November 6, 2023 • 59 mins
Host Jeff Berckes kicks-off season two by discussing the role of nutrients in water quality. He is joined by professors Jamie Vaudrey and Jim Cotner to speak about phosphorus and nitrogen – two common nutrients found in freshwater and coastal ecosystems. They explore what these nutrients are, where they come from, and how they impact water quality.
About our guests:
Jamie Vaudrey is an assistant research professor with the Department of Marine Sciences at the University of Connecticut. She also serves as the research coordinator for NOAA’s Connecticut National Estuarine Research Reserve. Vaudrey is involved with EPA’s National Estuary Program, serving on Narraganset Bay’s science advisory committee and the Long Island Sound Study’s science and technical advisory committee. She received a Bachelors in biology with a minor in philosophy from Wellesley College, and completed her Ph.D. in oceanography at the University of Connecticut.
James (Jim) Cotner is a professor of ecology, evolution and behavior at the University of Minnesota. He has studied freshwater and marine ecosystems for more than 30 years, primarily focused on heterotrophic bacteria and ecological stoichiometry. Cotner holds a Ph.D. from the University of Michigan.
Follow the @cleanwaterpod on X (formerly known as Twitter) to keep up with the latest podcast news!
Learn more about NEIWPCC at neiwpcc.org.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Jeff Berckes (00:22):
Welcome to Season Two of the clean water pod, the show about the challenges and successes in restoring and protecting water quality. My name is Jeff Berckes, and I'm talking to dedicated professionals across the country to build an understanding of how policy and science work together to meet the goals of the Clean Water Act for fishable, swimmable and drinkable water quality in our nation's waters. We've got to change this year's show is Sarah Schwartz is on assignment. And we'll be joined by another EPA friend, Teagan Rostock. Teagan, welcome to the Clean Water Pod.
Teagan R, EPA (00:54):
Thank you, Jeff, for having me.
Jeff Berckes (00:56):
Well, we're really excited. And like we ask all of our guests, we want to know a little bit about you. So where did you grow up? Where do you go to school? And how did you get into water quality.
Teagan R, EPA (01:07):
I grew up in South Florida. And I was lucky enough to live right next to the Loxahatchee River, which is a really beautiful river surrounded by mangroves. It's filled with manatees and alligators, and all kinds of beautiful birds and other wildlife. And because of that, I really became passionate about water quality. And I went to school at University of Florida, and got my degree in natural resource management. And then I went on to Duke and got a degree in environmental management. So I have my master's degree.
Jeff Berckes (01:44):
So you right away thought, this is for me water quality. So from a young age, this is what you wanted to do. You you had the direct course through college, and then you found yourself with the Environmental Protection Agency.
Teagan R, EPA (01:57):
Yep, never changed my mind, I always wanted to do this.
Jeff Berckes (02:02):
So you are the rarity, because I gotta tell you, although in water quality, we find this a lot. There's a lot of passion early on that drives people to this career. So not unique in that. But overall, that's not necessarily the most common path for people to know exactly what they want to do. So there is something bonding about that water quality element. So this year, we're going to be focusing on nutrients and water quality, we're gonna be focusing all around the country on different success stories, people that are working on different nutrients and showing some successes and cleaning up some of our nation's waters. And we've got some great guests to kick that off. But I want to ask you, the EPA expert here to define the term eutrophic for us.
Teagan R, EPA (02:47):
Yeah. So eutrophication describes the buildup of excess nutrients such as nitrogen and phosphorus and a body of water. And in this podcast, you will hear a lot about nitrogen and phosphorus.
Jeff Berckes (03:00):
Yeah, absolutely. Right. So you know what, what I find interesting about eutrophication and this idea of eutrophic conditions and waters is that it comes down to these things called nutrients, which, you know, we want they're, they're desirable, nutrients are good, but if you have too many nutrients and water, you can start to get some issues. And so, to be able to help us understand that a little better, I interviewed two professors. And I want to know before we get into the interviews, did you have a favorite professor at the University of Florida?
Teagan R, EPA (03:32):
I had a few favorites. I don't think I could choose one.
Jeff Berckes (03:36):
Oh, that's good.
Teagan R, EPA (03:37):
Really great professors. Yeah,
Jeff Berckes (03:39):
well, I don't know that I have a favorite professor. But I remember I had a professor that went by Ace. His last name was Ventulo. So very close to Ace Ventura, Ace Ventulo. And he wore a lot of Hawaiian shirts, a very common ecologist kind of thing to do. Again, not sure if I remember him as my favorite, but certainly an interesting character. These two people that I interviewed for this podcast, I think, are probably a lot of people's favorite professors. The first professor that you're going to hear from is Jamie Vaudrey. She is an expert on nitrogen, and a professor at the University of Connecticut. And then about halfway through the episode, we'll switch over to my interview with Jim Cotner is an expert on phosphorus and a professor at the University of Minnesota. All right, so without further delay, we'll get to my interviews with Jamie and Jim.
Jamie Vaudrey (04:30):
I'm Jamie Vaudrey, and I work at the Connecticut National Estuarine Research Reserve and the University of Connecticut and the Department of Marine Sciences.
Jeff Berckes (04:38):
Well, Jamie, thank you so much for joining me on the Clean Water Pod.
Jamie Vaudrey (04:42):
Yeah, thank you for having me. All right.
Jeff Berckes (04:44):
So before we get into nitrogen and nitrates, let's hear a little bit about you. Where did you grow up? Where did you go to school? And why did you get into water quality?
Jamie Vaudrey (04:54):
Well, I grew up in Vermont right on the Canadian border. In fact, we could see the border I'm from our backyard, so nowhere near the ocean. But I grew up loving the ocean visiting my family at the ocean wishing I lived there. I always knew from a young age that I wanted to go into marine science. What I didn't know is I wanted to go into water quality, which is where I ended up. After after growing up in Vermont, I went to college, Wellesley College in Boston, and then I headed down to the Florida Keys, where I worked at the Newfound harbor Marine Institute for a couple years doing environmental education down on Florida's coral reefs and sponge flats. Then I headed out to Oregon, where I did some more environmental education, and finally decided it was time to go back to, back to school, and came back to graduate school at the University of Connecticut and never left. I stayed there and got my graduate degree, my PhD and carried on as a postdoc, which is what we do after we get a graduate degree, and then became research faculty. And then, actually, a year ago, the Connecticut National Estuarine Research Reserve opened, we're the 30th Research Reserve in the nation. This is a NOAA funded project, it really ties in with that water quality piece, because one of our main goals is to look at human land use and how that impacts our coastal water quality, both from the research standpoint, but also through stewardship, education and training, we're getting that information about water quality, the issues around water quality, and what we can do to improve our environment through the programs of the reserve.
Jeff Berckes (06:46):
Great. So let's talk about nutrients. So let's just start there with the word nutrients. I think it's kind of an interesting word in this context, because when we hear the word nutrients, we think good things, right, like, nutrients are good, they're nutritious, those are good things. But when we get into water quality, some nutrients are good, but we quickly get too much nutrients. And then that's all of a sudden, a really bad thing. So let's just start there with nutrients, what they are and what they do in the water.
Jamie Vaudrey (07:13):
Yeah, so nutrients are definitely a good thing. But just like, you know, pizza, pizza is great in moderation, you have it every once in a while you eat a few slices, but you don't want to eat a pizza every day. So the same applies to nutrients where, you know, we need these nutrients in our coastal oceans. That's that the nutrients coming off the land into the coastal waters, is what lets us have productive shellfish. It gives us our oysters and clams and our lobster, it, it feeds the fish that grow up so you can go fishing and enjoy that coastal water. The problem comes when there are too many nutrients and then you start to over fertilize our coastal oceans. And that's when you start to get into the water quality problems.
Jeff Berckes (08:01):
So when we're talking about nutrients, what are we talking about specifically?
Jamie Vaudrey (08:04):
Well, when we're talking about nutrients in the coastal ocean, we often really mean nitrogen, but it's a whole suite of nutrients. So in, in, we have nitrogen and phosphorus and then a lot of smaller, less well known nutrients like silica, or even iron. And all of those are important for the primary producers that live in our coastal waters. So on land, our primary producers are plants, in the ocean, we have a few plants literally we have about 50 different species of plants, but mostly it seaweed and microscopic plant like organisms called phytoplankton. So in the coastal ocean, we worry about nitrogen because nitrogen is our limiting nutrient, meaning that there's not much nitrogen around in the normal ocean system in our saltwater systems. Whereas when we're talking about freshwater systems, phosphorus is the issue because phosphorus is what's missing in those freshwater environments. So it does change you know, we care about phosphorus in the coastal ocean, but nitrogen is our big problem. Both because the coastal plants and animals they are, they are designed to suck up nitrogen as soon as it's available to them. So if we give them a little extra nitrogen, it can really rev up their production. And we can forget problems like seaweed blooms, or red tides or these green tides, the algae that's washing up along the the beaches of Florida. So again, little bit of nutrient great, but a lot is problematic.
Jeff Berckes (09:50):
It almost seems like a buffet first like for these plants, right? So they just have a lot and it seems really great and then it just gets out of control really quick. So, when you talk about green tides and red tides and all these different colors of tides, what does that mean? And what are the dangers that come with that?
Jamie Vaudrey (10:08):
Sure. So it is very, the impact that nutrients have on our environment are very dependent on the system in, where I'm from in Long Island Sound, we have a very urbanized estuary. So we have lots of people living along the coast, we're on that corridor between Boston and New York City. So there are a lot of people along the coast. That, that leads to a lot of nutrient output. So nutrients, the, the nitrogen comes from our fertilizer, from our sewer treatment plants, and our septic systems. So that's how we deal with human waste. Even a well functioning septic system, it was never designed to remove nitrogen. It's, it's designed to take down the bacteria loads and make that septic water safe, but not remove the nutrients. So we're fertilizing those coastal oceans. So the nutrients stimulate productivity in the environment. And it looks very different depending on where you are. There are places that get seaweed blooms, so you'll get literally three feet of seaweed piling up on the beach. That causes problems, because you know, we don't want to go to the beach and swimmin in three feet of green seaweed, but it also causes problems in the environment, because that's, that's living matter. It creates a compost pile on the beach. And that compost pile on the beach, or under the water can draw down the oxygen in the water. Most people you know, we don't think about oxygen as being a critical resource in the water because as humans, we can't breathe underwater, you know, the oxygen that we need is coming from air. But fish, crabs, clams, all still need oxygen to breathe. They're just designed to pull that oxygen from the water. When you have high productivity, and you have either those phytoplankton, those microscopic plant like organisms in the water that cause things like green tides, and red tides, even beyond the impact that they have on other things in their foodweb, they, they themselves are using up oxygen in the water column. And and that draws down that oxygen. And now you have fish and clams and crabs gasping for breath, basically, you know, they can't get enough oxygen out of that water. So that's one of the big problems that we talk about as an indicator of this nutrient enrichment, or this nutrient pollution. When we see that oxygen dip down to a point where organisms can't survive, or plants and animals are having a hard time surviving, we call that hypoxia. And that's an indication that things are out of balance in the system. The other impact that we get from some of these blooms of green tides, or red tides, or brown tides, Russ tides, they come in all sorts of colors. Those colors reflect who's growing, you know, some of those plant like organisms, those those microscopic plant like organisms, when you get a huge mass of them in the water, the water will literally start to look red, or rust colored, or green or brown. And that's again, an indication of a system that's out of balance.
Jeff Berckes (13:36):
All right, I want to ask about nitrogen specifically. So we talked about nitrogen, I think we talked about nitrate a lot, which is a form of nitrogen. But are there other forms that you're interested in?
Jamie Vaudrey (13:47):
Yeah, there are absolutely other forms. Nitrate is the form that we think of because it's what we apply as fertilizer to to our yard. And it is also the form of nitrogen that we find in groundwater in the freshwater and the groundwater that travels down into the system. But in a system where, and so if you're, if you're in a groundwater dominated system, you have a lot of groundwater coming in a lot of river water, often we're looking at that nitrate. But once you hit the coastal ocean, once that river that's full of nitrate hits the coastal ocean, that nitrate might get converted to something called ammonium. Ammonium is is a reduced form of nitrogen it means the oxygen has been stripped out of it. And we tend to find ammonium in those areas where the oxygen is low in those hypoxic areas. We also find ammonium coming out of our wastewater. So our sewer treatment plants and our septic water tend to have more ammonium in them than nitrate. That's not always true. But in general, that's, that's how it works. The third form of nitrogen that we have is called organic nitrogen, and organic nitrogen is nitrogen that's bound up into stuff, into biological stuff. And that can can literally be something that a biological organism has excreted, has given off, it can be from a decaying plant matter or decaying animal matter. They're locked in these organic compounds. Think of like when we talk about proteins and carbohydrates, they often have nitrogen in them, that as they get broken down, that nitrogen can be released. So similar to, to your garden, if you put a nitrate fertilizer on it, that nitrate is often more readily available to the plants of your garden. If you use an organic fertilizer, like compost, or manure, or you know, the organic fertilizers that you can buy at the hardware store, they say that those take longer because it literally does take longer for the bacteria to break the nitrogen and phosphorus out of that compost and get it to the plants. Same things happening in the coastal ocean. So we have organic nitrogen coming down, which will eventually or could eventually become nitrate, or ammonium, but it does provide nitrogen to the system. And I just want to say, you know, when we're talking about trying to reduce nitrogen that's entering our coastal waters, people will often say, Oh, well, I use I do organic gardening, I apply organic fertilizer to my to my yard. So that's better, right? And there are many reasons why we want to use organic fertilizers, they do break down longer, it's a more natural product, you know, we're recycling manure from our cows or horses and putting it onto the lawn. So that's good. But nitrogen is nitrogen, whether it's organic, or it's nitrate, or ammonium, eventually, it gets broken down and becomes usable by that coastal ocean. So when we're looking at trying to reduce nitrogen to our coastal systems, it's not just switching to organic fertilizer, it's also using less fertilizer, because it's that quantity that matters.
Jeff Berckes (17:18):
So there's another aspect of this as well. Right? So then, so nitrate has a drinking water standard, what can you tell us about that?
Jamie Vaudrey (17:24):
Nitrates getting into our drinking water is one of those water quality issues that we think about on the land. In certain places, the the nitrate levels have been so high that it causes something called Blue Baby Syndrome, where literally, it's impacting young, young infants abilities to take in oxygen, so they look like they're oxygen deprived. I don't know if that's still, still happening right now. Because now with our freshwater processing, you know, we're in places where that is likely to happen. People are more aware of it with well water testing, and are using alternate sources of water. But that's just one example of the impact that nitrogen in our freshwater can have on us on its own nitrogen is generally not harmful to us as human beings like we can drink nitrogen with rich water for the most part, and be fine. What happens though, is that as that nitrogen is in our water, it can start to impact things like allowing bacteria to grow more robustly, we get we get more bacterial growth in a system. It also has an impact on freshwater lakes. You know, in the freshwater lakes, we are often talking about phosphorus is that limiting nutrient. But if you add a little nitrogen with that phosphorus, it can make that lake system much more productive. Similar to on the coastal ocean. Yes, we care about nitrogen. But if you have nitrogen and some phosphorus, it grows, those plants will grow even more robustly, they'll grow more aggressively than if you have just nitrogen alone. So looking at that balance is also important.
Jeff Berckes (19:10):
All right. So where does this stuff come from? And what are some of the practices that help try to remove this from the environment?
Jamie Vaudrey (19:18):
Yeah, so that's a great question. Nitrogen comes from three main sources. We have the nitrogen that comes from our waste. We are We are humans, we live on the land, we eat, and we excrete, and we are nitrogen recyclers, we are nutrient recyclers. So we're taking in nutrients, living and putting nutrients out. Since the 1970s. We have recognized that that nutrients are an issue. And over time, our ability to handle our wastewater has improved. You know, first, we started by just removing the things that were going to cause bacterial problems. Nowadays we're into nitrogen-removing sewer systems and nitrogen-removing septic systems. And what that is doing is it stripping the nitrogen out of our waste products, and putting it into other forms often into turning it into a gas, which goes into the air and is the inert, meaning that it's not, it's not accessible to plants once it's nitrogen gas, or locking it into solid form. So the nitrogen-removing septic systems do that in a couple of different ways. But one of the ways that we can remove nitrogen is by literally putting a type of wood chip in the ground. And so as the freshwater flows through this bed of woodchips, the bacteria that are living in those woodchips are taking up that nitrogen and locking it into biomass that's under that's underground. So being supportive of these initiatives to upgrade wastewater treatment plants to remove nitrogen is really critical. We've seen a big improvement in Long Island Sound from from this nitrogen reduction strategy to improve our sewer systems, to remove that nitrogen. We kind of reached a plateau in our ability to remove nitrogen from our sewer systems. And we've done all that we can do right now, that's not quite true, we haven't done all that we can do. But we've done a lot of what we can do. And so the attention is really focused to what we call nonpoint sources. So if you think of a point source, that's our sewer treatment plant, you can literally point to a pipe and say that's where the nitrogen is coming from the nonpoint sources are much harder to go after. Because they're things like your individual septic system that's at your house treating your wastewater, or it's the fertilizer that you're applying to your lawn, or that the farmer is applying to their field. The third source of nitrogen that we get, the third source of nitrogen is from atmospheric deposition. And that's basically the rain and the dust that settle onto the land. And that includes nitrogen in it. So when you're when you catch a handful of rainfall, it's fairly well loaded with nitrogen. Again, it's gotten better over time, with the advent of the Clean Air Act, we are seeing reductions in the pollutants that are in our rain. But, but we do still get that fertilizing impact of rain, snow and dust from atmospheric deposition. So you asked how do we how do we treat it? How do we fix it? You know, first of all, you have to identify the sources. So those are our three sources, the fertilizer, the human waste, and the atmospheric deposition. There are natural sources of nitrogen. But the issue is not those natural sources. It's it's what we as humans are doing that's having an impact on that coastal water quality. So we want to go after those humans sourced those human sources. on kind of a society level, those big infrastructure improvements to our sewer systems are important. But on a personal level, we can reduce our nitrogen in many different ways, including reducing the amount of fertilizer that we're using. We often when we're trying to get communities to reduce their fertilizer, we have a few basic guidelines, you know, you want to fertilize your lawn when your lawn is growing. And so that means that it when when your lawn goes dormant in the middle of summer, which happens here in Connecticut, don't fertilize your lawn. When it's the middle of winter. don't fertilize your lawn, the grass is not growing, it cannot take up that nitrogen. So fertilize when you're when your lawn is growing. And that's usually around Memorial Day or Labor Day. A big one though, is if you like the way your lawn looks, don't do anything. If you like the way your lawn looks, it means it has enough nitrogen, it has the right, the right conditions, it's happy. You don't need to continually add nitrogen to it. An established lawn needs relatively little nitrogen, so stop the nitrogen use on your lawns. But I tell people you know, yes, we are water quality may be relatively poor here because we've got nitrogen coming into the system, but often it's swimmable, often it's fishable. So it's a, it's a, the environment needs a much higher level of purity or quality than we do as humans. And that's that's part of the problem. You know, if it were physically harming us to have this poor water quality, I think that there would be a lot more action taken a lot more immediacy, a lot more urgency. People would care more if going in the water was harmful to us. But it's not harmful to us. It's just harmful to the blue fish and the crabs
Jeff Berckes (24:58):
which of course can be harmful to us. In the long run, because that costs us more to harvest and eat those good things that we like to eat. But, Jamie, I really want to thank you so much for your time. And thank you for joining us and sharing your expertise on the clean water pot.
Jamie Vaudrey (25:11):
Well, thank you for your interest.
Jeff Berckes (25:20):
Okay, that was my interview with Jamie Vaudrey, from Connecticut. We're going to shift over now to talk to James Cotner, from the University of Minnesota about phosphorus.
And I'm pleased to welcome Jim Cotner to the Clean Water pod. Jim, welcome.
Jim Cotner (25:40):
Thank you. It's great to be here.
Jeff Berckes (25:42):
All right, well, really excited to dive into this topic of nutrients. But before we get going, I want to know, where are you from? Where did you go to school? And why the heck did you choose water quality is what you did with your life?
Jim Cotner (25:55):
Great question. So I grew up in the Midwest, but not in Minnesota. I grew up in Ohio. I, I basically imprinted on water. As a kid, I came from a family of swimmers, but I also imprinted early on in the Great Lakes. I basically went fishing with my grandfather, and that, that meant a lot to me. And I think that's one of the reasons I just love being around the water.
Jeff Berckes (26:27):
So let's talk about phosphorus. And I want to talk about this concept of, it's a nutrient. So let's start there. Because I think a lot of people hear nutrients and they think that's good. We need nutrients to live nutrients are a good thing. But when we talk about water quality, we so very quickly get into nutrients being a bad thing. So why don't we just kind of establish what the nutrients are, and why they're present and how they're good for water quality, but then in excess can be bad. So let's let's just start with the the concept of nutrients. Yeah, so
Jim Cotner (27:01):
there are lots of different nutrients that we need in order to make cells or biomass. And we talk about in water quality, we talk about macronutrients and micronutrients. So macronutrients are things like carbon, nitrogen, and phosphorus, oxygen, hydrogen. So these are the things that we need the most in our cells. And micronutrients are things like molybdenum, or iron, or cobalt, things that we need in order to make cells, but we need a lot less of them. And so nitrogen and phosphorus are macronutrients. But they're also nutrients that are very commonly limiting in freshwater and marine ecosystems.
Jeff Berckes (28:04):
Alright, what do you mean by limiting? What does that mean specifically?
Jim Cotner (28:09):
Great question. So limiting means that, you know, if you're going to put a cell together, you need all those things carbon, nitrogen, phosphorus, oxygen, hydrogen, sulfur, you need them in a certain ratio, okay? You don't need as much phosphorus as you need carbon. And you don't need as much nitrogen as you need carbon. But you need all of those things in order to make proteins and cells. And if one of those is missing, or available at lower concentrations than what you need it as, then it will be limiting. And the way I explain this in my classes is, it's, it's sort of like an assembly line, you know, you're putting together a vehicle and you need a certain number of wheels, you need a certain number of axles, you need a certain number of transmissions, and so on and so forth. That number is different depending on what part you're looking at, right? But if, if one of those parts isn't being produced at you know, the factory that supplies the assembly line, at a high enough rate, it becomes limiting. So let's say axles are produced at a different factory. And that factory goes on strike well axles become a limiting process in terms of how many cars you can make, and it's the same idea with cells. So if, if you need phosphorus at a certain level, and it's low relative to everything else, it becomes limiting to the production of cells.
Jeff Berckes (30:13):
Okay, so when we talk about water quality, let's talk about the good aspect of what presence of phosphorus can bring. Right? So there because there is a positive here, again, it's a nutrient. So what does it provide in the positive aspects?
Jim Cotner (30:29):
Well, essentially, many of our freshwaters, because they are phosphorus limited when you have phosphorus available for the cells. For, you know, for algae and bacteria, and the plants that are growing in that system. When there's plenty of phosphorus, they can grow, essentially, to a very significant extent, I'm not going to say, to an unlimited extent, because other things become limiting. If you add more phosphorus, for instance, if you're an Alga that's growing in the water column of a lake, and you add phosphorus, and that system is phosphorus limited, you're gonna get more and more algae and, but eventually, the algae attenuates the light that's in the lake. So it blocks out the light. So that light becomes limiting. And similarly, if light doesn't become limiting, perhaps something like nitrogen or carbon becomes limiting. So eventually, all those things have to balance in order for you to get unlimited growth, basically. What we want in a balanced, what we want is a balanced system, essentially. So if you have nitrogen and phosphorus and carbon, at a steady state, where they don't accumulate to any significant extent, that's when everybody the whole ecosystem is happiest, right? But when they get out of balance is when you get excessive growth. And excessive growth is problematic, because when all those algae decompose, they lead to low oxygen, or even no oxygen conditions in the bottom of the lake, or a river or a pond. And those low, or no oxygen conditions are not good for everybody, essentially, that's living in that ecosystem, except for bacteria. And we can't eat bacteria. We want to eat fish. And so essentially, what we want is a balanced ecosystem, where nitrogen phosphorus are not in excess, relative to the needs of the algae, and the organisms that eat the algae.
Jeff Berckes (33:14):
This might be a silly question, Jim. But fish breathe underwater, right? Like that's, I think that's something that we maybe just kind of need to establish that the you know, the the fish that are in the, in the water in the lakes that we're trying to grab with our fishing poles, they need something called dissolved oxygen to survive. And the amount of algae, like you're saying, can really complicate things if there's too much as it dies back. So can you maybe talk a little bit about that?
Jim Cotner (33:44):
Sure. So yeah, as you mentioned, Jeff, there's a certain amount of oxygen that's dissolved in the water, and that's a function of two things. The first thing is it's in equilibrium with the atmosphere. So there's, about 20% of our atmosphere is oxygen. And so it's sort of, you know, like a can of soda. So if you put a bunch of co2 in a can of soda, it's gonna dissolve into the Can of soda and that's what carbonates are Can of soda. So there's oxygen in the atmosphere that is oxygenating the water, okay. And lots of organisms depend on that oxygen in order to metabolize. So fish are just like us. So they, they consume oxygen and produce co2 through their metabolism. And the way they get oxygen is from that dissolved oxygen in the water, it absorbs they absorb the oxygen across the gills, basically, and it goes into their bloodstream that way. But another way ironically, that oxygen gets into the water is through photosynthesis from plants. So remember, we were talking about algal blooms. So an algal bloom. When those algae are photosynthesizing, they produce oxygen as a waste of photosynthesis. And that helps increase the amount of oxygen in the water. But when those algae decompose, that's when that oxygen gets consumed. And one of the things that happens, particularly in lakes and ponds, is that the algae are photosynthesizing and producing excess oxygen at the surface. And then they fall to the bottom of the lake or the bottom of the pond, where the oxygen is consumed through decomposition, mostly bacteria that are consuming them. And when that happens, the oxygen disappears. And, you know, if you're a fish, and you don't live at the surface, where the oxygen concentrations are going to be higher, that can be problematic, of course.
Jeff Berckes (36:09):
So one of the things that an algo Blum can do to a fishery is lead to something called a fish kill, which is something that we see in our impaired waters list, one of the episodes that we had last year where we focused on impaired waters lists, one of the things that you might see on an impaired waters list in the state you live, is something called a fish kill. So do you know much about that concept? And what leads to that? And sort of what? Basically what happened there, right, is that an algae bloom leading to a fish kill, and the overall health of the fishery?
Jim Cotner (36:46):
Yeah, so fish kills are becoming more common actually, across the US and actually globally. And there's a number of factors there, one of the biggest ones, obviously, are algal blooms. And so as I mentioned, those algal blooms lead to the accumulation of organic matter or algal biomass. And when that falls to the bottom, it can consume all of the oxygen and make it such that the fish can't survive. So, you know, there are certain fish that live in deeper water. In Minnesota, you know, some of those fish are ones that we like to catch like walleye, or lake trout. And those fish are particularly susceptible to this phenomenon. So when the algae falls to the bottom, they're going to decompose consume the oxygen and potentially kill those fish off, because they can't go to the surface because the water is too hot for them there.
Jeff Berckes (37:51):
Basically if you get these conditions where you have too much phosphorus, and you get too much algae, you get algae blooms, or just get too much algae, it can lead to, you know, an ungainly appearance, right? There's some it's not a lake that you're going to want to be around may have a smell to it, right? It's not going to look very pretty, it's certainly not something that you're going to want to wade into if there's a beach, on that lake or anything like that, right. So there's, there's some human components there that you may not be interested in from an aesthetic standpoint. But from the fisheries standpoint, that really ties into a lot of tourism, or even just that enjoyment for that local community around that lake that likes to use that as a fishing resource. And if you don't have the right water quality, if if the water quality is suffering, because of those inputs, you're not going to be able to grow those sport fish that you want to catch the fisheries really going to change, right, you're just going to have, you know, rough fish or things that maybe aren't as fun to catch.
Jim Cotner (38:56):
Exactly. So a lot of the rough fish are better able to deal with low oxygen conditions. Basically, there are some of those rough fish, they have hemoglobin that's different. So it can hold on to oxygen more effectively. And some of them actually are able to gulp air from the atmosphere. But those fish are usually not the ones we want to catch. The ones we want to catch are more susceptible, and climate change is in addition to increased nutrients coming from the landscape, climate change is feeding into this problem as well. And the way climate change matters is that when if you swim in a lake in the summertime, you can tell that there's a temperature difference from the surface to the bottom so you dive down and you can tell it's colder at the bottom. That cold water at the bottom is where cold water fish like walleye and lake trout reside, the cold water actually holds more oxygen. But the problem is that climate change is making it so that you have those stratified conditions where the surface water sits on top of the bottom water for a longer period of time. So it's sort of like the fish are in this enclosed mass of water with no exchange with the atmosphere. So there's no new oxygen coming into that system. And with climate change, lakes are staying in that summer stratified state for longer periods of time. And what that means is the oxygen that's in the bottom of the lake is being depleted for longer periods of time and making the habitat for the fish that live down there more vulnerable.
Jeff Berckes (41:04):
When we talk about phosphorus. And we mentioned a little bit particularly in the Midwest, we talked about fertilizers. What are the sources of phosphorus, do you have like a somewhat comprehensive list of where this is coming from, and how this is entering our waters?
Jim Cotner (41:20):
Well, Phosphorus is in all living organisms, okay. So it makes up about anywhere from one to 3% of all of us, you know, from microbes to elephants, basically, that's where a lot of it comes from. And so, in aquatic systems, as we talked about, a lot of the nitrogen and phosphorus is just coming from organisms that are already in the lake that are decomposing. Okay. So that's a major source. But when we tend to get excessive algal blooms, we also have phosphorus coming in from the surrounding landscape at relatively high rates. And that can be from decomposition of organisms in the upstream region. But increasingly, it's probably problematic in that it's coming from fertilizer use. And we do a great job of growing things. In the Upper Midwest, we have great soils, we have flat landscape, which makes for excellent conditions for farming. But in order to maintain the ideal conditions for farming in the Upper Midwest, we add phosphorus to the landscape in the form of fertilizer. But as we mentioned, that fertilizer doesn't all end up in the crops that we harvest. And that's where the problem comes from. So if it stayed, if it all went into the crops, we wouldn't have a problem. A bunch of it runs off into the surrounding aquatic systems. One of the things we haven't talked about that I should make everybody aware of is the fact that this whole phenomenon can lead to positive feedbacks. So and what I mean by a positive feedback is that if you add more phosphorus, it tends to accelerate the eutrophication process. So think of it this way. So we add phosphorus on the landscape that runs off into a lake. It leads to an algal bloom that occurs in the lake, the algae grow, they die, they fall to the bottom, and they decompose. Those low oxygen conditions are a result of decomposition also make it so more phosphorus comes out of the sediments and back into the water column. That's called internal phosphorus loading. So you think of all the organisms that have lived in that lake, over decades to millennia, they fall to the bottom, most of them decompose and release nutrients back into the water, but a lot of them just don't completely decompose. So a lot of the phosphorus stays in the sediments. Those low oxygen conditions actually make it easier for the phosphorus to migrate out of the sediments and into the water column.
Jeff Berckes (44:46):
So basically, what you're saying is that you have a faucet that's on that has that's bringing in a certain amount of phosphorus every year because of excess fertilizer or maybe a failing septic systems up in the watershed. How ever its getting into the into the water, there's a faucet coming in. And every year, whatever is coming in certain amount of that is going to just settle at the bottom of the lake and not leave the lake. And then every year, you get a little bit more kind of a bio accumulation of some kind in that lake. So as we move forward, it's more likely that we're going to get future algal blooms because of that influence of the faucet on.
Jim Cotner (45:29):
Yes, that's exactly right. And a critical turning point is when the sediments become anaerobic. So there's, there's no oxygen left. And so most lakes go through a cycle, you know, over their lifespan, where initially they're deep, and oxygen concentrations are high throughout the lake. But as lakes get more productive, you know, if there's more algal blooms, basically, there's more algae that fall to the bottom, consume the oxygen and lead to this acceleration process. The other thing that's important about that is that as that material falls to the bottom of the lake, it continues to get shallower and shallower over its lifespan. And what that means is more of those nutrients are closer to the surface of the lake where the algae are able to grow. So it's like you're you're bringing the nutrients closer to where they're, they're being used by the algae, and it's all just accelerating.
Jeff Berckes (46:47):
Okay, so now let's talk about how we fix this. Right. So two questions, one, how do we turn off that faucet, which the input that is coming in from the rest of the watershed? And then the second part of that is, once you maybe get that faucet turned down, or, or turned off to a reasonable extent, how do you clean up the lake itself?
Jim Cotner (47:09):
Great questions. There, those are difficult questions. If they were easy questions, we would have fixed them by now, but they're not. And so the main, the main way to start to fix the process is to eliminate or at least attenuate the sources of those nutrients. And we've done a lot of great things along those lines in the US. Okay. So one of the things we realized back in the 50s and 60s is that phosphorus was a problem. And we first started to notice this in a few fairly large Lakes, Lake Erie is sort of the poster child for this. So back in the 50s, and 60s, they noticed that these low oxygen conditions were leading to a die off of insects, which were important feed for a lot of the fish in Lake Erie, okay. And so, and they, when they realized that phosphorus was a big problem, one of the first things they did was they did a much better job of removing phosphorus in sewage. So, as we've have talked about phosphorus is in all organisms, including us. And so our waste is full of phosphorus. And so when we flush the toilet, we're sending a lot of phosphorus to the sewage treatment plant. And so sewage treatment plants in the 70s 80s and 90s got really good at removing phosphorus. And they do that a number of different ways. One of the big ways is just to pull as many particles out of the water as possible, because phosphorus is not very soluble. And so if you can get rid of the particles in the water, you can get rid of a lot of phosphorus. But another thing that they do at sewage treatment plants is a lot of sewage treatment plants will treat the water with alum or ferric iron. And those chemicals react with phosphorus and remove it from the water and put it into a particulate form which you can filter. Okay. And so if you do that you can remove upwards of 90% of the phosphorus that's coming into a sewage treatment plant. It's a little bit more problematic on landscapes, but the principles are the same. So And as we mentioned, a lot of the phosphorus, on landscapes in agricultural settings in particular is in particulate form. One of the ways we try to keep phosphorus out of aquatic systems is by putting buffer strips around aquatic systems or around farmed systems, until a buffer strip is just a strip of land, where you have plants that grow and thrive, when you present them with lots of nutrients. So, you know, it can be wetlands, it can be forested systems, basically systems that are able to thrive on the nutrients, and remove them, and put them into their own biomass before it gets into the aquatic system, where it can do a lot of harm. So there are a lot of best management practices that are essentially focused on exactly that. Okay. Finally, the last thing that you can do is remove the nutrients once they're in the lake, or in the river, or in the pond. And, again, essentially what that comes down to, there's different ways of doing that. But one of them is just similar to what you do in a sewage treatment plant, you just add iron, or aluminum as hydro- in the hydroxide form. And that will bind the phosphorus and pull it down into the sediments. And it's bound in such a way that it won't be released, if the water column becomes anoxic or no oxygen left in it. In many lakes in the Upper Midwest, one of the practices that is commonly used is a harvester. And so a harvester is just a large contraption to cut the plants that are growing from the sediments. So, you know, milfoil is, is one of those coontail is another one that's commonly harvested. And so basically, it's they cut the plants, they have a little conveyor belt that pulls the plants up from the bottom of the lake and just puts it into a big bin. And then that bin is removed from the lake. And so as we said, there's lots of nitrogen and phosphorus in those plants. So when you remove the plants, you're removing those nutrients. The last thing that is commonly used in a lot of lakes is is just to artificially add oxygen into the lake. And so many of us are familiar with lakes, you'll that you'll see bubbling, especially in the wintertime in the Upper Midwest, so they're just adding oxygen to the lake. And that does two things. It provides habitat for the fish that require the oxygen. But it also makes it so that the phosphorus that's in those sediments of those lakes, is more likely to stay in the sediments rather than come to the surface where the algae can use it.
Jeff Berckes (53:29):
Well, it seems to me like you talked about putting oxygenation, contraptions inside of lakes, that seems like a bit of a treatment type, they may not even treatments the right thing, but just kind of like life support. So you know, to cover yourself over the winter months, you know, you talked a little bit about treating with with with an alum with, you know, with an aluminum or an iron to try to capture that at the bottom, you know, that seems like treatment of the symptom a little bit. Whereas the harvesting of the plant matter, then you're over time you're removing that phosphorus from the system. So I would think that that would be more of a long term fight that would eventually get you better results. How long do you typically see that kind of approach take until you really start to see some significant differences?
Jim Cotner (54:28):
Well, that's a great question, but a lot of it depends on the lake that you're working in. And how bad it is. You know, I will say that the most appropriate strategy is to start in the watershed. So those best management practices or you know, like removing nutrients via sewage treatment, or best management practice says before it gets into the lake, that's the best way. Okay, in an ideal strategy, what you what you would do is start there. And then potentially, you know, something like harvesting would be another strategy for removing nutrients once they're in the lake. And that one is fairly straightforward. But it's also not cheap. And then alum is a is a treatment as more and more commonly being used in lakes as well. So you have basically those, those three major levels, but you have to start in the watershed. And if you do that in, in combination with something like harvesting, you know, in a smaller lake, you're gonna see effects on relatively short term. I mean, the harvesting, you see the effects, you know, very quickly. But it might take on the order of years to decades before, the combination of those two processes leads to significant results in the behavior of that system. But a lot of it depends on how big the system is, you know, the bigger the lake and the further along you are in the eutrophication process, the longer it's going to take. It's sort of like inertia, and you have to overcome that inertia in orders sort of set the clock backwards in terms of nutrient management.
Jeff Berckes (56:41):
Well, Jim, I really appreciate your time and your expertise and for coming on to the Clean Water pod to share that with us.
Jim Cotner (56:48):
Well, it's been an excellent experience for me, and I love talking about phosphorus. So happy to do it.
Jeff Berckes (56:58):
All right, that is our first episode of season two. I hope you all enjoyed this kickoff episode. Please join us next month for Episode Two as we dive into success stories associated with nutrients in our nation's waters. If you have any questions about this or future episodes, please get in touch. You can find us on Twitter at cleanwaterpod or send me an email at cleanwaterpod@gmail.com. We'd love to hear from you, what questions you have, and what you'd like to hear on the pod. Until next time. Thanks for listening
Welcome to Season Two of the clean water pod, the show about the challenges and successes in restoring and protecting water quality. My name is Jeff Berckes, and I'm talking to dedicated professionals across the country to build an understanding of how policy and science work together to meet the goals of the Clean Water Act for fishable, swimmable and drinkable water quality in our nation's waters. We've got to change this year's show is Sarah Schwartz is on assignment. And we'll be joined by another EPA friend, Teagan Rostock. Teagan, welcome to the Clean Water Pod.
Teagan R, EPA (00:54):
Thank you, Jeff, for having me.
Jeff Berckes (00:56):
Well, we're really excited. And like we ask all of our guests, we want to know a little bit about you. So where did you grow up? Where do you go to school? And how did you get into water quality.
Teagan R, EPA (01:07):
I grew up in South Florida. And I was lucky enough to live right next to the Loxahatchee River, which is a really beautiful river surrounded by mangroves. It's filled with manatees and alligators, and all kinds of beautiful birds and other wildlife. And because of that, I really became passionate about water quality. And I went to school at University of Florida, and got my degree in natural resource management. And then I went on to Duke and got a degree in environmental management. So I have my master's degree.
Jeff Berckes (01:44):
So you right away thought, this is for me water quality. So from a young age, this is what you wanted to do. You you had the direct course through college, and then you found yourself with the Environmental Protection Agency.
Teagan R, EPA (01:57):
Yep, never changed my mind, I always wanted to do this.
Jeff Berckes (02:02):
So you are the rarity, because I gotta tell you, although in water quality, we find this a lot. There's a lot of passion early on that drives people to this career. So not unique in that. But overall, that's not necessarily the most common path for people to know exactly what they want to do. So there is something bonding about that water quality element. So this year, we're going to be focusing on nutrients and water quality, we're gonna be focusing all around the country on different success stories, people that are working on different nutrients and showing some successes and cleaning up some of our nation's waters. And we've got some great guests to kick that off. But I want to ask you, the EPA expert here to define the term eutrophic for us.
Teagan R, EPA (02:47):
Yeah. So eutrophication describes the buildup of excess nutrients such as nitrogen and phosphorus and a body of water. And in this podcast, you will hear a lot about nitrogen and phosphorus.
Jeff Berckes (03:00):
Yeah, absolutely. Right. So you know what, what I find interesting about eutrophication and this idea of eutrophic conditions and waters is that it comes down to these things called nutrients, which, you know, we want they're, they're desirable, nutrients are good, but if you have too many nutrients and water, you can start to get some issues. And so, to be able to help us understand that a little better, I interviewed two professors. And I want to know before we get into the interviews, did you have a favorite professor at the University of Florida?
Teagan R, EPA (03:32):
I had a few favorites. I don't think I could choose one.
Jeff Berckes (03:36):
Oh, that's good.
Teagan R, EPA (03:37):
Really great professors. Yeah,
Jeff Berckes (03:39):
well, I don't know that I have a favorite professor. But I remember I had a professor that went by Ace. His last name was Ventulo. So very close to Ace Ventura, Ace Ventulo. And he wore a lot of Hawaiian shirts, a very common ecologist kind of thing to do. Again, not sure if I remember him as my favorite, but certainly an interesting character. These two people that I interviewed for this podcast, I think, are probably a lot of people's favorite professors. The first professor that you're going to hear from is Jamie Vaudrey. She is an expert on nitrogen, and a professor at the University of Connecticut. And then about halfway through the episode, we'll switch over to my interview with Jim Cotner is an expert on phosphorus and a professor at the University of Minnesota. All right, so without further delay, we'll get to my interviews with Jamie and Jim.
Jamie Vaudrey (04:30):
I'm Jamie Vaudrey, and I work at the Connecticut National Estuarine Research Reserve and the University of Connecticut and the Department of Marine Sciences.
Jeff Berckes (04:38):
Well, Jamie, thank you so much for joining me on the Clean Water Pod.
Jamie Vaudrey (04:42):
Yeah, thank you for having me. All right.
Jeff Berckes (04:44):
So before we get into nitrogen and nitrates, let's hear a little bit about you. Where did you grow up? Where did you go to school? And why did you get into water quality?
Jamie Vaudrey (04:54):
Well, I grew up in Vermont right on the Canadian border. In fact, we could see the border I'm from our backyard, so nowhere near the ocean. But I grew up loving the ocean visiting my family at the ocean wishing I lived there. I always knew from a young age that I wanted to go into marine science. What I didn't know is I wanted to go into water quality, which is where I ended up. After after growing up in Vermont, I went to college, Wellesley College in Boston, and then I headed down to the Florida Keys, where I worked at the Newfound harbor Marine Institute for a couple years doing environmental education down on Florida's coral reefs and sponge flats. Then I headed out to Oregon, where I did some more environmental education, and finally decided it was time to go back to, back to school, and came back to graduate school at the University of Connecticut and never left. I stayed there and got my graduate degree, my PhD and carried on as a postdoc, which is what we do after we get a graduate degree, and then became research faculty. And then, actually, a year ago, the Connecticut National Estuarine Research Reserve opened, we're the 30th Research Reserve in the nation. This is a NOAA funded project, it really ties in with that water quality piece, because one of our main goals is to look at human land use and how that impacts our coastal water quality, both from the research standpoint, but also through stewardship, education and training, we're getting that information about water quality, the issues around water quality, and what we can do to improve our environment through the programs of the reserve.
Jeff Berckes (06:46):
Great. So let's talk about nutrients. So let's just start there with the word nutrients. I think it's kind of an interesting word in this context, because when we hear the word nutrients, we think good things, right, like, nutrients are good, they're nutritious, those are good things. But when we get into water quality, some nutrients are good, but we quickly get too much nutrients. And then that's all of a sudden, a really bad thing. So let's just start there with nutrients, what they are and what they do in the water.
Jamie Vaudrey (07:13):
Yeah, so nutrients are definitely a good thing. But just like, you know, pizza, pizza is great in moderation, you have it every once in a while you eat a few slices, but you don't want to eat a pizza every day. So the same applies to nutrients where, you know, we need these nutrients in our coastal oceans. That's that the nutrients coming off the land into the coastal waters, is what lets us have productive shellfish. It gives us our oysters and clams and our lobster, it, it feeds the fish that grow up so you can go fishing and enjoy that coastal water. The problem comes when there are too many nutrients and then you start to over fertilize our coastal oceans. And that's when you start to get into the water quality problems.
Jeff Berckes (08:01):
So when we're talking about nutrients, what are we talking about specifically?
Jamie Vaudrey (08:04):
Well, when we're talking about nutrients in the coastal ocean, we often really mean nitrogen, but it's a whole suite of nutrients. So in, in, we have nitrogen and phosphorus and then a lot of smaller, less well known nutrients like silica, or even iron. And all of those are important for the primary producers that live in our coastal waters. So on land, our primary producers are plants, in the ocean, we have a few plants literally we have about 50 different species of plants, but mostly it seaweed and microscopic plant like organisms called phytoplankton. So in the coastal ocean, we worry about nitrogen because nitrogen is our limiting nutrient, meaning that there's not much nitrogen around in the normal ocean system in our saltwater systems. Whereas when we're talking about freshwater systems, phosphorus is the issue because phosphorus is what's missing in those freshwater environments. So it does change you know, we care about phosphorus in the coastal ocean, but nitrogen is our big problem. Both because the coastal plants and animals they are, they are designed to suck up nitrogen as soon as it's available to them. So if we give them a little extra nitrogen, it can really rev up their production. And we can forget problems like seaweed blooms, or red tides or these green tides, the algae that's washing up along the the beaches of Florida. So again, little bit of nutrient great, but a lot is problematic.
Jeff Berckes (09:50):
It almost seems like a buffet first like for these plants, right? So they just have a lot and it seems really great and then it just gets out of control really quick. So, when you talk about green tides and red tides and all these different colors of tides, what does that mean? And what are the dangers that come with that?
Jamie Vaudrey (10:08):
Sure. So it is very, the impact that nutrients have on our environment are very dependent on the system in, where I'm from in Long Island Sound, we have a very urbanized estuary. So we have lots of people living along the coast, we're on that corridor between Boston and New York City. So there are a lot of people along the coast. That, that leads to a lot of nutrient output. So nutrients, the, the nitrogen comes from our fertilizer, from our sewer treatment plants, and our septic systems. So that's how we deal with human waste. Even a well functioning septic system, it was never designed to remove nitrogen. It's, it's designed to take down the bacteria loads and make that septic water safe, but not remove the nutrients. So we're fertilizing those coastal oceans. So the nutrients stimulate productivity in the environment. And it looks very different depending on where you are. There are places that get seaweed blooms, so you'll get literally three feet of seaweed piling up on the beach. That causes problems, because you know, we don't want to go to the beach and swimmin in three feet of green seaweed, but it also causes problems in the environment, because that's, that's living matter. It creates a compost pile on the beach. And that compost pile on the beach, or under the water can draw down the oxygen in the water. Most people you know, we don't think about oxygen as being a critical resource in the water because as humans, we can't breathe underwater, you know, the oxygen that we need is coming from air. But fish, crabs, clams, all still need oxygen to breathe. They're just designed to pull that oxygen from the water. When you have high productivity, and you have either those phytoplankton, those microscopic plant like organisms in the water that cause things like green tides, and red tides, even beyond the impact that they have on other things in their foodweb, they, they themselves are using up oxygen in the water column. And and that draws down that oxygen. And now you have fish and clams and crabs gasping for breath, basically, you know, they can't get enough oxygen out of that water. So that's one of the big problems that we talk about as an indicator of this nutrient enrichment, or this nutrient pollution. When we see that oxygen dip down to a point where organisms can't survive, or plants and animals are having a hard time surviving, we call that hypoxia. And that's an indication that things are out of balance in the system. The other impact that we get from some of these blooms of green tides, or red tides, or brown tides, Russ tides, they come in all sorts of colors. Those colors reflect who's growing, you know, some of those plant like organisms, those those microscopic plant like organisms, when you get a huge mass of them in the water, the water will literally start to look red, or rust colored, or green or brown. And that's again, an indication of a system that's out of balance.
Jeff Berckes (13:36):
All right, I want to ask about nitrogen specifically. So we talked about nitrogen, I think we talked about nitrate a lot, which is a form of nitrogen. But are there other forms that you're interested in?
Jamie Vaudrey (13:47):
Yeah, there are absolutely other forms. Nitrate is the form that we think of because it's what we apply as fertilizer to to our yard. And it is also the form of nitrogen that we find in groundwater in the freshwater and the groundwater that travels down into the system. But in a system where, and so if you're, if you're in a groundwater dominated system, you have a lot of groundwater coming in a lot of river water, often we're looking at that nitrate. But once you hit the coastal ocean, once that river that's full of nitrate hits the coastal ocean, that nitrate might get converted to something called ammonium. Ammonium is is a reduced form of nitrogen it means the oxygen has been stripped out of it. And we tend to find ammonium in those areas where the oxygen is low in those hypoxic areas. We also find ammonium coming out of our wastewater. So our sewer treatment plants and our septic water tend to have more ammonium in them than nitrate. That's not always true. But in general, that's, that's how it works. The third form of nitrogen that we have is called organic nitrogen, and organic nitrogen is nitrogen that's bound up into stuff, into biological stuff. And that can can literally be something that a biological organism has excreted, has given off, it can be from a decaying plant matter or decaying animal matter. They're locked in these organic compounds. Think of like when we talk about proteins and carbohydrates, they often have nitrogen in them, that as they get broken down, that nitrogen can be released. So similar to, to your garden, if you put a nitrate fertilizer on it, that nitrate is often more readily available to the plants of your garden. If you use an organic fertilizer, like compost, or manure, or you know, the organic fertilizers that you can buy at the hardware store, they say that those take longer because it literally does take longer for the bacteria to break the nitrogen and phosphorus out of that compost and get it to the plants. Same things happening in the coastal ocean. So we have organic nitrogen coming down, which will eventually or could eventually become nitrate, or ammonium, but it does provide nitrogen to the system. And I just want to say, you know, when we're talking about trying to reduce nitrogen that's entering our coastal waters, people will often say, Oh, well, I use I do organic gardening, I apply organic fertilizer to my to my yard. So that's better, right? And there are many reasons why we want to use organic fertilizers, they do break down longer, it's a more natural product, you know, we're recycling manure from our cows or horses and putting it onto the lawn. So that's good. But nitrogen is nitrogen, whether it's organic, or it's nitrate, or ammonium, eventually, it gets broken down and becomes usable by that coastal ocean. So when we're looking at trying to reduce nitrogen to our coastal systems, it's not just switching to organic fertilizer, it's also using less fertilizer, because it's that quantity that matters.
Jeff Berckes (17:18):
So there's another aspect of this as well. Right? So then, so nitrate has a drinking water standard, what can you tell us about that?
Jamie Vaudrey (17:24):
Nitrates getting into our drinking water is one of those water quality issues that we think about on the land. In certain places, the the nitrate levels have been so high that it causes something called Blue Baby Syndrome, where literally, it's impacting young, young infants abilities to take in oxygen, so they look like they're oxygen deprived. I don't know if that's still, still happening right now. Because now with our freshwater processing, you know, we're in places where that is likely to happen. People are more aware of it with well water testing, and are using alternate sources of water. But that's just one example of the impact that nitrogen in our freshwater can have on us on its own nitrogen is generally not harmful to us as human beings like we can drink nitrogen with rich water for the most part, and be fine. What happens though, is that as that nitrogen is in our water, it can start to impact things like allowing bacteria to grow more robustly, we get we get more bacterial growth in a system. It also has an impact on freshwater lakes. You know, in the freshwater lakes, we are often talking about phosphorus is that limiting nutrient. But if you add a little nitrogen with that phosphorus, it can make that lake system much more productive. Similar to on the coastal ocean. Yes, we care about nitrogen. But if you have nitrogen and some phosphorus, it grows, those plants will grow even more robustly, they'll grow more aggressively than if you have just nitrogen alone. So looking at that balance is also important.
Jeff Berckes (19:10):
All right. So where does this stuff come from? And what are some of the practices that help try to remove this from the environment?
Jamie Vaudrey (19:18):
Yeah, so that's a great question. Nitrogen comes from three main sources. We have the nitrogen that comes from our waste. We are We are humans, we live on the land, we eat, and we excrete, and we are nitrogen recyclers, we are nutrient recyclers. So we're taking in nutrients, living and putting nutrients out. Since the 1970s. We have recognized that that nutrients are an issue. And over time, our ability to handle our wastewater has improved. You know, first, we started by just removing the things that were going to cause bacterial problems. Nowadays we're into nitrogen-removing sewer systems and nitrogen-removing septic systems. And what that is doing is it stripping the nitrogen out of our waste products, and putting it into other forms often into turning it into a gas, which goes into the air and is the inert, meaning that it's not, it's not accessible to plants once it's nitrogen gas, or locking it into solid form. So the nitrogen-removing septic systems do that in a couple of different ways. But one of the ways that we can remove nitrogen is by literally putting a type of wood chip in the ground. And so as the freshwater flows through this bed of woodchips, the bacteria that are living in those woodchips are taking up that nitrogen and locking it into biomass that's under that's underground. So being supportive of these initiatives to upgrade wastewater treatment plants to remove nitrogen is really critical. We've seen a big improvement in Long Island Sound from from this nitrogen reduction strategy to improve our sewer systems, to remove that nitrogen. We kind of reached a plateau in our ability to remove nitrogen from our sewer systems. And we've done all that we can do right now, that's not quite true, we haven't done all that we can do. But we've done a lot of what we can do. And so the attention is really focused to what we call nonpoint sources. So if you think of a point source, that's our sewer treatment plant, you can literally point to a pipe and say that's where the nitrogen is coming from the nonpoint sources are much harder to go after. Because they're things like your individual septic system that's at your house treating your wastewater, or it's the fertilizer that you're applying to your lawn, or that the farmer is applying to their field. The third source of nitrogen that we get, the third source of nitrogen is from atmospheric deposition. And that's basically the rain and the dust that settle onto the land. And that includes nitrogen in it. So when you're when you catch a handful of rainfall, it's fairly well loaded with nitrogen. Again, it's gotten better over time, with the advent of the Clean Air Act, we are seeing reductions in the pollutants that are in our rain. But, but we do still get that fertilizing impact of rain, snow and dust from atmospheric deposition. So you asked how do we how do we treat it? How do we fix it? You know, first of all, you have to identify the sources. So those are our three sources, the fertilizer, the human waste, and the atmospheric deposition. There are natural sources of nitrogen. But the issue is not those natural sources. It's it's what we as humans are doing that's having an impact on that coastal water quality. So we want to go after those humans sourced those human sources. on kind of a society level, those big infrastructure improvements to our sewer systems are important. But on a personal level, we can reduce our nitrogen in many different ways, including reducing the amount of fertilizer that we're using. We often when we're trying to get communities to reduce their fertilizer, we have a few basic guidelines, you know, you want to fertilize your lawn when your lawn is growing. And so that means that it when when your lawn goes dormant in the middle of summer, which happens here in Connecticut, don't fertilize your lawn. When it's the middle of winter. don't fertilize your lawn, the grass is not growing, it cannot take up that nitrogen. So fertilize when you're when your lawn is growing. And that's usually around Memorial Day or Labor Day. A big one though, is if you like the way your lawn looks, don't do anything. If you like the way your lawn looks, it means it has enough nitrogen, it has the right, the right conditions, it's happy. You don't need to continually add nitrogen to it. An established lawn needs relatively little nitrogen, so stop the nitrogen use on your lawns. But I tell people you know, yes, we are water quality may be relatively poor here because we've got nitrogen coming into the system, but often it's swimmable, often it's fishable. So it's a, it's a, the environment needs a much higher level of purity or quality than we do as humans. And that's that's part of the problem. You know, if it were physically harming us to have this poor water quality, I think that there would be a lot more action taken a lot more immediacy, a lot more urgency. People would care more if going in the water was harmful to us. But it's not harmful to us. It's just harmful to the blue fish and the crabs
Jeff Berckes (24:58):
which of course can be harmful to us. In the long run, because that costs us more to harvest and eat those good things that we like to eat. But, Jamie, I really want to thank you so much for your time. And thank you for joining us and sharing your expertise on the clean water pot.
Jamie Vaudrey (25:11):
Well, thank you for your interest.
Jeff Berckes (25:20):
Okay, that was my interview with Jamie Vaudrey, from Connecticut. We're going to shift over now to talk to James Cotner, from the University of Minnesota about phosphorus.
And I'm pleased to welcome Jim Cotner to the Clean Water pod. Jim, welcome.
Jim Cotner (25:40):
Thank you. It's great to be here.
Jeff Berckes (25:42):
All right, well, really excited to dive into this topic of nutrients. But before we get going, I want to know, where are you from? Where did you go to school? And why the heck did you choose water quality is what you did with your life?
Jim Cotner (25:55):
Great question. So I grew up in the Midwest, but not in Minnesota. I grew up in Ohio. I, I basically imprinted on water. As a kid, I came from a family of swimmers, but I also imprinted early on in the Great Lakes. I basically went fishing with my grandfather, and that, that meant a lot to me. And I think that's one of the reasons I just love being around the water.
Jeff Berckes (26:27):
So let's talk about phosphorus. And I want to talk about this concept of, it's a nutrient. So let's start there. Because I think a lot of people hear nutrients and they think that's good. We need nutrients to live nutrients are a good thing. But when we talk about water quality, we so very quickly get into nutrients being a bad thing. So why don't we just kind of establish what the nutrients are, and why they're present and how they're good for water quality, but then in excess can be bad. So let's let's just start with the the concept of nutrients. Yeah, so
Jim Cotner (27:01):
there are lots of different nutrients that we need in order to make cells or biomass. And we talk about in water quality, we talk about macronutrients and micronutrients. So macronutrients are things like carbon, nitrogen, and phosphorus, oxygen, hydrogen. So these are the things that we need the most in our cells. And micronutrients are things like molybdenum, or iron, or cobalt, things that we need in order to make cells, but we need a lot less of them. And so nitrogen and phosphorus are macronutrients. But they're also nutrients that are very commonly limiting in freshwater and marine ecosystems.
Jeff Berckes (28:04):
Alright, what do you mean by limiting? What does that mean specifically?
Jim Cotner (28:09):
Great question. So limiting means that, you know, if you're going to put a cell together, you need all those things carbon, nitrogen, phosphorus, oxygen, hydrogen, sulfur, you need them in a certain ratio, okay? You don't need as much phosphorus as you need carbon. And you don't need as much nitrogen as you need carbon. But you need all of those things in order to make proteins and cells. And if one of those is missing, or available at lower concentrations than what you need it as, then it will be limiting. And the way I explain this in my classes is, it's, it's sort of like an assembly line, you know, you're putting together a vehicle and you need a certain number of wheels, you need a certain number of axles, you need a certain number of transmissions, and so on and so forth. That number is different depending on what part you're looking at, right? But if, if one of those parts isn't being produced at you know, the factory that supplies the assembly line, at a high enough rate, it becomes limiting. So let's say axles are produced at a different factory. And that factory goes on strike well axles become a limiting process in terms of how many cars you can make, and it's the same idea with cells. So if, if you need phosphorus at a certain level, and it's low relative to everything else, it becomes limiting to the production of cells.
Jeff Berckes (30:13):
Okay, so when we talk about water quality, let's talk about the good aspect of what presence of phosphorus can bring. Right? So there because there is a positive here, again, it's a nutrient. So what does it provide in the positive aspects?
Jim Cotner (30:29):
Well, essentially, many of our freshwaters, because they are phosphorus limited when you have phosphorus available for the cells. For, you know, for algae and bacteria, and the plants that are growing in that system. When there's plenty of phosphorus, they can grow, essentially, to a very significant extent, I'm not going to say, to an unlimited extent, because other things become limiting. If you add more phosphorus, for instance, if you're an Alga that's growing in the water column of a lake, and you add phosphorus, and that system is phosphorus limited, you're gonna get more and more algae and, but eventually, the algae attenuates the light that's in the lake. So it blocks out the light. So that light becomes limiting. And similarly, if light doesn't become limiting, perhaps something like nitrogen or carbon becomes limiting. So eventually, all those things have to balance in order for you to get unlimited growth, basically. What we want in a balanced, what we want is a balanced system, essentially. So if you have nitrogen and phosphorus and carbon, at a steady state, where they don't accumulate to any significant extent, that's when everybody the whole ecosystem is happiest, right? But when they get out of balance is when you get excessive growth. And excessive growth is problematic, because when all those algae decompose, they lead to low oxygen, or even no oxygen conditions in the bottom of the lake, or a river or a pond. And those low, or no oxygen conditions are not good for everybody, essentially, that's living in that ecosystem, except for bacteria. And we can't eat bacteria. We want to eat fish. And so essentially, what we want is a balanced ecosystem, where nitrogen phosphorus are not in excess, relative to the needs of the algae, and the organisms that eat the algae.
Jeff Berckes (33:14):
This might be a silly question, Jim. But fish breathe underwater, right? Like that's, I think that's something that we maybe just kind of need to establish that the you know, the the fish that are in the, in the water in the lakes that we're trying to grab with our fishing poles, they need something called dissolved oxygen to survive. And the amount of algae, like you're saying, can really complicate things if there's too much as it dies back. So can you maybe talk a little bit about that?
Jim Cotner (33:44):
Sure. So yeah, as you mentioned, Jeff, there's a certain amount of oxygen that's dissolved in the water, and that's a function of two things. The first thing is it's in equilibrium with the atmosphere. So there's, about 20% of our atmosphere is oxygen. And so it's sort of, you know, like a can of soda. So if you put a bunch of co2 in a can of soda, it's gonna dissolve into the Can of soda and that's what carbonates are Can of soda. So there's oxygen in the atmosphere that is oxygenating the water, okay. And lots of organisms depend on that oxygen in order to metabolize. So fish are just like us. So they, they consume oxygen and produce co2 through their metabolism. And the way they get oxygen is from that dissolved oxygen in the water, it absorbs they absorb the oxygen across the gills, basically, and it goes into their bloodstream that way. But another way ironically, that oxygen gets into the water is through photosynthesis from plants. So remember, we were talking about algal blooms. So an algal bloom. When those algae are photosynthesizing, they produce oxygen as a waste of photosynthesis. And that helps increase the amount of oxygen in the water. But when those algae decompose, that's when that oxygen gets consumed. And one of the things that happens, particularly in lakes and ponds, is that the algae are photosynthesizing and producing excess oxygen at the surface. And then they fall to the bottom of the lake or the bottom of the pond, where the oxygen is consumed through decomposition, mostly bacteria that are consuming them. And when that happens, the oxygen disappears. And, you know, if you're a fish, and you don't live at the surface, where the oxygen concentrations are going to be higher, that can be problematic, of course.
Jeff Berckes (36:09):
So one of the things that an algo Blum can do to a fishery is lead to something called a fish kill, which is something that we see in our impaired waters list, one of the episodes that we had last year where we focused on impaired waters lists, one of the things that you might see on an impaired waters list in the state you live, is something called a fish kill. So do you know much about that concept? And what leads to that? And sort of what? Basically what happened there, right, is that an algae bloom leading to a fish kill, and the overall health of the fishery?
Jim Cotner (36:46):
Yeah, so fish kills are becoming more common actually, across the US and actually globally. And there's a number of factors there, one of the biggest ones, obviously, are algal blooms. And so as I mentioned, those algal blooms lead to the accumulation of organic matter or algal biomass. And when that falls to the bottom, it can consume all of the oxygen and make it such that the fish can't survive. So, you know, there are certain fish that live in deeper water. In Minnesota, you know, some of those fish are ones that we like to catch like walleye, or lake trout. And those fish are particularly susceptible to this phenomenon. So when the algae falls to the bottom, they're going to decompose consume the oxygen and potentially kill those fish off, because they can't go to the surface because the water is too hot for them there.
Jeff Berckes (37:51):
Basically if you get these conditions where you have too much phosphorus, and you get too much algae, you get algae blooms, or just get too much algae, it can lead to, you know, an ungainly appearance, right? There's some it's not a lake that you're going to want to be around may have a smell to it, right? It's not going to look very pretty, it's certainly not something that you're going to want to wade into if there's a beach, on that lake or anything like that, right. So there's, there's some human components there that you may not be interested in from an aesthetic standpoint. But from the fisheries standpoint, that really ties into a lot of tourism, or even just that enjoyment for that local community around that lake that likes to use that as a fishing resource. And if you don't have the right water quality, if if the water quality is suffering, because of those inputs, you're not going to be able to grow those sport fish that you want to catch the fisheries really going to change, right, you're just going to have, you know, rough fish or things that maybe aren't as fun to catch.
Jim Cotner (38:56):
Exactly. So a lot of the rough fish are better able to deal with low oxygen conditions. Basically, there are some of those rough fish, they have hemoglobin that's different. So it can hold on to oxygen more effectively. And some of them actually are able to gulp air from the atmosphere. But those fish are usually not the ones we want to catch. The ones we want to catch are more susceptible, and climate change is in addition to increased nutrients coming from the landscape, climate change is feeding into this problem as well. And the way climate change matters is that when if you swim in a lake in the summertime, you can tell that there's a temperature difference from the surface to the bottom so you dive down and you can tell it's colder at the bottom. That cold water at the bottom is where cold water fish like walleye and lake trout reside, the cold water actually holds more oxygen. But the problem is that climate change is making it so that you have those stratified conditions where the surface water sits on top of the bottom water for a longer period of time. So it's sort of like the fish are in this enclosed mass of water with no exchange with the atmosphere. So there's no new oxygen coming into that system. And with climate change, lakes are staying in that summer stratified state for longer periods of time. And what that means is the oxygen that's in the bottom of the lake is being depleted for longer periods of time and making the habitat for the fish that live down there more vulnerable.
Jeff Berckes (41:04):
When we talk about phosphorus. And we mentioned a little bit particularly in the Midwest, we talked about fertilizers. What are the sources of phosphorus, do you have like a somewhat comprehensive list of where this is coming from, and how this is entering our waters?
Jim Cotner (41:20):
Well, Phosphorus is in all living organisms, okay. So it makes up about anywhere from one to 3% of all of us, you know, from microbes to elephants, basically, that's where a lot of it comes from. And so, in aquatic systems, as we talked about, a lot of the nitrogen and phosphorus is just coming from organisms that are already in the lake that are decomposing. Okay. So that's a major source. But when we tend to get excessive algal blooms, we also have phosphorus coming in from the surrounding landscape at relatively high rates. And that can be from decomposition of organisms in the upstream region. But increasingly, it's probably problematic in that it's coming from fertilizer use. And we do a great job of growing things. In the Upper Midwest, we have great soils, we have flat landscape, which makes for excellent conditions for farming. But in order to maintain the ideal conditions for farming in the Upper Midwest, we add phosphorus to the landscape in the form of fertilizer. But as we mentioned, that fertilizer doesn't all end up in the crops that we harvest. And that's where the problem comes from. So if it stayed, if it all went into the crops, we wouldn't have a problem. A bunch of it runs off into the surrounding aquatic systems. One of the things we haven't talked about that I should make everybody aware of is the fact that this whole phenomenon can lead to positive feedbacks. So and what I mean by a positive feedback is that if you add more phosphorus, it tends to accelerate the eutrophication process. So think of it this way. So we add phosphorus on the landscape that runs off into a lake. It leads to an algal bloom that occurs in the lake, the algae grow, they die, they fall to the bottom, and they decompose. Those low oxygen conditions are a result of decomposition also make it so more phosphorus comes out of the sediments and back into the water column. That's called internal phosphorus loading. So you think of all the organisms that have lived in that lake, over decades to millennia, they fall to the bottom, most of them decompose and release nutrients back into the water, but a lot of them just don't completely decompose. So a lot of the phosphorus stays in the sediments. Those low oxygen conditions actually make it easier for the phosphorus to migrate out of the sediments and into the water column.
Jeff Berckes (44:46):
So basically, what you're saying is that you have a faucet that's on that has that's bringing in a certain amount of phosphorus every year because of excess fertilizer or maybe a failing septic systems up in the watershed. How ever its getting into the into the water, there's a faucet coming in. And every year, whatever is coming in certain amount of that is going to just settle at the bottom of the lake and not leave the lake. And then every year, you get a little bit more kind of a bio accumulation of some kind in that lake. So as we move forward, it's more likely that we're going to get future algal blooms because of that influence of the faucet on.
Jim Cotner (45:29):
Yes, that's exactly right. And a critical turning point is when the sediments become anaerobic. So there's, there's no oxygen left. And so most lakes go through a cycle, you know, over their lifespan, where initially they're deep, and oxygen concentrations are high throughout the lake. But as lakes get more productive, you know, if there's more algal blooms, basically, there's more algae that fall to the bottom, consume the oxygen and lead to this acceleration process. The other thing that's important about that is that as that material falls to the bottom of the lake, it continues to get shallower and shallower over its lifespan. And what that means is more of those nutrients are closer to the surface of the lake where the algae are able to grow. So it's like you're you're bringing the nutrients closer to where they're, they're being used by the algae, and it's all just accelerating.
Jeff Berckes (46:47):
Okay, so now let's talk about how we fix this. Right. So two questions, one, how do we turn off that faucet, which the input that is coming in from the rest of the watershed? And then the second part of that is, once you maybe get that faucet turned down, or, or turned off to a reasonable extent, how do you clean up the lake itself?
Jim Cotner (47:09):
Great questions. There, those are difficult questions. If they were easy questions, we would have fixed them by now, but they're not. And so the main, the main way to start to fix the process is to eliminate or at least attenuate the sources of those nutrients. And we've done a lot of great things along those lines in the US. Okay. So one of the things we realized back in the 50s and 60s is that phosphorus was a problem. And we first started to notice this in a few fairly large Lakes, Lake Erie is sort of the poster child for this. So back in the 50s, and 60s, they noticed that these low oxygen conditions were leading to a die off of insects, which were important feed for a lot of the fish in Lake Erie, okay. And so, and they, when they realized that phosphorus was a big problem, one of the first things they did was they did a much better job of removing phosphorus in sewage. So, as we've have talked about phosphorus is in all organisms, including us. And so our waste is full of phosphorus. And so when we flush the toilet, we're sending a lot of phosphorus to the sewage treatment plant. And so sewage treatment plants in the 70s 80s and 90s got really good at removing phosphorus. And they do that a number of different ways. One of the big ways is just to pull as many particles out of the water as possible, because phosphorus is not very soluble. And so if you can get rid of the particles in the water, you can get rid of a lot of phosphorus. But another thing that they do at sewage treatment plants is a lot of sewage treatment plants will treat the water with alum or ferric iron. And those chemicals react with phosphorus and remove it from the water and put it into a particulate form which you can filter. Okay. And so if you do that you can remove upwards of 90% of the phosphorus that's coming into a sewage treatment plant. It's a little bit more problematic on landscapes, but the principles are the same. So And as we mentioned, a lot of the phosphorus, on landscapes in agricultural settings in particular is in particulate form. One of the ways we try to keep phosphorus out of aquatic systems is by putting buffer strips around aquatic systems or around farmed systems, until a buffer strip is just a strip of land, where you have plants that grow and thrive, when you present them with lots of nutrients. So, you know, it can be wetlands, it can be forested systems, basically systems that are able to thrive on the nutrients, and remove them, and put them into their own biomass before it gets into the aquatic system, where it can do a lot of harm. So there are a lot of best management practices that are essentially focused on exactly that. Okay. Finally, the last thing that you can do is remove the nutrients once they're in the lake, or in the river, or in the pond. And, again, essentially what that comes down to, there's different ways of doing that. But one of them is just similar to what you do in a sewage treatment plant, you just add iron, or aluminum as hydro- in the hydroxide form. And that will bind the phosphorus and pull it down into the sediments. And it's bound in such a way that it won't be released, if the water column becomes anoxic or no oxygen left in it. In many lakes in the Upper Midwest, one of the practices that is commonly used is a harvester. And so a harvester is just a large contraption to cut the plants that are growing from the sediments. So, you know, milfoil is, is one of those coontail is another one that's commonly harvested. And so basically, it's they cut the plants, they have a little conveyor belt that pulls the plants up from the bottom of the lake and just puts it into a big bin. And then that bin is removed from the lake. And so as we said, there's lots of nitrogen and phosphorus in those plants. So when you remove the plants, you're removing those nutrients. The last thing that is commonly used in a lot of lakes is is just to artificially add oxygen into the lake. And so many of us are familiar with lakes, you'll that you'll see bubbling, especially in the wintertime in the Upper Midwest, so they're just adding oxygen to the lake. And that does two things. It provides habitat for the fish that require the oxygen. But it also makes it so that the phosphorus that's in those sediments of those lakes, is more likely to stay in the sediments rather than come to the surface where the algae can use it.
Jeff Berckes (53:29):
Well, it seems to me like you talked about putting oxygenation, contraptions inside of lakes, that seems like a bit of a treatment type, they may not even treatments the right thing, but just kind of like life support. So you know, to cover yourself over the winter months, you know, you talked a little bit about treating with with with an alum with, you know, with an aluminum or an iron to try to capture that at the bottom, you know, that seems like treatment of the symptom a little bit. Whereas the harvesting of the plant matter, then you're over time you're removing that phosphorus from the system. So I would think that that would be more of a long term fight that would eventually get you better results. How long do you typically see that kind of approach take until you really start to see some significant differences?
Jim Cotner (54:28):
Well, that's a great question, but a lot of it depends on the lake that you're working in. And how bad it is. You know, I will say that the most appropriate strategy is to start in the watershed. So those best management practices or you know, like removing nutrients via sewage treatment, or best management practice says before it gets into the lake, that's the best way. Okay, in an ideal strategy, what you what you would do is start there. And then potentially, you know, something like harvesting would be another strategy for removing nutrients once they're in the lake. And that one is fairly straightforward. But it's also not cheap. And then alum is a is a treatment as more and more commonly being used in lakes as well. So you have basically those, those three major levels, but you have to start in the watershed. And if you do that in, in combination with something like harvesting, you know, in a smaller lake, you're gonna see effects on relatively short term. I mean, the harvesting, you see the effects, you know, very quickly. But it might take on the order of years to decades before, the combination of those two processes leads to significant results in the behavior of that system. But a lot of it depends on how big the system is, you know, the bigger the lake and the further along you are in the eutrophication process, the longer it's going to take. It's sort of like inertia, and you have to overcome that inertia in orders sort of set the clock backwards in terms of nutrient management.
Jeff Berckes (56:41):
Well, Jim, I really appreciate your time and your expertise and for coming on to the Clean Water pod to share that with us.
Jim Cotner (56:48):
Well, it's been an excellent experience for me, and I love talking about phosphorus. So happy to do it.
Jeff Berckes (56:58):
All right, that is our first episode of season two. I hope you all enjoyed this kickoff episode. Please join us next month for Episode Two as we dive into success stories associated with nutrients in our nation's waters. If you have any questions about this or future episodes, please get in touch. You can find us on Twitter at cleanwaterpod or send me an email at cleanwaterpod@gmail.com. We'd love to hear from you, what questions you have, and what you'd like to hear on the pod. Until next time. Thanks for listening
Popular Podcasts
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
The Joe Rogan Experience
The official podcast of comedian Joe Rogan.
24/7 News: The Latest
The latest news in 4 minutes updated every hour, every day.