9UNP0140SD_Harvey Bootsma_WordPress

- I've been doing aquatic science for a number of years. And every once in a while, we get opportunities to speak to the public and often the attendance is fairly low. But I have discovered over the last year or so, that if you really work on an issue like stinky algae, you do get much better attendance for your talk. 
(laughter)
 And it's gratifying. Thanks for your invitation to speak. The title of the talk is, "Nuisance Algae in Lake Michigan, and What Makes It Grow." What you'd probably rather see for the title is what makes it not grow, because that's really one of our objectives. But I think by understanding what makes the nuisance algae grow in Lake Michigan, we can also get at the issue of how we might be able to reduce that growth and make the problem a little bit more tolerable. 

(inaudible)
 Can everyone hear me okay? Is this volume okay? As most of you know, there's a number of problems associated with Cladophora. The one that most people are aware of is the aesthetic problem. Here's an example here, closer to Milwaukee, it looks terrible and once it starts rotting, it smells terrible. There's other problems associated with it as well. It can clog water intakes, a number of power plants, both here on Lake Michigan and other parts of the Great Lakes have actually had to be shut down because of having their water intakes clogged with Cladophora. And we're also starting to see botulism in the Great Lakes. It's been in Lake Erie for a number of years. 

It's starting to become a problem in some parts of Lake Michigan now. We're not sure, but the hypothesis is that it's ultimately linked to Cladophora, which can promote anoxic conditions in the sediment, which promotes the production of the botulism bacteria. And it's also a nuisance when you go dive, because stuff tends to get snagged up. When we started looking a number of years ago at the Cladophora problem, we said, well, let's look at what Cladophora needs to grow, and look at the history of those environmental factors and see if we can figure out what has changed over the last 10-15 years that may be causing the excess Cladophora that we're seeing now. So if we consider what Cladophora needs to grow, it needs a hard substrate. And on this side of the lake in Wisconsin, we're either blessed or cursed, whichever way you want to look at it, with lots of rocky bottoms. The Michigan side of the lake doesn't have nearly as much, and therefore Cladophora isn't nearly as big a problem there. You need nutrients. And in Lake Michigan, there's excess of all nutrients except phosphorous. Phosphorous is at very low concentrations in Lake Michigan, so that's the nutrient that controls the growth of most algae in Lake Michigan. 

And like for any plant, you need light. Then the optimum temperature, which for the Cladophora is in the 13-17 degrees Celsius range. So our research started by looking at these factors in Lake Michigan, and how they currently control Cladophora, and how they may have changed in the past. So two key questions that are, what are the roles of nutrients, light and temperature in controlling Cladophora growth; and how have those changed in the last 10-15 years in a way that may have caused the increase that we're now seeing. And the way we did this, was we did research both in the lake and in the laboratory. In the lake, we did a lot of monitoring of those conditions, light, temperature, nutrients, and monitoring of Cladophora itself, to see how Cladophora nutrient status and Cladophora growth changed in time in relation to these variables. And one thing we were trying to do is to develop a model that links Cladophora growth to those variables of phosphorous loading, and light and temperature. This is a conceptual diagram of the model. Those three variables determine the dissolved phosphorous concentration in the lake, which then becomes stored phosphorous within the Cladophora algae itself. And that, combined with light and temperature ultimately determine the growth and the biomass of the Cladophora in the lake. 

Now this is a model that a professor at Michigan Tech developed for Lake Huron back in the 1980s, when Cladophora was a problem there. We're taking that model now, and trying to make it work for Lake Michigan working with that professor who's still at Michigan Tech. One difference is that when this difference was first developed, there were no mussels in the Great Lakes. And now we have lots of mussels. And mussels may influence this model, because they are a source of phosphorous. Mussels eat the plankton, and then they excrete the phosphorous, which in turn can become available for Cladophora. Mussels and Cladophora live in the same habitat, in the near shore area, on the hard, rocky bottom. So they live in close proximity to each other. So what we're trying to do now is incorporate this into the model to see how mussels are also potentially influencing Cladophora production in the lake. Now here's an example of a model. 

This is the front face of the model. There's a number of places where you provide input to the model, temperature, light, dissolved nutrients, and so forth. And then this is the front of the model, where you provide a few variables here. And then you can run the model, and it provides graphic output here. And you may have trouble reading this from the back. But this is the key graph we like to focus on. This is biomass Cladophora and this is --. This is running right now from around early June, up until late September or October. These points you see here are actual measurements in the lake. We go out into Lake Michigan. 

We measure the biomass of Cladophora. So we're comparing those points to what the model is telling us should be out in the lake based on light, temperature and nutrients. And you can see that, through this growth phase from May until around the end of July, the model does fairly well. There's not a lot here, but the general increment in Cladophora is simulated fairly well by the model. Later on in the summer, the model doesn't do so well. This is what we call a sloughing phase. The Cladophora's breaking off now. This is a problem time, when it's coming up on shore. It's breaking off. The model doesn't really account for that breaking off, because we still don't really understand the processes that cause the Cladophora to break off. 

But if you think about it from a management perspective this is stuff that's breaking off, because it's growing out in the lake. If we want to manage Cladophora, we should be looking at this part here, because we want to stop the growth of Cladophora in the first place. And in that growth phase, the model is doing fairly well. So right now, at least for the conditions under which we calibrate the model, it seems to simulate growth pretty well, so we can start using it to look at these different factors and see how they control growth in the lake. Well, first we look at the role of temperature. If we look at the history of temperature in the near shore of Lake Michigan, this is what we've seen over the last 35 years. This is just the June to August average temperature, so summer temperatures. There's a lot of noise in here. But in general, the temperature has been increasing over the last several decades. I won't go into all the details for why that's occurring now. 

It's not so much global warming, as it is a change in wind directions over Lake Michigan. The question is, could this be responsible for an increase of Cladophora in the lake. So if we use the model, and we put some different temperatures in the model, this is what we find. At 5 degrees, 10 degrees, 15 degrees Celsius, the model is over a 200-day period and we see biomass increasing. But at all those temperatures, the maximum biomass is roughly the same. And when we start to get warmer temperatures like 20 degrees and 25 degrees, which is essentially room temperature, we actually see biomass coming down. And that's because at those warmer temperatures Cladophora respires more. And it respires more than the photosynthesizing, so it burns itself out. The Cladophora does best at cooler temperatures, but we're seeing this shift in Lake Michigan from an average temperature of around 8 or 9 in the summer to maybe around 12 now. And what this is suggesting is that within that range, that temperature change probably isn't causing a lot of the change that we're seeing in Cladophora. 

So we don't think, even though the near shores are warming up, we don't think that's playing a big role in the Cladophora problem right now. What if we look at the light, the history of light. Well, here's light at a depth of nine meters in Lake Michigan. This is in the summer of 2006. This dashed lined here is the line that is the threshold for Cladophora. If you're below that, Cladophora has a tough time growing. If you're above that, it's happy. And what we can see at nine meters is that in July, you're border line. As we get into August, September, we have sufficient light for Cladophora to keep growing. This is again at a depth, I think it's actually nine meters where we had this light meter. 

It can grow down to 10 meters, or a little bit deeper than ten meters. If we look at the history of light in Lake Michigan. This is the history of a disk that we put into the water and you just drop it till you can't see it anymore. And so the deeper the depth, the clearer the lake is. This is data collected over the last 12 years. And back in the early 1990, the disk depth was around three meters. That's steadily increased over the last decade and a half, and this is going up to 2002. This trend has increased so that water clarity now is about three times as much as it was back in the early 1990s. One reason is the mussels. We had the zebra mussels coming in in the early 1990s. 

Mussels are great filtering machines. They pull all plankton and particulate material out of the water column, thereby clearing up the water. So the water is much clearer now than it used to be, thanks to the zebra mussels. And now quagga mussels, which have largely replaced zebra mussels. Here's just an example of that. This is just some water that I took from Milwaukee harbor. I stuck it in two bottles. In one, there are zebra mussels. I let it sit for 30 minutes, and took another picture. And you can see here this jar has cleared up a little bit, but you can see how clear the water has gotten in this jar. 

That's because the mussels here just filter the all of that stuff out of there. And they're doing the same thing in the lake. So if we back track, and we take that water clarity back from the early 1990s and plug it into, basically we take 2006 data, and say how much of that light in 1991 would have gotten to the bottom of the lake at nine meters. This is what we see. Here's 2000, sorry, this is 2004. This is 1991. In 1991, we would never have had enough light at nine meters for Cladophora to grow. But you do in 2004, because the lake has cleared up. So it looks like light is potentially important factor responsible for the increasing Cladophora that we've seen. What if we look at the third factor, which is phosphorous. 

This is total phosphorous concentrations in Lake Michigan. This is from the EPA monitoring program. This is from 1983-2005. And a slow decline over time. The target set for Lake Michigan for total phosphorous concentrations set by the Great Lakes Water Quality Agreement is seven micrograms per meter. And we're well below that now. This is for open waters in Lake Michigan. So we've met the conditions of that target, and yet we still have this Cladophora problem near shore. If we look in the near shore area, which is not the same as the offshore, here's some data that I collected. I got it from MMSD, who has been monitoring near shore around Milwaukee for a number of years. 

What you see here is that it was actually declining near shore up until the '90s, but in the last five to ten years, there's been quite an increase in the near shore concentrations of phosphorous. The near shore, at least now, looks like it's a little bit above that Great Lakes Water Quality Agreement. So the targets have been met for offshore waters, but it looks like they're still exceeded at least some of the time for near shore waters. So the question is, is that increase in phosphorous in the near shore potentially contributing to the Cladophora problem that we're seeing now. Now we have this history of light. We know the temperature change over time. And we have data on phosphorous change over time. We can plug that data into that Cladophora model I showed you earlier to determine how those three factors work together to change Cladophora over time. So this is using conditions from pre-mussel era, from the late 1980s, using phosphorous, temperature and light from that era. Then we say, let's put in this increased dissolved phosphorous I've just showed you, and see what that would do to the Cladophora biomass. 

It raises this a little bit, but not a lot. What if we just take the post-mussel water clarity, so this is like 2006 water clarity, and put that into the model, but keep everything else the same as it was before the mussels. Now we see Cladophora abundance really shooting up. So it looks like light is having a much stronger influence than phosphorous alone. When we put the two together, this is what we get. So now we're getting three times as much Cladophora as we were pre-mussels, due to this combined effect of greater water clarity and increased phosphorous concentration in water. Now the next question is, can we manage this? Can we do anything about this? Well we can't do a lot about water clarity unless somebody's willing to fly over the lake every weekend and dump a lot of dirt or something in the lake. It's not really a feasible option. 

Really, it's the only option. We can't do much about temperature. The only option we have is to look at phosphorous. And that's how the lake has been managed for the last several decades. So if you go back to the model. And what we want to do is to try to get this line here to flat line. We'd like to see no increase in Cladophora over the summer. Well, one thing you can do in the model is that there is a phosphorous multiplier here. And we can change that so that it takes all the input data that we provided and multiplied it by that number. So it allows us just to theoretically reduce the phosphorous concentration and see what would happen to the Cladophora biomass. 

So here we've run it at 1.0, using real data for 2006. We can reduce that to .75 to see what it does to Cladophora biomass. What you see is that it starts to come down, but it still does continue to grow. Now remember this is all at a depth of nine meters, because that's where we collected most of our data for. Now if we reduce this to .5, that's the point where, at least at nine meters, we see biomass flat line. There's no growth or increase in Cladophora over the summer, because phosphorous is too low for it to grow very much. So at nine meters, if we reduce phosphorous by 50%, we could pretty well stop the growth of Cladophora at nine meters. But you have to look at the whole near shore area. Cladophora grows from close to shore to a depth of about 11 and 12 meters. And we have to consider that whole zone when we're thinking about how Cladophora is going to respond to changes in phosphorous. 

So here is a graph from two meters down to 10 meters, of how Cladophora would change in response to these reductions in phosphorous. So here's 100% of this 2006 data. Here's 75%, 50% and 25%. If we look just at our reference depth of nine meters, here's what we're calling the preferred Cladophora abundance. Now this is not, we haven't put a lot of work into saying what's the ideal Cladophora biomass. But this is a number the Michigan Tech professor chose when he was doing work on Lake Huron back in the 1980s. And so if we use that for now. He said 50 grams per square meter would be a nice target to shoot for. Well, at nine meters, if we were to reduce phosphorous concentration by 50%, we get down to that level. You can see at shallower depths, even if you reduce by 50%, this will still be well above that level. 

In other words, one thing to remember here about models. A famous statistician who started at England and actually finished his career at UW Madison, he said all models are wrong, some models are useful. The reason for that is no mathematical model can ever really account for the complexity of the natural environment. There's a lot of things going on out there that may influence Cladophora growth, but we don't include them in the model, because it's just too difficult to account for everything. And so we have to be careful when we use these models to look into the future, or to understand Cladophora ecology. And one example is looking at this depth distribution of Cladophora that is put out by the model. In reality, we may see something like this. Because as you get into shallower waters, there's more wave action. There's more turbulence. This Cladophora is broken off the rocks more frequently. 

That doesn't happen out at these depths, but it may at these depths. And some evidence for that is a few years ago, we did depth profiles of Cladophora in the lake. Here's a depth of ten meters, which is close to our model depth. Here's five meters. The model says we should have a lot more biomass at five meters. But in fact, we didn't. It was almost the same as ten meters. That's somewhat encouraging, because then if we go back to what I just showed you, maybe the results that we're seeing here, as a result of phosphorous reductions, maybe we also see them at shallower depths, as well. But we have to do a bit more work at shallower depths to see how well this model will work at shallower depths right now. But that's just a precautionary note, that you always have to be careful using these models. 

Nothing beats real data from the environment. So now, we've looked at some possible effects of reducing phosphorous. If we want to reduce phosphorous in the lake, then we have to ask ourselves, where is it coming from? Could we actually reduce phosphorous concentrations in Lake Michigan. There's a few possible sources. It may be coming from rivers, from the land being washed into the lake. Or within the lake, you've got the mussels. Mussels are eating particular phosphorous in the form of plankton and other particulate. And a lot of that is excreted out as dissolved phosphorous, which is the form that Cladophora needs. Mussels also may be providing the phosphorous that's needed for Cladophora growth. 

So what we did was say, let's take these rates for a certain stretch of Lake Michigan. Let's take the stretch between Fox Point and Wind Point, and let's look at the phosphorous excretion by mussels in that area. Let's look at the uptake of phosphorous by Cladophora in that area to see how it balances. Let's also look at the phosphorous input from the river and compare those three numbers to see what's the most important. Cladophora uptake, we estimated that around 119 milligrams of phosphorous per square meter. The river input is around the same number. Theoretically, there's enough coming from the river to support this, but the Cladophora isn't 100% efficient. It's not going to grab all of the phosphorous coming into the river. A lot of it gets out into the open lake. We know that mussel excretion, at 506 milligrams per square meter. 

This is the relative importance of phosphorous flowing from the river to the near shore region. And that importance changes as you move away from the river. When you're really close to the river mouth, obviously the river is an important source of phosphorous. As you move away from the river mouth, mussels start to become more dominant. So when you get 20-25 kilometers away, less than 10% of the phosphorous in that area would be coming from the river, and over 90% would be coming directly from mussel excretion. So a lot of the parts of the lake fit into this category. If you're not close to any major river, mussels are going to be the dominant source of phosphorous. Why is that? We're not sure, but there's a couple of possibilities. You see here in May and June of 1996-2001, we don't have data beyond that yet. 

But we had higher phosphorous concentrations in the spring of this area than we did previously. So we're getting a spring slug of phosphorous. If we look at river discharge, we're seeing the same thing. In May and June of this most recent era, there's more water from the phosphorous concentration. So we're getting this big slug of phosphorous coming into the lake during the spring, just due to weather conditions over the last few decades. What's another possible cause of increased input from rivers? It may be phosphorous in the soils. This is phosphorous content of soils through Wisconsin cropland. Just going up to '99. What you can see is that the steady increasing trend. 

This is higher than what most crops need. But because of fertilizer and the newer applications, our croplands are continuing to increase in phosphorous concentration. This is the soil storage change. What this is, is just the input minus the output. When this reaches zero, that means we've got a balance. But as of 1995, we were still putting more into the soils than we were taking out of them. Just to show you, I showed you earlier the phosphorous trend for the Milwaukee River. Here's the trend for the Manitowoc River. It came down until the mid-1970s. It hasn't done much since then. 

It's stayed pretty steady, averaging around .2 or .25, which is higher than the Milwaukee River. The Milwaukee River now, even with that increase, is more around .15. So fairly high concentrations of total phosphorous in the Manitowoc River. We've got particulate phosphorous and dissolved phosphorous entering our rivers. That dissolved phosphorous can be taken up directly by the Cladophora. The particulate phosphorous, they can't use, or if it's fed on by mussels, they're going to excrete some of that as dissolved phosphorous, which is available to the Cladophora. We also have what I'm calling the offshore loop. A lot of this phosphorous can just bypass the near shore zone and go right out into the open waters. This is dissolved phosphorous where it becomes taken up by plankton. Eventually that plankton may come back to the near shore, where it's fed on by mussels, and then made available to the Cladophora. 

And what we want to know is the relative importance of these two loops here. This is important to consider, because there's a huge mass of phosphorous in Lake Michigan. There's much more phosphorous in Lake Michigan than what enters the lake on annual basis from the rivers. So there's potentially a huge amount of phosphorous from here that could be promoting Cladophora growth, if it's being funneled in by feeding from mussels. And it's important to know the relative importance of these two loops, this offshore loop and this near shore loop, because if we reduce phosphorous inputs into Lake Michigan, if we were, by some magic, able to reduce phosphorous by 50% in all of the rivers entering the lake tomorrow, then if the near shore loop was dominant, this is what would happen to phosphorous concentrations in the near shore zone. Within a year, they would drop down and we would get that 50% that we would like to shoot for. It would happen very quickly. But if that phosphorous is flushing out into the open lake, and we've got a way for that phosphorous to be reduced in the open lake, we're going to have to wait a much longer time. Because, as I said, there's a huge pool of phosphorous in the open lake. It's going to take a long time for that respond to any decrease in phosphorous coming from the rivers. 

This is the time span we're looking at there. We're looking at a ten year time span to get lake concentrations down by 50%. That's based on the Lake Michigan program model that was produced back in the '90s. So to conclude then, the main points. The primary factor responsible for the recent increase in Cladophora, is the big water clarity. There is a contribution from increased phosphorous inputs, but the main factor is water clarity. A secondary factor is increased phosphorous concentrations. And mussels, appear to be the main source of phosphorous within the near shore area. We have this increase in water clarity. Like I said, there's nothing we can do about it. 

We've got this target level of seven micrograms per liter of total phosphorous in Lake Michigan. And yet we still have a Cladophora problem in the near shore waters. What I'm suggesting is that this change in water clarity is forcing us to reconsider this target level, because it's not working for the near shore waters. We may have to set a new target for the near shore waters, because those waters are more clear now. The greater light abundance has overbalanced our phosphorous management strategies. The Cladophora models suggest that at depths greater than seven meters, 50% phosphorous reduction would result in a significant decline of Cladophora abundance. At shallower depths, the response is less certain, because we're not sure yet how well the model works at shallower depths. Finally, reducing phosphorous concentrations in Lake Michigan is a long-term process, for two reasons. One is, as I just mentioned, the lake is this big giant. It's going to take a while to respond to anything we do in the watershed. 

The other reason, I showed you earlier, we've been increasing phosphorous concentrations in cropland soils. And that's this huge mass of phosphorous where, it's a legacy that we're going to be living with for a while. Even if we change our management practices right now, there's a lot of phosphorous in the soils that's going to keep coming into the rivers and lakes over decades and even centuries to come. And I'll finish with that. 
(applause)
 
- Interesting presentation. But one piece that seems to be missing from here is sewage. You never mention sewage. We all know about the sewage, particularly in Milwaukee and other major cities around the Great Lakes. 

They've been dumping billions of gallons in. And we all know it contains, it's very phosphorous laden. So why isn't that part of your study and part of the solution? And secondly, probably a minor part of it, those little white birds that fly over everywhere, those two-legged poop machines, better known as seagulls, are just out of control around the Great Lakes. And a lot of beaches have been closed because of that, and you haven't looked at that either. I suspect that's minor compared to the sewage, but those two things seem to be missing here. 
- Right. They're both certainly issues when we think about beach water quality, beach closings and so forth. They're very relevant issues. With regard to Cladophora and to phosphorous cycling in Lake Michigan, sewage may be an important local issue. 

But in the larger scheme, even not all of Lake Michigan, but just for example, the area I showed you from Fox Point to Wind Point. The sewage contribution to phosphorous flowing into that area is negligible compared to all the other phosphorous inputs. Even if we ignore the mussels, just the loading from the river, the majority of phosphorous is coming from the river, from surface run-off from the land. I intentionally don't emphasize sewage in here, because my concern is that I think a lot of the public has been misled over the last number of years, because the media has given a lot of attention to sewage overflows, and that's understandable, because there is a health threat associated with that. But that is not contributing to the Cladophora problem in Lake Michigan. You can go to Manitou Islands and Sleeping Bear Dunes National Park on the other side of the lake, which are ten miles offshore, and their Cladophora problem is as bad as many other parts of the lake on this side, and there's no sewage input there. It's in-lake processes that are causing the problem that we're seeing there. So I'm trying to correct the perception that a lot of the public have that sewage is contributing to the Cladophora problem, because it really isn't. The bird issue, again, is an obvious health issue. And it ties into the beach closing problem. 

But with regard to Cladophora, and with regard to phosphorous increase to the lake, it's really not an important problem. Cladophora does tie in there in that the bacteria can come from birds or other sources. They tend to persist longer in Cladophora, so it confounds the whole process of trying to define water quality, because we use those as the main indicator of water quality. And if you have this reservoir of bacteria in the Cladophora that's either in the water or sitting up on the beach, that confounds the process of monitoring bacteria in water, because they may be leaching out of this Cladophora over a longer period of time than if you had no Cladophora. 
- Are you getting less 
(inaudible)
 from the mussels, because the water is clearer, and there's less biomass available for the mussels to filter. 
- There will be a negative feedback there. Eventually, they may eat themselves out of house and home, so to speak. The measurements we have been making over the last two years, where essentially it looked like mussels have done everything they can in the near shore zone. 

They really have cleared up the water, they've reduced the amount of plankton there. So I think the measurements that we're making now are representative of the conditions you're describing, where they're doing as little as they can right now. We don't have historic measurements in Lake Michigan to say five or ten years ago, where the mussels excreted more phosphorous than they are today. But I don't think it will get any less than it is now, because they've kind of reached that climax stage of their impact on the near shore environment. 
- In this area, most of the phosphorous seems to be coming from the farmlands. And what would be, to get a 50% reduction, what exactly has to be done? 
- I'm probably not the best person to address that. Most of our work is focused on the lake itself, and what's going on in the lake, looking at phosphorous with an interest in the lake and the rivers. We haven't gone much upstream in the rivers to figure out where is this phosphorous coming into the rivers, what are the sources, which we need to do to really start targeting sources that we can manage. And I'm not an expert in that area. 

We do know that a lot of it does come from non-point agricultural run-off. Or we've done some work in the Milwaukee River that shows that urban sources are also significant. If you look at phosphorous concentrations as you go down the Milwaukee River, there's a significant increase when you get into the metropolitan Milwaukee area. So there are sources there as well, which again, we're guessing at now, but we're not definite on what they are. I would just say that we still need to be concerned about the Soil P content, which is increasing, still going up. We need to get that Soil P concentration down. And we obviously need to reduce run-off. I think there's a focused way to do this. And I know that folks at UW Madison are working on how we can highlight the hot spots for soil phosphorous run-off in agricultural land. Rather than applying a strategy to all agricultural land, try to identify the hot spots and focus your management on those hot spots to reduce erosion and run-off from those hot spots. 

- Is there a possibility, is there something that can take care of the mussels? 
- Some people have worked on that, with limited success so far, looking at pathogens that might work on them. There are chemical ways to control them, but in a lake as large as Lake Michigan, those are not options. To my knowledge, there's no promising pathogens right now that we would put into Lake Michigan to try to control mussels. I should mention, though, in regard to that, that mussel numbers fluctuate from year to year. They're still relatively new in Lake Michigan. We may see mussel numbers change over the next five to ten years. Gobies are becoming more established in Lake Michigan, and they feed on mussels. They may put a dent in the population. Other natural mechanisms may reduce their numbers, as well. 

We haven't monitored within the last couple of years, but based on our data, it looks like there are fewer mussels now than there were two or three years ago. We know there are hot spots along the lake shore, where Cladophora is a big problem. Bradford Beach is a problem. Despite the fact that Cladophora is growing all along the lake shore, and the reason for those hot spots, I believe, is because of near shore hydrodynamics, which force the Cladophora to accumulate in certain areas along the shore. There may be some management option there, but I think ultimately the management option is to reduce the amount of Cladophora that's growing in the lake. If I could just mention one more thing. This problem is also occurring in Lake Erie and Lake Ontario, even more so than it is here, to the point where people have to move out of their homes for part of the summer in New York on Lake Ontario, because the smell is so bad. The Corps of Engineers did a large study there in Monroe County to look at options to manage the Cladophora. And they were all engineering options, trying to remove it when it came up on the beach, trying to get it even before it came up on the beach by pumping it away. And in the end, none of them worked. 

(applause)