The state legislature in Minnesota is looking at a bill that would restrict phosphorus levels in automatic-dishwashing detergents. Supporters say it would reduce harmful algae blooms in lakes and streams. If the bill passes, it would be the first state to make such restrictions. The Great Lakes Radio Consortium’s Christina Shockley reports:
Transcript
The state legislature in Minnesota is looking at a bill that would restrict phosphorus levels in
automatic-dishwashing detergents. Supporters say it would reduce harmful algae blooms in lakes
and streams. If the bill passes, it would be the first state to make such restrictions. The Great
Lakes Radio Consortium’s Christina Shockley reports:
Phosphorus in detergents helps to clean dishes, but when the mineral ends up in lakes and
streams, it promotes algae blooms. Large algae blooms can kill fish and restrict sunlight to
bottom-rooting plants. In the 1970s, phosphorus was restricted in other types of detergents.
David Mulla is a professor in the soil, water, and climate department at the University of
Minnesota. He says that legislation did make a difference.
“We had a very large reduction in the amount of phosphorus that was being emitted to our waste
water treatment plants as a result.”
However, Mulla says dishwashing detergents are not one of the primary sources of phosphorus in
lakes and streams today. Detergent manufacturers say if they don’t use phosphorus, their
detergents might not meet some health standards. They also say a reduction won’t have any
environmental benefits. The bill is currently being discussed in the state legislature.
For the Great Lakes Radio Consortium, I’m Christina Shockley.
States have been removing old dams from rivers for safety and environmental reasons. But researchers say water managers should be sure to take a close look when considering dam removal as an option because, in some cases, it might be bad for the environment. The Great Lakes Radio Consortium’s Mark Brush has more:
Transcript
States have been removing old dams from rivers for safety and
environmental reasons. But researchers say water managers should be
sure to take a close look when considering dam removal as an option
because, in some cases, it might be bad for the environment. The Great
Lakes Radio Consortium’s Mark Brush has more:
This year, 45 dams are slated for removal across the country. Half of
those dams are in this region.
Emily Stanley is a river ecologist at the University of Wisconsin.
She’s been studying rivers after a dam has been removed and recently
published her findings in the journal “BioScience.” She
says in farm country, dams can help trap fertilizers that have been
over-applied on nearby fields.
“Small reservoirs can act like wetlands, and can be effective filters
for removing the nitrogen that has come in off of farm fields through
groundwater into the system, and can be actually some valuable points
of improving water quality.”
Stanley says, in many cases, sediments have been collecting behind the
dams for decades. When the dam is removed, the sediments are suddenly
released downstream and can lead to harmful algae blooms. In some
cases, the sediments can contain more dangerous substances, such heavy
metals and PCB’s. Stanley says communities should be sure to weigh the
environmental consequences before removing a dam.
For the Great Lakes Radio Consortium, I’m Mark Brush.
Zebra mussels have been colonizing North American lakes and rivers since 1991. Scientists have looked at many of the ways mussels affect those ecosystems. But a new study underway shows how those effects are moving up the food web…and are having two very different results. The Great Lakes Radio Consortium’s Mark Brodie reports:
Transcript
Zebra mussels have been colonizing North American lakes and rivers since 1991. Scientists have looked at many of the ways mussels affect those ecosystems. But a new study underway shows how those effects are moving up the food web…and are having two very different results. The Great Lakes Radio Consortium’s Mark Brodie reports:
Between 50 and 5-hundred billion zebra mussels now live in New York’s Hudson River. That’s a lot of hungry mouths to feed on the river’s zooplankton and phytoplankton. The problem is the mussels are not the only ones that like to dine on the microscopic plants and animals. A new report suggests the mussels are stealing food from some of the river’s fish.
That’s forcing those fish to look elsewhere for their meals. Sandra Nierzwicki-Bauer is the director of the Darrin Freshwater Institute, and a biology professor at Rensselaer Polytechnic Institute in Troy, New York. She says the zebra mussels can dramatically alter an ecosystem.
“They’re very rapid filter feeders, and as such, they’re able to remove tremendous amounts of phytoplankton, algae, bacteria in the water column. As such, the phytoplankton serves as food sources for other organisms so you really are impacting the entire food web.”
Nierzwicki-Bauer says those impacts go all the way up to fish. David Strayer is a freshwater ecologist at the Institute of Ecosystem Studies, and a lead author of the report on the Hudson River. He says his team studied fish populations in the Hudson both before and since zebra mussels colonized there.
“In open water fish species, we saw a decline in abundance, we saw declines in growth rates, and we saw that the populations of those fish tended to shift downriver compared to the period before the zebra mussel invasion.”
That means some of the most common and popular fish in the Hudson are no longer where they used to be…among them American shad, herring, and white perch. That’s because the zebra mussels are eating those fish’s food…forcing the fish to go elsewhere.
But Strayer says while some fish have had to move away from the mussels…some species have welcomed their new neighbors.
“In the same period of time, we saw populations of fish that live in the weed beds…we saw those populations increase, we saw growth rates of those fish increase, and we saw the populations of those weed bed fish shift upriver into the area where the zebra mussels lived.”
These forage fish have more to eat because the plants at the river’s bottom are growing more. That’s because the zebra mussels clear up the water, which allows more sunlight to reach the plants. Strayer says the zebra mussels have changed almost everything about the Hudson’s ecology.
But he says some of those changes have been difficult to predict, and the changes may not apply to all bodies of water where the mussels have colonized. This is one of the first studies using long term data that looks at the zebra mussels’ affect on fish populations…but there is some evidence that other bodies of water are dealing with similar situations. There have been reports that zebra mussels may be affecting smelt and chub in Lake Michigan…these smaller fish are food for larger species, such as trout and salmon. But while the results are comparable, David Strayer says the changes in the Hudson River are more pronounced than changes elsewhere.
“This isn’t because we have more zebra mussels in the Hudson than in the other places, but it’s because there are differences in the structure of the ecosystem between the Hudson River and the Great Lakes and other places that have been invaded. So, you have to be a little cautious extrapolating from one body of water to the next.”
That sentiment is shared by Andy Kahnly. He’s a fishery scientist with the Hudson River fishery unit of the New York State Department of Environmental Conservation. He also worked on the new study. Kahnly warns for now, the results only apply to young fish…and not adults. That’s because fish can live up to 30 years, and the data don’t go that far back.
“Quite often, changes in early lifestages will take some time to translate into changes in fish populations and then to changes in fish communities. So it takes a lot of data, a lot of years of data to see a change.”
Kahnly says that means anglers in the Hudson might begin to notice some changes over the next few years… and he says the study did find a dramatic decrease in many of the species that people catch.
“If these changes in production of young persist into the future, then definitely there will be a decrease in the abundance of the adults which people are fishing for.”
But that depends on what you’re fishing for. The Institute of Ecosystem Studies’ David Strayer says your perspective might change depending on that you’re trying to catch.
“If you’re concerned about shad populations, if you’re a shad fisherman, then you might be concerned with the zebra mussel invasion and think it’s a bad thing. If you like the weed beds, if you’re a duck hunter or a large mouth bass fisherman this might be regarded as a positive thing.”
Strayer says the study shows zebra mussels are capable of having a tremendous impact on an ecosystem. He says it also shows the importance of being careful to prevent the introduction of invasive species…like zebra mussels…into an ecosystem.
For the Great Lakes Radio Consortium, I’m Mark Brodie.
Across the country, forests, streams and coastlines are getting extra doses of nutrients containing the element nitrogen. Researchers say the long-term impact of these unwanted compounds on the environment could be serious. The Great Lakes Radio Consortium’s Daniel Grossman reports on some efforts to reduce nitrogen pollution:
Transcript
Across the country, forests, streams and coastlines are getting extra doses of nutrients
containing the element nitrogen. Researchers say the long-term impact of these unwanted compounds on the environment could be serious. The Great Lakes Radio Consortium’s Daniel Grossman reports on some efforts to reduce nitrogen pollution:
A thunderstorm soaks the land and lights the sky. The electric jolts of the lightning change nitrogen in the air into compounds needed for plants to grow. Lightning, as well as microbes in the soil, converts annually nearly 100 million tons of atmospheric nitrogen into plant nutrients. Humans make the same compounds in factories and call them fertilizer, a mainstay of agriculture. Between these synthetic chemicals and a smaller quantity of related compounds produced when fossil fuels are burned, humans produce more nitrogen-rich nutrients than nature makes on the seven continents. University of Minnesota ecologist David Tilman says such extra nutrients are a concern.
“Right now half or more of the nitrogen we put on a farm field just washes through the soil and down into the groundwater into lakes, rivers, streams and into the ocean.”
This wasted nitrogen often travels great distances causing widespread damage. Tilman says on land, the nutrients cause exotic weeds to outgrow native plants. In the ocean, the nutrients cripple critical habitats. The ecologist says nitrogen pollution must be cut. One place to start is on the farm.
“We have to find some way to grow crops where the crops take up much more of the nutrients that we apply.”
(Sound of walking through grass. Quiet bird calls in background.)
Near Chesapeake Bay, farmer and agricultural scientist Russ Brinsfield walks across a patch of tall dry grass.
We’re on the edge of a field, about a sixty-acre field of corn, on the beautiful Eastern Shore of Maryland.
This field is a research plot at the Maryland Center for Agro-Ecology. Here Brinsfield is studying agriculture’s environmental impact. Chesapeake Bay’s waters have high concentrations of farmer’s nutrients, causing blooms of the toxic algae Pfiesteria. The pollution has also caused declines in sea grass beds. Brinsfield says solutions to the problem fall into two categories.
“The first series of practices are those practices that we’ve been able to demonstrate that by a farmer implementing them he can reduce his inputs without affecting his outputs… that at the end of the year have added profit to his bottom line.”
For instance, testing the soil’s nitrogen level before fertilizing. And splitting fertilizer applications into two doses rather than one so that nutrients are added only when plants need them. Such simple measures are good for environment and the bottom line. Brinsfield says in the last 10 years most farmers on the Eastern Shore of Maryland have cut fertilizer use this way. Then there’s the other category of improvements.
“We’re going to have to do some things-ask some farmers to do some things-that may cost them more to do than what they are going to get in return from that investment.”
For example, in the winter, many fields here are fallow and bare. That means top soil erodes when it rains, taking with it residual fertilizer. It wasn’t always this way.
“I can remember my dad saying to me, ‘every field has to be green going into the winter, Son.’ So all of our fields were planted with rye or wheat or barley. It served two purposes. First, the animals grazed it. And second, it held the soil intact.”
And intact soil retains its fertilizer. Such winter cover crops also prevent fertilizer loss by storing nutrients in plant leaves and stalks. This used to be dairy country and cover crops grazed by cows made economic sense. Now farmers mostly grow grains. Planting a cover crop could cut nitrogen flow from farms by 40 percent but it costs farmers about $20/acre and provides no economic benefit to them. Brinsfield says farmers need an incentive.
“For the most part, farmers are willing to participate and to do those things that need to be done, as long as they can still squeak out a living.”
To help them squeak out a living, the state pays some farmers to sow cover crops. The state also pays them to plant buffers of grass and trees that suck up nutrients before they leave the farm. Today farms in six states that are part of the Chesapeake’s huge watershed contribute about 54 million pounds of nitrogen to the bay. The goal is to cut this figure approximately in half by two thousand and ten. Robert Howarth, a marine biologist and expert on nitrogen pollution at Cornell University, says though ambitious, this target can be achieved.
“I think most of the problems from nitrogen pollution have relatively straightforward technical fixes. So the real trick is to get the political will to institute these.”
Howarth says much of the nitrogen problem could be eliminated with a blend of government subsidies and regulations. But more will be needed as well… solutions of a more personal nature.
(sound of Redbones Barbeque)
There’s a pungent, smoky aroma in the air at Redbones Barbeque in Somerville, Massachusetts. The crowded bistro serves up a variety of ribs, chicken, sausage and other meats, dripping with savory sauces. University of Minnesota ecologist David Tilman says when someone eats a meal they are responsible for the little share of fertilizer a farmer somewhere had to apply to grow a crop. If the meal is from farm-raised animals, like the heaping plates of meat served here, the amount of fertilizer is much greater than if it’s from plants.
“It takes from three to ten kilograms of grain to produce a single kilogram of meat.”
Tilman says if Americans ate less meat, they could dramatically reduce fertilizer usage. However, per capita consumption is rising. Meat consumption is on the rise globally as well. David Tilman would like that to change. He says if current trends continue, human production of nitrogen nutrients will grow to triple or quadruple what nature makes on all Earth’s lands. Professor Tilman says that in many places the impact on the environment would be catastrophic.
For the Great Lakes Radio Consortium, this is Daniel Grossman.
The Great Lakes suffer from all kinds of pollution, but among the most dangerous pollutants from industrial waste are mercury, cadmium, and zinc. Researchers at Ohio State University are perfecting a way to clean up those heavy metals…. using algae. The Great Lakes Radio Consortium’s Bill Cohen explains:
Transcript
The Great Lakes suffer from all kinds of pollution, but among the most dangerous pollutants from industrial waste are mercury, cadmium, and zinc. Researchers at Ohio State University are perfecting a way to clean up those heavy metals – using algae. The Great Lakes Radio Consortium’s Bill Cohen explains:
Picture using algae as a sponge. The one-cell
plants attach themselves to the polluting metals…you pull them out of the
water…squeeze out the metals in an acid solution….and re-use the algae
sponge 30 times. Researcher Richard Sayre has genetically altered the
algae to sop up more pollution than ever:
“We’ve improved their ability to sequester and bind these heavy metals by a factor of five.”
Sayre stresses – the algae itself won’t be put
into the lakes free-floating …and it won’t even be living.
“The metal-binding capacity is about three times greater when they’re dead than when they’re alive.”
The next step for Sayre…convincing a few cities to let him put this algae into pollution control equipment so he can prove to them it’s a cheap and effective way to stop industrial waste before it gets into waterways.
For the Great Lakes Radio Consortium, I’m Bill Cohen.
Researchers are developing models to try to
determine what the effects of global warming will be on the
Great Lakes region. Photo by Jerry Bielicki.
Some scientists in the Great Lakes basin are looking at how global warming might be affecting the region, both today and long into the future. The Great Lakes Radio Consortium’s Lester Graham has the story:
Transcript
Some scientists in the great lakes basin are looking at how global warming
Might be affecting the region, both today and long into the future. The
Great lakes radio consortium’s Lester graham reports.
Many researchers in a number of different fields are coming to the same basic conclusion: the earth is warming and it’s affecting the Great Lakes. So far, the effects have been difficult to track, unlike watching the day-to-day changes in the weather. Measuring climate change requires measurements over many decades, or better yet over centuries. There are only a few places where weather measurements have been taken over that long of a period. But, where they have, researchers are finding weather is becoming more chaotic and indications are that the long-term climate is warming.
Many climatologists believe that warming is due at least in part to greenhouse gases, that is, pollution in the upper atmosphere trapping more of the sun’s heat, much in the same way a greenhouse works.
Taylor Jarnigan is a research ecologist with the U-S Environmental Protection agency who’s been looking at one aspect of climate change. He’s been studying whether increasing amounts of lake effect snow from Lake Superior over the past century, especially the past 50 years, is evidence of a change in the temperature of the lake. Preliminary study suggests that the lake’s surface temperature is warming, and that causes more snow when cold air passes over it. But he says the amount of snow has varied widely from year to year.
“Some of this variability is certainly due –in my opinion– to an increasing volatile climate system itself. El niño and la niña are becoming more intense, so you have an increasing oscillation between, say, an usually warm summer followed by an unusually cold winter which tends to produce an unusually large amount of snow.”
The surface temperature of the lake has only been monitored for a few decades, while snowfall depths have been recorded for much longer. Jarnigan says, since there seems to be a direct correlation between the surface temperature of the lake and snowfall, he can calculate the temperature of the lake going back more than a century, and finds that Lake Superior is getting warmer.
When researchers find direct measurements that have been taken for more than a century, they feel fortunate. For example, John Magnuson with the University of Wisconsin has been reviewing the conclusions from the Intergovernmental Panel on Climate Change. That’s the international organization established by the United Nations to study global warming. As a part of that review, Magnuson has been looking over shipping and harbor records that date back 150 years or more to see if there’s evidence of global warming. One thing he’s learned is that lakes and streams aren’t iced over for as long as they once were.
“And in the last hundred-and-fifty years we’ve seen significant changes in lakes around the entire– lakes and streams around the entire northern hemisphere. The date of freezing on the average and the date of break up is changing by about six days per century.”
And Magnuson says that six day change on both ends of the freeze-thaw cycle mean that there’s nearly two weeks less ice coverage than a century ago.
That seems to bolster research at the National Oceanic and Atmospheric Administration’s Great Lakes Ecological Research Laboratory. Studies there indicate that over the last several years Great Lakes ice coverage on average is not as far ranging and doesn’t last as long as it did historically.
There’s no certain way to tell what might happen to the Great Lakes if the apparent warming trend continues.
But there are some ways to speculate. There are at least two computer models that try to estimate how much warmer the climate in the Great Lakes region might become by the year 2090. Based on those models, researchers have tried to figure out what that might mean for the area. Peter Sousounis was working at the University of Michigan at the time of that research. He says using either computer model it looks as though crops would produce more. Soybean yields could double. But other predictions are not as beneficial. It looks as though Great Lakes water levels would drop, probably about three feet more than they’ve already dropped, causing some problems for shipping. The study also found algae production would decrease by 10 to 20 percent. That’s important because algae provide the base for the Great Lakes’ food chain. Pine trees might also be all but eliminated from the region, and Sousounis says dangerously high ozone days might occur twice as often.
“Our findings indicate there are some potentially serious consequences in terms of reduced lake levels impacting shipping across the region, some serious economic impacts that if we don’t learn how to deal with these, there are going to be some serious changes in our lifestyles.”
Critics say the models can’t represent all of the variability in nature, so it’s difficult to be sure about any of the predictions. An adjustment here or there can lead to all kinds of alternative scenarios. Sousounis concedes more work needs to be done and more variables plugged into the models, but he’s convinced change will come; the degree of change is the only question.
These days, very few scientists argue against the studies that suggest the earth is warming. John Magnuson with the University of Wisconsin says a few DO argue that the change might merely be natural climate variability – that is, Mother Nature taking an interesting twist– and not necessarily a warm-up caused by manmade greenhouse gases.
“The skeptics, or the more cautious people, what they do when they look at that range of variation over the last thousand years, what they see is there is a signal in the warming that’s coming above the historic variation of climate. And, the climatologists of the world collectively feel there’s very strong evidence that warming is occurring, that greenhouse gases are a very significant part of that warming.”
Magnuson says most mainstream scientists agree climate change is happening, and even dramatic reductions in greenhouse gases won’t prevent some continued global warming over this century. But most say reducing pollution would slow the rise in temperatures and curtail the warming sooner. Only time will tell how that warming will change the Great Lakes region, and all of the researchers we talked to say in the meantime we’ll likely see more chaotic roller coaster type weather patterns as never before in recorded history.
For the Great Lakes Radio Consortium, this is Lester Graham.
Researchers are developing models to try to
determine what the effects of global warming will be on the
Great Lakes region. Photo by Jerry Bielicki.
Researchers are trying to determine how global warming might affect this region. The Great Lakes Radio Consortium’s Lester Graham reports:
Transcript
Researchers are trying to determine how global warming might affect this region. The Great Lakes Radio Consortium’s Lester Graham reports.
Using two different sophisticated computer climate models, researchers are asking questions such as what happens to the water levels in the Great Lakes. Both models predict they drop even farther, causing shipping problems. They predict crops will produce more, and they predict some trees will die off. Peter Sousounis is one of the researchers studying the models. He says the region needs to consider what appears to be happening.
“I’m concerned that we won’t be prepared, we will not have done our homework. I think as a society we can certainly adapt, if we are given enough time. And if we don’t adapt, life might adjust to a new mean state all around.”
While nearly all climatologists believe the earth is warming, not everyone agrees whether the changes will be harmful. Sousounis agrees more research needs to be done to try to determine what the effects might be. For the Great Lakes Radio Consortium, this is Lester Graham.
Summers in the Midwest mean corn, county fairs and lots of heat and humidity, but while some seasonal traditions remain intact, Great Lakes Radio Consortium commentator Julia King recently discovered that at least one significant summer custom is slipping away:
Fertilizer used in the Great Lakes states and the Midwest might be causing a wider dead zone in the Gulf of Mexico than ever before. The Great Lakes Radio Consortium’s Lester Graham has the story:
A Sea Grant researcher in Ohio has genetically engineered a
single-celled algae to work as a pollution solution. The algae binds
with heavy metals in lakes and then is harvested. The metals are removed
with the algae. The Great Lakes Radio Consortium’s Aileen LeBlanc has
the story:
