh. We're going to have a presentation from Woods Hole Research center senior scientist Linda Deegan, followed by a panel discussion. And we are so grateful to have folks from outside Woods Hole Research center colleagues from other organizations joining us for this conversation. So. So in addition to Linda, we have Hilary Sullivan, who's a research assistant at Woods Hole Research center, working with Linda, also simultaneously working on her PhD at Northeastern University. You will also hear later from Jack Oliver, who is a senior regulatory scientist with the U.S. environmental Protection Agency Office of Water, based in Washington, D.C. where he tells me it is hot and humid today. Feels hot and humid here on Cape Cod today, but I'm sure it's nothing compared to what's going on in D.C. and then last but certainly not least on our panel today, we also have Susan Adamovich, who is a land management research and demonstration biologist at the U.S. fish and Wildlife Service, who's going to bring in more of a perspective on coastal resilience and restoration. So we're really excited. We want to get this conversation started and make sure that we do have plenty of time for that conversation. As always, you can drop questions into the Q and A, preferably the Q and A, rather than the chat, just so that I'm looking mostly in one place for those. Feel free to start dropping questions in the Q and A as Linda is presenting. And we will then, after Linda's presentation, welcome our other panelists and join in a bit of discussion for the rest of the webinar. So without further ado, I will hand it over to to Linda Degan, senior scientist at Woods Hole Research Center. Linda, take it away.

Thank you. Heather, do you have my screen up there?

We do. We are seeing your presentation. I'm actually seeing your presentation with your notes next to it, though we seem to be seeing your other screen now.

How's that?

Perfect. And I have to say, I love that photo. I'm guessing you were in the little kid camp for the first time that you visited a salt marsh.

Yeah. Thank you. I'm really delighted here to talk to you about my work in coastal ecosystems. Heather said she took a camp Trip called marsh mucking for me when I was a kid, I liked magic. This is a picture of me when I was about 10 with a mess of speckled trout I caught in an Alabama estuary while fishing with my dad and my mom. And you know, I probably could have told you right about then that I was going to spend the rest of my life trying to study coastal ecosystems. I was just fascinated with fish and how they worked and where they went. And it wasn't really until I was much older and I took a course actually from George Woodwell, who founded the center, that I learned what I wanted to be, was an ecosystem scientist. And so delighted to be working here now on those kinds of issues. You know, I've had lots of opportunity in many places around the world, but I work in Alaska, I work in the Brazilian Amazon and keep coming back to coastal ecosystems. And it started just because I like them. I mean, this is a picture for those of you who haven't been there. This is an salt marsh on the north shore of Boston, basically up near the New Hampshire border. And I studied, actually was introduced to salt marshes by my undergraduate advisor at Northeastern University. He pointed me out, said if I wanted to study fish, that I should study a little fish called mummichog. And I was at the time a little disappointed because it's very small. You know, you can see it. This is a picture of the fish in a hand of someone superimposed on the large marsh there. But I think you'll see as I talk through this discussion today that this mummichog really, you see them everywhere in the marshes, skittering about from Florida to North Carolina, all the way up to Canada. They really play an outsized role in coastal ecosystems. And I think that you'll understand that they're an iconic fish of salt marshes and they have a really important role in coastal ecosystems. One of the reasons that I love marshes is again, they're the same reasons lots of people love salt marshes. They're beautiful and peaceful places for enjoying nature. They are one of the world's most productive ecosystems. And by that I mean there's a lot of energy moving through the system and supporting a wide diversity of fish and wildlife and people. So here, you see there's my favorite fish there in the beak of this bird in the food web. This is a picture here of one of my long term colleagues, Bruce Peterson and my niece Erin, enjoying some, reaping some of the benefits of that food web, those little tiny fish and works its way up to bigger fish. We all enjoy going out and catching. But marshes also play a lot of other ecosystem roles that are less obvious than just producing fish or shellfish. And one of the really big ones that we've come to understand is the importance of them being sort of from coastal storms by being a physical barrier between the that come with those storms. And mentioned, you know, we've just had an example of how well this works. The hurricane tropical storm Isaias came through, pounded a lot of areas, particularly down in North Carolina and South Carolina. But those people benefited by having this ecosystem on the edge and sea that can sort of take up some of that storm damage and protect those upland. But salt marshes are also, they're right on the edge of that land and river. And half of the population lives within that area of the coast. If you think of where you live and where most of the megacities of the world are, Boston, New York, London, Tokyo, Rio, they're all that coastal zone. We love living in the coastal zone. And that has had some challenges for resilience of these areas of the world. And what we really need to be doing now is thinking hard about we keep those populations in the coast from damaging the systems that they come there to enjoy. And so that's a lot of what I try and do is think about how, what are the impacts, what are the changes that are occurring, moderate those, how do we sort of take a step back. And although sometimes it does feel challenging, that there are also some hopeful signs that we're doing a better job than maybe in the past. So right now marshes are losing ground. We are losing marshes. Globally, they are shrinking. They are, they are falling apart. In the past, that used to be caused by fairly direct things. So on the left hand side of this slide, you can see here, this is just Boston harbor. And this green area was the upland area in Boston harbor in the 1600s. And these lighter green areas are areas like Back Bay that we filled. Those were salt marshes that we filled in order to create more cities and more city in town. And this happened all over the globe. Now we've come to understand that salt marshes play such important roles that we can't just fill them willingly More that that's not the most benefit that we can get out of this area on land or from our coastal wetlands. And so really globally, most dredging has stopped. Now there's some places, but mostly we've stopped this sort of direct disturbance. Now the problems are actually diffuse and that makes them really kind of harder to tackle. And the I want to talk to you about today are Excess nutrients in coastal water. So we call this eutrophication. And that has some big implications, we understand now, for salt marshes. Also, climate change. And climate change, again, is one of the biggest challenges in the next century. And in the coastal, it's really two fundamental things. One is that is rising, right? So the height of the ocean against the land is rising because of higher temperatures, melting polar ice, all of those things that I'm sure you guys know about. And coming with that is an increase in storminess, hurricanes. So we're seeing more storms. The prediction is that more and more hurricanes, more and more stronger storms on the coastal area. And I think that, you know, that if there's one thing I want to leave you with today, it's that the idea that we can, by combating some of the classic things that we've always worked on, excess nutrients in the coastal zone, that those two things are very synergistic and they together cause more damage one does alone. And I'm going to talk to you over the course of this presentation here, and then we have Jack and Susan and Hilary to also talk to you as well. You know, one of the. One of the things or one of the facts of life for salt marshes are simply close to areas with high nitrogen inputs to the coast. The map, a global map of where is the nitrogen. So this is all these different colors of gray to red that you see on this map globally. And these red areas are areas where there's really a high amount of nitrogen coming from land to the coastal ocean as a result of building cities, of high use of fertilizers for agriculture, septic outputs. And, you know, a lot of ways that we use land that through the water that comes from the land to the sea, delivers nitrogen to the coast. All the little dots are areas where there are salt marshes, salt marshes that we depend on for that buffer and for that production of fish and shellfish. So you can see they really are clustered here in the temperate zone. And of course, people are clustered in the temperate zone. So we're seeing a lot of impacts in the temperate zone of a lot of delivery of nitrogen to marshes. Well, when I was an undergraduate, we had this idea. We thought about salt marshes as actually being able to mitigate that nitrogen loading. So we thought of salt marshes as the great nitrogen sponge. All this nitrogen would come from land washed into coastal waters. And the nitrogen, see this great vast field of grass, the nitrogen would be taken up and those plants would grow and they'd fuel a food web that ultimately lead to fish that we liked. And as part of that, the microbes would also process that nitrogen. And they were, the microbes were kind of a release valve. They would take the nitrogen out of the water, process a little organic matter, and kick that nitrogen off into the atmosphere as N2 gas. In this is called denitrification and decomposition. And all of those are processes that we thought salt marshes could just buffer the uplands from storms, but they would buffer the coastal ocean from nitrogen.

Right.

So they were playing this really critical role of buffering the upland from storms, food webs producing a lot of fish, and then also buffering the ocean, which is really impacted by nitrogen by stripping water before it went out into the ocean and could affect say eelgrass or systems. Well, a few decades ago, some colleagues of mine, we sat around and we thought about this and we thought, well, that's what we think happens. Nobody really tested this idea. We did a lot of little tiny experiments on 1 meter squared and all stuff looked good. But really, you know, if you think about it, that global map that I showed you says that we are just adding tons and tons of the coast without really understanding what the impacts in salt marshes were. And so as a result, we developed what we call the tide project. So we're looking at tidal marshes and we went into a system north of Boston called Plum island and we developed this large scale ecosystem experiment. So in the upper left hand corner of this slide you can see we had whole marsh ecosystem reference sites in blue and then we had sites that we fertilized here in red. And what we did was to increase the nitrogen in those systems to 10 times level. Now 10 times seems like, you know, it's some nitrogen, but it's not a hundred. We did however, you know, we increased by to a concentration of 1 milligram per liter. And again, doesn't sound like much. And indeed that is 1/10 of the drinking water standard for humans. So we really thought, well, maybe it won't have much impact, but this is a very realistic loading. It's a realistic loading in that it represents about 1,000 houses in the watershed to area. And the thing I think that me really quite a bit was how hard it was to explain. To do this, we needed two semi trailer trucks stacked high fertilizer every year. And we had to haul them out bag by bag by bag, 50 bags a week or 50 bags every three days, put them in a system that added it with a computer program to result in having this high nitrogen level. I mean, we do this every day without thinking about it by our fertilizer runoff, by our septic systems, by our agricultural runoff. But when you look at it stacked up in terms of bags of fertilizer, it really impacts you how much we're adding to the coastal system. Very large, very experiment that's been out for almost 17 years. And I can't possibly talk to you about all of the things, so I want to just focus on one really pretty critical. First of all, you can imagine if you're a gardener, you know, a little nitrogen, you add a little fertilizer, and your plants grow better, right? And so that was our. The. We'd add this nitrogen, the plants would go better, grow a little bit better, and those plants would feed the food web. And so it could be a plus, right? You're adding nitrogen, increasing plant growth that turns around and increases fish growth. So we tested that idea by measuring how much the plants we found two print impacts. First of all, it turns out that we increased the above ground, the visible part that you can see, that grassy green stuff, the salt marsh, this Spartina alterniflora plant, what it's called by actually very little, less than 15%. Every, you know, every year it was a little bit. We got slightly taller plants. The leaves had a little bit more biomass to them. They had more nitrogen in them. That was an expected thing. They had fewer stems competing with each other for light. The thing we didn't anticipate was that after the plants had grown for a while, they got too tall for their stems and they fell over into the marsh. So they stopped growing. And I think that's part of why we didn't see this huge response. And if any of you are gardeners and you've grown corn, you know, this is a classic response of grass that gets too much too tall. Corn grows too tall, outgrows its stems, the wind blows and they fall over, and they stop being productive. The other thing that happened, which was a little more surprising to us, roots that these plants were putting into the.

Soil.

Decreased by almost 40%. So we had 40% roots in the ground, less total biomass in the ground. So you can see this picture on the screen. Here's a reference one. You can see white bits that are roots here. And over here is a root core from a site that was fertilized. Far fewer roots. Well, this turns out to be important because those roots stabilize this creek bank right here. This is low tide at Plum island, but when the water comes rushing up, the tide covers up this marsh grass, and there's very strong currents there. And those roots help hold that bank together and help it resist storms, hurricane surges and just regular tidal surges. The other thing that happened was again we stimulated those microbes to denitrification, but that meant they were also decomposing organic matter. So all this brown soil that you see here has lots of organic matter. And you can see again in this core that it's sort of all soft and mushy looking compared to this sort of solid looking reference one. So those things together, the fact that we didn't stimulate a lot of the above ground, did decrease the below ground that was stabilizing those edges of the, of the marsh. And we increased the microbial decomposition rate to make the soil sort of easier to move in. Storms all led to a change. These tiny, tiny changes that didn't seem much led to a big change in that ecosystem. Now the interesting thing is it took almost five years for us to understand in the system why these small changes matter. So this is a diagram here of a sort of reference salt marsh. We see this vast plateau of grass, that strong tall stuff on the edges with a creek here. Here's what happened after nutrient. So the bottom is a photograph here showing you that same kind of creek profile on the right hand side here you can see what happened. With high nutrients enrichments, the creek bank started collapsing under its own weight, got winnowed away by storms, it started slumping into the. But this only happened after about five years. Wasn't something that we anticipated. Really stumbled onto this because we realized that, you know, our stories at the end of the day that we tell each other as we came back hot and muddy from the marsh were changing. We talk more about getting stuck in mud. And me, I thought it was just that I was getting old, right? It's harder to move around. The graduate students and the undergraduate students were telling me the same. They went to these fertilized nutrient enriched creeks. It was muddy and soggy and hard to move around. And the picture here that you see at the bottom on the right hand side, that's me in the marsh. And you can see one of these slumps where been vibrant green grass is now just turning into mud. And this is like changing the whole way that ecosystem works. And this is critically important to a salt marsh. That interface between the water and the marsh itself moderates a lot of the things that we want marshes to do for us in terms of removing nutrients and stable banks and protecting shorelines. And the thing we published that paper in Nature and I so much feedback from people like you who have been going to marshes over your lifetimes and you say, I go to my favorite marsh changing, it's falling apart. And this was reported to us time and time again. And in particular the, the Westport Fishermen's Association. Westport is an estuary here on the south part of Massachusetts reported chunks of marsh caving in and marshes converting to mud that were very reminiscent of our Tide project results. So to show that what we saw in our environment was happening by generalized coastal nutrient, we went out there and made a lot of the same kind of measurements that we did in the Tide experiment. So this is Molly Weiner here taking some of those cores that I talked to you about that allowed us to see that above ground, below ground differences saw was that what we saw in the TYE experiment was playing out writ large in this very large estuary area where in that estuary that high had higher nitrogen is where we were measuring a lot higher rates of marsh loss. So plants converting to mudflat. When we took a look at the roots of galley, fewer roots in those areas that had high marsh losses. And as a matter of fact, areas with the most marsh loss in Westport, this large estuary on the south Massachusetts had below ground biomass levels in about the same range as our tide experiments. So this really told wasn't just our experiment, but this was something that could easily be happening coast wide. Well, so I told you I like to do fish. So let's get back to the fish. Why matter to the fish? I mean, so little marsh edge change the sort of structure of it. How does that change the food webs and how does that change the response of what I call the marsh canary? This, this is probably the largest mummichog you're ever going to see in your entire life. This is huge for a mummichog, but it's very, it's. This is a very good picture of it. And this is the food web down the bottom. You know, all the little bits of creatures that lead up to making this fish. And one of the things about this fish that you're really is that this fish, the mummichog, feeds even bigger fish with the mummichog. Well, it turns out that this eutrophication, this artificial eutrophication, this nutrient enrichment caused changes in food webs and in fish behavior, which led to a loss of fish in these ecosystems. But it was lagged a little bit behind after the change. So you can see down here at the bottom, there's a graph that shows you when we started the experiment, years one and two, the reference sites and the, and the fertilized sites were at about the same production. We got the same number of fish per meter squared, about 5 grams of fish per meter squared. As a matter of fact, a little bit of nutrients in a couple started increasing the number of fish that we had until the marsh edge started falling apart in that, about year five. So in year five we kind of peaked and we thought, okay, we're doing good. The marsh edge looks a little crappy, but you know, the fish are doing okay. We kept studying this for years and then we saw that the fish biomass just dropped off precipitously. So now after a decade, we have 1/10, 1/10 the number of fish in those nutrient enriched creeks than we had in the ref, than we have in the reference creeks. And we think that's because they've changed their behavior. So now in, instead of going up onto the marsh platform and having that huge vast area of marsh to, for food from, they're hanging tight in those clumps because in, because in these here are predators. And it also takes them 3, 4, 10 times as long to get up to this area. So by the time they get to this area, they've run out of tide and they have to just turn around and come back. So that change, that subtle change in the amount of below ground, the 15% change in above ground, combined with the microbes, with a little slumping, a little marsh edge law ecosystem to have big changes in that small fish. And as I said, little fish feed bigger fish. So one of the things that mummy for us and ecosystems, that they migrate out of that marsh into this big open bay area and they feed striped bass and bluefish and other larger fish. So we've done some calculations that show that a healthy marsh produces grams of mummichog per year. And in plum island that's 2,000 kilograms of mummichogs. And that food, those mummichogs can feed 4,4500 legal striped bass per year. That's a lot of striped bass production. So that if you start cutting that 5 grams of mummichogs down to 1/5 of a gram, you're going to have 44, 50 or 45 instead of 4,000 striped bass. So these little changes in the marsh add up over time, over decades to affect the food web. And that has effects on the larger ecosystem, the larger coastal ecosystem. So yes, marshes are the great nitrogen sponge, but not without limits. And when we pass by those limits, we stimulate nitrogen uptake by plants a little bit in the food web. But changes in those creek bank edges and access to this large, vast expanse gets cut off. And so we're not fueling that food web anymore as much as we were in the past. And also by stimulating decomposition, we take marshes from being a plant that takes nitrogen, takes the atmosphere to an ecosystem that's actually putting CO2 back into the atmosphere. And that's not what we want to be doing here. Marshes should be what we call blue carbon sinks. They should be systems that take CO2 out of the atmosphere and help buffer climate change and the CO2 that humans are putting into the system. But our nitrogen loading is making that function not happen anymore. So you've heard of the butterfly effect and the domino effect. I think what we're seeing in salt marshes is a bit of the butterfly effect and also the domino effect, little changes over a long period measured carefully really have big implications for coastal ecosystems. So when I started studying Marshes, there were 4 million people in the world when I was an undergraduate, 7 million when we started the Tide project. And now there's about 8 billion, soon to be about 8 billion in the world. So how can we achieve a world where nature owned people thrive? I think it can be done if we're careful, if we think about it, if we exhibit some restraint. And I also think we are equal to the challenge. And I really take heart in the story of Boston harbor, which in 1982 was dubbed the harbor of Shame. And for those of you old enough to vote in 1982, you might realize that this the presidential election, but now in the, in the 2015, Boston harbor beaches have been cleaned up, we've taken care of the sewage inputs, we've put in some treatment plants, and Boston harbor beaches they say are more clean than Waikiki in Hawaii. And I say that's a testable hypothesis and I'm willing to go to Waikiki and test this. But until then, this really gives me faith that some of those big large that we need to tackle from this widespread pollution, which we haven't completely solved by any means, but also climate change are something that we can really get a handle on and do something about if we're committed. So what can you do? Just keep paying attention like you do, keep pushing on your politicians by your, by your state and federal legislatures. I mean, even if some of these things are a big hoax, just create a better world. And that's not for nothing. We can do things to cause energy independence, preserve rainforest, have green mobile cities, and you can do little things in your own home, like if you're fertilizing your lawn so you have a bright green lawn. You don't need to do that. Live with a little bit less green in your lawn and also a little bit less green in your coastal ocean areas and you'll have more fish and a better place to live. Thank you. Great.

Thank you so much, Linda. Really terrific and really shocking, I think you said, even for you as one of the scientists out there in the marshes, to see the impacts and the extent of the impacts that those nutrients had on the actual structure of the marsh. And certainly I think pretty eye opening to see that right there on the screen. Now I'm going to invite the rest of our panelists to start their video and their microphones and join us for a bit of a brief broader discussion about this. And Jacques, I think I'll start with you from your perspective, working in the EPA Office of Water, looking at water quality regulations and the impacts that they can have and seeing how the work that Linda is describing really kind of takes us into a whole new realm of thinking about the impacts of water quality, from just thinking about the water alone to suddenly what's in that water is affecting the physical structure of these marshes. Can you just talk a little bit about your perspective on those connections and what that elicits for you?

Yeah, sure, Heather, and thank you for inviting me and it's a pleasure to join your audience and and fellow panelists. My day to day work, it's implementing a law most people have heard of, the Clean Water Act. And for me, the most important words of the Clean Water act are the first 20 words. And it goes something like the objective of this act is to restore and maintain the physical, chemical and biological integrity of the nation's waters. And I work in water quality and I work on specific pollutants, nitrogen, phosphorus that Linda discussed and what I've observed through the course of my career in working with state CO regulators, including folks at Massachusetts DEP and other New England water pollution control agencies, that nutrient pollution is really good at degrading and stressing these the things that bind physical, chemical and biological integrity of places like salt marshes. Sometimes, you know, the effects of nutrient pollution are really easy to see. And it becomes, I guess a little gets a little easier to draw a line and say, okay, we don't want any more than this much nitrogen and phosphorus. If you see a big algal bloom, you know, that's obvious. Sometimes it takes a long time to see those changes. Like in the Chesapeake Bay, you know, over the course of 40, 50 years, people have seen the decline in water clarity because of long term nutrient pollution coming into the Chesapeake Bay. And sometimes you have to, sometimes it takes a long time to see these changes and you have to look very closely to detect them. And I think that's what, that's the story that I hear from Linda's work is you look at a marsh and you see this beautiful green space. But unless you look very closely over a long period of time, five years in this case, you might not detect those changes. And so I think you have to sort of open your mind to think about all those things, the chemical and physical and biological integrity and how pollution and stress can degrade them.

Thank you, Jack. I'm going to ask Hilary Sullivan to jump in here. As I said, a research assistant working with Linda on the Tide Press project for several years and before that spent time working in marshes in southern Louisiana. So some different on the ground perspectives. And Hilary, you're actually joining us from Plum island today, right. We can see a little bit of the marsh in the background. Maybe you could show us a little bit more of the marsh. We can actually get a little bit of that on the ground view. And I was going to say there's some boats there. We can see human activity. And of course, where you're sitting right now, very close to the marsh. So kind of seeing that human marsh interface and the potential for impacts that we're really talking about, but also I guess seeing the potential for benefits. I'm wondering, Hilary, if you could just give us also, and Linda hinted at this in her presentation, a little bit of the experience of doing this work and seeing the changes firsthand over the course of several years. Just going out there and really witnessing this.

Yeah, thanks. So as you mentioned, I got my start in salt marshes working down in Louisiana in a very similar ecosystem, but also different in a lot of ways. And coming up to Massachusetts, I was excited to get a different experience, but soon found out and learned that a lot of the drivers of marsh loss that we were studying in Louisiana, so excess nutrient loading, eutrophication, sea level rise, are actually what's affecting these marshes up here. And so, you know, I was really excited to join a project like the Tide Project, which is studying kind of this ecosystem scale effects of eutrophication in one localized area. But to be able to study that and understand this broader scale implications for all marshes along either the Atlantic coast or the Gulf coast is a really, really unique thing to be a part of. And so just a little bit of my day to day, what it's like working in the marsh. I'm a biogeochemist by trade, so I look at understanding what and how much nutrients are coming into the marsh and where they go and how much they buffer it before reaching the open ocean. But I'm also get to be a part of some of the other field collections. We study the plants, as Linda mentioned, we study the fish, the invertebrates. And so what's really unique about my position and this project is that by combining all of these different various factors, we get this, we can scale up our understanding of how eutrophication and sea level rise and human interactions are affecting the entire marsh ecosystem. And what's really cool is the science that we do and the data that we collect and analyze can help inform policy. So stuff that Jack does or mining all of of these different various factors, we get this, we can scale up our understanding of how eutrophication and sea level rise and human interactions are affecting the entire marsh ecosystem. And what's really cool is the science that we do and the data that we collect and analyze can help inform policy. So stuff that Jack does or management strategies that sue does.

So, Susan, I'll jump to you now. You know, one thing in all of this, we've heard from Linda about the impacts and I wonder what opportunities you see for actually creating more resilience and ensuring that we do have healthy marshes and strong marshes because of all of the benefits that they produce.

Thanks, Heather. As you know, the Fish and Wildlife Service manages tens of thousands of salt marsh acres along the east coast at its National Wildlife Refuges. And we're very interested. We're actually compelled to maintain the biological integrity, diversity and environmental health of these salt marshes by Congress. And of course we're very concerned about the nutrient inputs. We have also been seeing these slumping impacts on salt marshes in southern Maine and other locations that I've traveled up and down the east coast where you would think there's, you know, there's no big housing development, we should be kind of pristine in southern Maine. And yet, as Linda said, it doesn't take much nutrients to, to cause some of these effects. And so I'm actually charged with trying to develop innovative salt marsh restoration techniques and work with research scientists like Linda and her colleagues to understand the ecosystem processes. So we honestly don't have a series of management efforts right now to tackle this nutrient issue outside of the large scale watershed processes that we've talked about. Building sewer systems, having folks understand the effects that how they manage their lawns at home can actually have a big effect on downstream ecosystems from their freshwater stream all the way down to the coast. So because the source of nutrients comes from a wide variety of small inputs, we have to sort of focus on those for our management efforts.

That sounds like a real challenge. I want to actually jump back to an image that Linda showed in her presentation. There was a, Linda, your map with all of the black dots representing salt marshes around the world and of course, then centers of population and potential for impact. But what struck me most about that map and Susan, and you, Linda, might both have some insights here is how relatively few black dots there were along the east coast of the United States compared to places like Europe or Australia where they were just completely covered in those. Those dots. Is that natural or is that human impacts?

It's more related to how they mapped it. So those points are not proportional to the size of a salt marsh. It's just a salt marsh exists in this area. So for instance, a salt marsh that was say 10 acres might have one point and a salt marsh that had 100 acres. And so a lot of the salt marshes.

Your audio cut out right there with those key last couple of words.

Sorry. So a dot might be a salt marsh that's. Or it might be a Salt Marsh that's 100 acres in New England. In England, most of the salt marshes are small between jagged coasts. So they get lots of little dots along our coast. Most of the marshes are big. So one dot equals more acres of salt marsh. So it's not. They have done. I mean, they've had a couple more centuries to fill salt marshes in England. There's another reason those salt marshes are kind of really small. But we did our fair share here too.

Yes.

So we've got some great question questions in the Q and A, and one of them is a really big one that we haven't really addressed yet. And we've been talking about these different kind of converging impacts and forces in terms of marsh health. But one person asked, how badly has warming due to climate change hurt the marshes? So is that also an impact? Because you mentioned obviously that they can't absorb carbon dioxide and be as strong a buffer against climate change when they're impaired. But what about climate change impacts on marshes?

Shall I tackle that one?

Go for it. And then I would love to also hear some of our other panelists thoughts on that as well.

So climate warming is an interesting multiplier effect. So the warming actually stimulates higher rates of microbial decomposition. So again, we're kicking more CO2 into the atmosphere. And it also can limit salt marsh growth because if it gets too hot, the plants respire more and they don't grow as much. It's an amplifier of a lot of the things that I talked about make it even tougher on salt marshes to be resilient in the face of, of climate change.

So Jack and Susan, kind of piggybacking off of that. How do you, when you're looking at a system like a salt marsh that's facing nutrient pollution and warming impacts and, you know, maybe other human physical impacts and other possible pollution, how do you regulate to take into account all of those different impacts? And Susan, how do you manage to take into account account all of those different impacts?

Yeah, great question. On regulating a global phenomenon. We're seeing many impacts from climate change. We see large variations in not only temperature, but precipitation, and precipitation can be stressor as well on aquatic ecosystems. Take for example, large amounts of water, large volumes of water, all rushing into a very small space habitat like a marsh or a small stream all at once. Right. And so you're having physical degradation, not so much chemical degradation, but physical degradation. But to your question about temperature and, and warming, you know, there are, I would say that there isn't an explicit approach to regulating temperature through the Clean Water act indirectly, perhaps through other environmental statutes like the Clean Air Act.

Right.

So regulating carbon dioxide emissions. But the way the Clean Water act is oriented, it's really designed to identify, designed to protect particular uses. So we think of them as in shorthand, fishable and swimming. And to the extent that pollutants interact with other factors like temperature to degrade what is a water body that is fishable or swimmable, we do the best we can with the science that we have to take into account those synergistic effects of temperature and nutrient pollution, as well as other stressors.

Susan, to you, in thinking kind of about the, you know, actually out in the marsh and management of these areas, how do you try to take into account all of these different conversions factors?

Heather, I'm hoping I'm sharing the screen with a couple of slides, a little illustration down at the bottom. Are you seeing that?

Yes, you are. That's great.

So this is a salt marsh in southern Maine in the town of Wells. And the picture on the left shows a type of water control structure that was installed in the marsh in the early to mid-1800s, kind of like a culvert at the bottom of a dike that you can see in the illustration below. But over the course of, you know, 150 years or so. The dikes aren't nearly as large as that anymore. And you can see my 6 foot tall colleague for scale. And the bright green area is the remnant of one of those dikes. So to get back to your question, we look marshes in a holistic perspective. Not only what's going on today, but the alterations that have occurred on them in the past. Because these alterations in conjunction with sea level rise and climate change are causing our marshes to change very rapidly. Linda spoke to the nutrient changes affecting the tidal creeks here. We're seeing these prior farming alterations as partly being responsible for the creation of these large water bodies in the middle of the salt marsh where there should have been that vast acreage of grass. And again, to get back to your.

Question.

What we're doing is developing innovative restoration techniques. Linda's familiar with the use of runnels or really shallow channels to help drain the water off the salt marsh surface to allow the grasses to grow again. And in places where there's a lot of ditches, either from salt hay practices or mosquito ditching, we're using something called D remediation where we use the salt hay harvested from the marsh surface to help heal the ditch from the bottom up. So again, we look at the salt marsh holistically, both its current stressors and the historic stressors and how they're impacting and affect, interacting with climate change, sea level rise and in global warming. Your questioner I think mentioned increased warming. And one thing that we've noticed, particularly in the last 15 years that I've been working in southern Maine, is really big swings in precipitation cycles. So we have now these periods of drought during the summer that we didn't used to have. So we may have a wet spring like we did this year, but then we entered, you know, six week period of drought where the marshes are extra stressed because of the salt content and the grasses don't grow as vigorously. And then we get hit by maybe a thunderstorm, maybe the thunderstorm doesn't come, maybe we get a tropical storm. Oh, we got maybe half an inch of rain here from this last tropical storm. So it's really hit and miss with precipitation. And that's a result of the global climate change.

So I want to Susan and Linda, the techniques, Linda, that you use in your research, this idea of actually a marsh being an experimental area where you're actually inducing, you're causing effects with nutrients out in a soil marsh in order to learn what happens. And then Susan, these techniques you're talking about where you're physically getting into a marsh and yes, it's facing impacts and it's been impaired in some way previously. But again, you're kind of getting in there and physically reworking it. In both cases, I could see people kind of responding to that and going, oh, is that really what we should be doing? Should we really be causing more impacts and order to learn things or potentially causing different impacts by getting in there and reworking the marsh? So I would love to hear from both of you. And we've really only got a few minutes left here in our webinar, but a little bit of just how you think about the cost benefit of these kinds of activities in terms of the impacts and the threats that are facing marshes right now.

Yeah. So we actually, Hilary and I have just embarked with some people on trying to evaluate the rentals that people want to use to make sure that we are doing something. There are people out there just doing them because they think they'll be useful on a research project to set up similar long term evaluations, environmental evaluations of their costs and benefits. In terms of how do you think about manipulating us? I think of it in terms of manipulating a very small part of a large environment to try and help us solve a huge problem. Right. So we manipulated maybe a total of 30 acres of marsh max in our long term experiment. And we are adding nitrogen to hundreds, thousands of miles of coastline. So a 200 meter long marsh we simulated along thousands of kilometers of salt marsh. But now we know we have the ability to say, hey, what we're doing coastally is not benefiting salt marshes and it's not doing everything we thought it should do. And indeed it's not beneficial in some ways. And so that's really caused people to regulators like Jack to say, whoa, let's take a step back here, Think about what those nutrient levels are. Salt marshes can help a little bit, but if we overwhelm salt marshes, man, we're just doing too much, too much. So I look at it in terms of manipulating a small bit of marsh to do something for the greater good. They usually try and do it, you know, with the runnels. We're trying to take an area that has known stresses and see if we can't fix those stresses.

Right.

We just have to make sure that the way we're doing it is helpful, not hurtful. And that's what we're trying to do in the experiment.

Susan, would you like to jump in there?

Yeah.

Just real briefly. My position is sort of unique in fish and wildlife Service, where my job is to develop these techniques. And believe me, I'm as nervous as anybody else about messing up a nice marsh. And so we start very small, very simply, to do a proof of concept. Does our idea even work? And then we expand it to a pilot project over, you know, square feet, rather than just a tiny little plot. And then we scale up like a recent project down at Parker river, where Linda does work in that system, the great marsh system, where we're now working over several acres. So we go very carefully. And these new techniques are more like arthroscopic surgery. You know, you think about that in knee surgery these days, they just make two little incisions rather than those big jagged scars that some of our senior citizens have with the early knee replacements. So we're really just being precise. And also, it's kind of hard to realize this, but most of our salt marshes have already been altered by farming or some other human impact. And so most of my job is trying to figure out how to undo what people have already done in the least disturbing way possible so that we regain those natural ecosystem processes that promote a healthy salt marsh in the first place.

And Jack, I would. We are one minute, maybe just over time. So I hope you will all indulge us in just a couple of more minutes here. I'd like to hear from Jack and Hilary before we wrap up, but kind of I would love to get your perspective on the importance of these kinds of experiments and these long term experiments in informing the regulatory sphere and also just, just kind of your national perspective on where we're headed. Do you feel like in terms of salt marshes, we're headed in a good direction at this point?

Yeah, I wish I had the kinds of experiences that Linda had and Hilary and Susan had, have had over the course of their careers to be able to be able to speak at those scales. I'll tell you what I know from other systems that I work on, other freshwater systems and coastal systems, estuarine systems, human population growth is on the rise. We have to feed human populations, and we do that primarily through fertilizing our watersheds, growing food, growing animals. And that inevitably has an impact. We also, you know, I think are, you know, we're definitely contributing to the changing climate and that's adding stressors as well. I think we have the capabilities, we have the ingenuity. I think it just, it's a matter of having the will and having the right tools, because there's some tools, regulatory tools, that just aren't sufficient to do the Job. I think the worst, I think we have, we have a lesson from the, from the Florida Everglades. And if you ever want to learn about what, what really got the Everglades in trouble, read Michael Grunwald's book, the Swamp. It's a terrific book. Right now, EPA in the state of Florida is spending a lot of money and they're creating constructed wetlands to remove phosphorous. But it's really not a story about phosphorus. It's really a story about 150 years of change, cultural change, physical landscape change, political change in Florida and South Florida that has led to the situation that we're seeing in the Everglades and why it's been so dire. But as I said, there's ingenuity, there's innovation, and there's hope for places like the Everglades. So I do think that there is hope, but we have our work cut out for us.

And Hilary, for the last word to you, I would love to get your perspective on the importance of the kind of long term experimental work that's going on in the TIDE project. And you kind of, kind of at the early end of your career and looking forward prospects for what we might learn and where we might be headed with this kind of research.

Yeah, so I touched on this a little bit earlier, but I think the importance of these long term ecosystem level experiments is that like Linda mentioned, these processes take time and sometimes they're also invisible to just the eye. Right. You can look out and see a beautiful salt marsh and think that it's healthy and fine, but really there's underlying mechanisms and drivers that are causing it to fall apart or making it more susceptible to loss. And so, you know, I think what for me, going forward and for the future of salt marshes, I think it's great that we have these manipulation experiments and these experiments where we're trying remediation and restoration strategies. But you know, what I don't think was mentioned is that TIDE is now in this recovery phase where we're still studying all the same components and we stopped fertilizing. And so now we're four years out and we're trying to understand if we are able to implement these remediation strategies or policies to limit nitrogen discharged to the marsh. Do we have irreversible damage or are these marshes able to recover and kind of resisting themselves to what they were or do they become a new normal? So that's, I think, where the hope is going for the future.

I think that's a terrific note to end on And I want to thank all of you. Hilary, for joining us from the field with all of the chat challenges entailed. Susan Adamovich and Jack Oliver joining us in the midst of your busy schedules. I know. And Linda, thank you so much for leading us today. And thank you to all of you who joined us. I know a few people had to jump off a little early. Thank you for staying the course and an extra few minutes in your busy days. We appreciate it so much. And we hope to see you back here at a future Woods Hole Research center webinar in a couple of weeks. Thank you all so much.