The Invasion of the Quaggas

  • A close-up of the quagga mussel. Quaggas have spread in all of the Great Lakes except Lake Superior. (Photo courtesy of the Michigan Sea Grant Archives)

Whitefish is a main dish for everything from fish boils to fancy dinners all around the Great Lakes region. But in some areas of the Great Lakes, whitefish aren’t doing so well. Rebecca Williams reports on what’s happening to the fish many people love to eat:

Transcript

Whitefish is a main dish for everything from fish boils to fancy dinners all around the Great Lakes region. But in some areas of the Great Lakes, whitefish aren’t doing so well. Rebecca Williams reports on what’s happening to the fish many people love to eat:

(sound of knives getting sharpened and fish being filleted)

Mike Monahan sells fish from all over the world at his seafood market. But he says whitefish is a very popular seller.


“It’s been there forever, and everybody just expects it to be there, and it’s inexpensive. But really it’s a great fish, as far as a nice light delicate fish, I’d put it up against the soles and flounders.”


Monahan says he’s still getting good supplies of whitefish. So, for now, he’s happy.


But some of the people who catch whitefish are worried. Commercial fishers have been hauling in skinnier whitefish in some parts of the lakes. It’s taking whitefish longer to grow to a size worth selling. And in some cases, the fish aren’t fat enough to make a good fillet.


(sound of shorebirds)


Paul Jensen fishes for whitefish in Lake Michigan. He says lately, he’s had to move his boat to deeper waters. That’s because whitefish are hungry and they’re swimming out deeper. They aren’t finding their favorite food. It’s a little shrimp-like creature called Diporeia.


“Diporeia are probably like a Snickers bar to whitefish; they were high in fats, high in lipids and it was their main food – it was very nutritious for them and it affected their growth rate. Eating Diporeia a fish could reach maturity maybe in 18 months or 2 years. Now we’re looking at fish that may take 5 years to get there.”


Whitefish are not eating Diporeia because it’s vanishing. In some places, researchers used to find 10-thousand of the little critters in a square meter of sediment. Now there are very few, or none at all.


Tom Nalepa has been trying to figure out why. Nalepa is a biologist with the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Lab.


“It’s a real scientific puzzle as to why Diporeia is declining. It’s definitely related to the spread of quagga mussels and zebra mussels but that exact negative relationship is kind of elusive at this point in time.”


But Nalepa says he’s sure the invasive mussels are to blame. The mussels got into the Lakes in the ballast tanks of foreign ships. And they’ve spread in all the lakes except Superior.


Tom Nalepa says he’s seen populations of Diporeia crash right around the time the mussels were booming. Nalepa says now, Diporeia’s gone from large areas in most of the Lakes.


That’s bad because Diporeia is an important food source for most of the fish in the Great Lakes.


But for whitefish it’s really crucial. Back in the good old days, Diporeia made up about 80% of their diet.


Tom Nalepa says whitefish are trying to find something else to eat. He’s seeing them switch to a snack food that could make them even skinnier.


They’re starting to eat quagga mussels.


“When whitefish feed on quagga mussels they have to deal with the shell which has no energy content at all and it has to pass the shells through its digestive system so basically the fish feels full when it’s not getting any energy source.”


Nalepa says to the fish, quagga mussels must seem like good food, because there are lots of them.


He says quagga mussels are booming, because they can live in harsher conditions than zebra mussels can. So biologists are predicting quaggas will be even worse for the lakes than zebra mussels.


“Where are things ultimately going to end up? People may just have to get used to fewer fish. Because basically now we’re trading the fish community for the mussel community. The lakes are loaded with mussels instead of fish now. It may be just the way it’s gonna be.”


Some fishermen are already seeing things change. One day last season, Paul Jensen pulled in some of his nets. He was expecting fish.


“It was kind of startling because the amount of quagga mussels that came up with those nets far exceeded the catch of fish. And we hadn’t really equipped the boat with a snow shovel to shovel quagga mussels out of the boat. The impacts are startling because you begin to wonder, if our little net caught these, how many are there and what are the impacts going to be down the road?”


Jensen says he wishes the invaders had never gotten into the lakes in the first place, because there’s no way to predict what effect they’ll have next.


But some scientists worry these changes at the bottom of the food chain will lead to a major collapse of the fish stocks that many people depend on.


For the Environment Report, I’m Rebecca Williams.

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Invasives Destroying Great Lakes Food Chain

  • Biologists sorting fish. The populations of smaller fish that game fish eat have collapsed in Lake Huron. (Photo courtesy of MI DNR)

Although zebra mussels have been affecting the ecology of the Great Lakes since they were first found in 1988, researchers are continuously surprised at how much damage they’ve caused. Now, biologists are wondering if zebra mussels and the more recently arrived quagga mussels are to blame for a collapse of the fishery in one of North America’s largest lakes. Lester Graham reports the researchers are also wondering if this collapse is a preview of what will happen to all of the Great Lakes:

Transcript

Although zebra mussels have been affecting the ecology of the Great Lakes since they were first found in 1988, researchers are continuously surprised at how much damage they’ve caused. Now, biologists are wondering if zebra mussels and the more recently arrived quagga mussels are to blame for a collapse of the fishery in one of North America’s largest lakes. Lester Graham reports the researchers are also wondering if this collapse is a preview of what will happen to all of the Great Lakes:


It’s off-season for charter boat fishing and Captain Wayne Banicky asked if we could meet at a local watering hole called the Boat Bar. Captain Banicky takes people out fishing on Lake Huron. Well, he used to. The past few years he’s been charter boat fishing in Lake Michigan. He says fish started to become more scarce on Lake Huron, and he was forced to make the move.


“Economics, pure and simple. Dollars and cents. Once you start seeing a decline and being on the water every day and you see those declines in your numbers, it’s just a matter of time before financially you can’t afford to stay there. Those dock fees aren’t given up free. That’s an expensive tab to pay every year.”


Fishing for most species in Lake Huron is not good. But the story is not just a matter of not stocking enough fish or just a bad year, it’s a matter of a collapse of the bottom of the food chain. It’s not just the fish sport fishers like to catch that are down, it’s their prey: the smaller fish those big game fish eat. Prey fish stocks have collapsed, and supplies of the food those small prey fish eat, the plankton, have also collapsed.


Jim Johnson is with the Michigan Department of Natural Resources Alpena Fisheries Research Station.


“There was a huge decline in the amount of nutrients available to zooplankton and phytoplankton in the middle of Lake Huron. These are the basic nutrient bits that fish eat. And it appears now to most of us in the scientific community that a large portion of the nutrients that used enter Lake Huron are now being trapped by zebra and quagga mussels and not finding their way to alewives and other prey fish.”


Scientists from different government agencies and universities in the U.S. and Canada had been noticing changes, but things have gone seriously wrong very quickly in Lake Huron, and it might go wrong other places.


Tom Nalepa is with the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Lab. He says tiny aquatic food sources for fish, such as a shrimp-like organism called diporeia, are declining dramatically in other Great Lakes.


“All the players are in place for it to happen in these other lakes too, you know, the loss of diporeia, the expansion of quagga mussels. And maybe Lake Huron is the first to show a collapse in the prey fish. What does it mean? Well basically, you know, there’s not going to be many fish out there for the sport fisherman to catch anymore.”


And sport fishing is multi-billion dollar industry in the Great Lakes. Back at the Boat Bar, charter fishing boat captain Wayne Banicky says fishing is still good in Lake Michigan, but he worries when he thinks about what happened in Lake Huron.


“I think that the fishery as a whole in the Great Lakes is in serious jeopardy right now. Something’s got to be done.”


But the question is what? What can be done when invasive species are changing an entire ecosystem to the point the fishery collapses?


“I don’t know to be honest with you. I don’t think any one of us knows. It’s scary, that much I will admit to you. It is scary right now.”


And guys like Captain Banicky aren’t the only ones worried.


Jim Johnson at Alpena Fisheries Research Station says you can’t undo the damage that’s already done. It’s just a matter of waiting to see how nature responds to the invasive zebra and quagga mussels and other invaders. Johnson says the key is to prevent more invasive species from being introduced to the lakes.


“The best we can do right now, I think the single most effective thing we as managers can do, is to make it understood by the decision makers just how disruptive the invasive species are and try to put a stop to those.”


The source of many of these invasive species is the ballast tanks of foreign ships entering the Great Lakes. Some regulations have reduced the chance that more invasive species will hitchhike to the Great Lakes, but more are still getting in. In the meantime, agencies such as the US Environmental Protection Agency and the US Coast Guard say Congress hasn’t given them the authority to regulate foreign ships strictly enough to stop new invasive species from entering.


So, fishery managers can only watch the other Great Lakes for more signs of a collapse of the fisheries as they’ve only been able to stand by and watch happen in Lake Huron.


For the Environment Report, this is Lester Graham.

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Mild Winter Thanks to El Nino?

The northern part of the U.S. might be in for a mild winter.
That’s if predictions by government climatologists turn out to be true.
Mark Brush explains:

Transcript

The northern part of the U.S. might be in for a mild winter. That’s if predictions by
government climatologists turn out to be true. Mark Brush explains:


Warmer ocean temperatures in the Pacific are expected to drive changes in wind and
weather patterns over North America this winter. This climate event is commonly known as El
Niño. It means milder temperatures for the northern part of the country, and for the
southern part it means wetter than average conditions.


Mike Halpert is the head of forecast operations at the Climate Prediction Center for the
National Oceanic and Atmospheric Administration. He says NOAA scientists were not
expecting El Niño effects this year, but recent warming trends in the Pacific Ocean
forced them to change their predictions:


“Right now it’s kind of hard to say how strong this event’s going to become. If the event
strengthens, as we anticipate it will, then I imagine the forecasts that we currently have,
which again favors warmth through much of the northern part of the country, will
remain.”


Halpert says the effects of El Niño will mostly be felt this winter and should subside by
next spring.


For the Environment Report, I’m Mark Brush.

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Ten Threats: Dead Zones in the Lakes

  • These fishermen at Port Clinton, Ohio, are a few miles away from the dead zone that develops in Lake Erie every summer... so far, most fish can swim away from the dead zone. But the dead zone is affecting the things that live at the bottom of the lake. (Photo by Lester Graham)

One of the Ten Threats to the Great Lakes is nonpoint source pollution. That’s pollution that
doesn’t come from the end of a pipe. It’s oil washed off parking lots by storms, or pesticides and
fertilizers washed from farm fields. Nonpoint source pollution might be part of the reason why
some shallow areas in the Great Lakes are afflicted by so-called dead zones every summer.

Transcript

In another report on the Ten Threats to the Great Lakes series, reporter Lester Graham looks at a
growing problem that has scientists baffled:


One of the Ten Threats to the Great Lakes is nonpoint source pollution. That’s pollution that
doesn’t come from the end of a pipe. It’s oil washed off parking lots by storms, or pesticides and
fertilizers washed from farm fields. Nonpoint source pollution might be part of the reason why
some shallow areas in the Great Lakes are afflicted by so-called dead zones every summer.


Dead zones are places where there’s little or no oxygen. A dead zone develops in Lake Erie
almost every summer. It was once thought that the problem was mostly solved. But, it’s become
worse in recent years.


(sound of moorings creaking)


The Environmental Protection Agency’s research ship, the Lake Guardian, is tied up at a dock at
the Port of Cleveland. Nathan Hawley and his crew are loading gear, getting ready for a five day
cruise to check some equipment that measures a dead zone along the central basin of Lake Erie.


“What I have out here is a series of bottom-resting moorings that are collecting time series data of
currents and water temperature and periodically we have to come out here and clean them off and
we take that opportunity to dump the data as well.”


Hawley is gathering the data for scientists at several universities and the National Oceanic and
Atmospheric Administration’s Great Lakes Environmental Research Lab. The information helps
them measure the behavior of the dead zone that occurs nearly every year in Lake Erie…


“What we’re trying to do this year is get a more comprehensive picture of how big this low-oxygen zone is and how it changes with time over the year.”


One of the scientists who’ll be pouring over the data is Brian Eadie. He’s a senior scientist with
NOAA’s Great Lakes Environmental Research Lab. He says Lake Erie’s dead zone is a place
where most life can’t survive…


“We’re talking about near the bottom where all or most of the oxygen has been consumed so
there’s nothing for animals to breathe down there, fish or smaller animals.”


Lester Graham: “So, those things that can swim out of the way, do and those that can’t…”


Brian Eadie: “Die.”


The dead zone has been around since at least the 1930’s. It got really bad when there was a huge
increase in the amount of nutrients entering the lake. Some of the nutrients came from sewage,
some from farm fertilizers and some from detergents. The nutrients, chiefly phosphorous, fed an
explosion in algae growth. The algae died, dropped to the bottom of the lake and rotted. That
process robbed the bottom of oxygen. Meanwhile, as spring and summer warmed the surface of
Lake Erie, a thermal barrier was created that trapped the oxygen-depleted water on the bottom.


After clean water laws were passed, sewage treatment plants were built, phosphorous was banned
from most detergents, and better methods to remove phosphorous from industrial applications
were put in place.


Phosphorous was reduced to a third of what it had been. But Brian Eadie says since then
something has changed.


“The concentration of nutrients in the central basin the last few years has actually been going up.
We don’t understand why that’s happening.”


Eadie says there are some theories. Wastewater from sewage plants might be meeting pollution
restrictions, but as cities and suburbs grow, there’s just a lot more of it getting discharged. More
volume means more phosphorous.


It could be that tributaries that are watersheds for farmland are seeing increased phosphorous. Or
it could be that the invasive species, zebra mussel, has dramatically altered the ecology of the
lakes. More nutrients might be getting trapped at the bottom, feeding bacteria that use up oxygen
instead of the nutrients getting taken up into the food chain.


Whatever is happening, environmentalists are hopeful that the scientists figure it out soon.


Andy Buchsbaum heads up the Great Lakes office of the National Wildlife Federation. He says
the dead zone in the bottom of the lake affects the entire lake’s productivity.


“If you’re removing the oxygen there, for whatever reason, for any period of time, you’ve
completely thrown that whole system out of balance. It’s all out of whack. It could mean
irreversible and devastating change to the entire ecosystem.”


And Buchsbaum says the central basin of Lake Erie is not the only place where we’re seeing this
low-oxygen problem…


“What makes the dead zone in Lake Erie even more alarming is that we’re seeing similar dead
zones appearing in Saginaw Bay which is on Lake Huron and Green Bay in Lake Michigan.
There, too, scientists don’t know what’s causing the problem. But, they’re already seeing
potentially catastrophic effects on aquatic life there.”


State and federal agencies and several universities are looking at the Lake Erie dead zone to try to
figure out what’s going on there. Once they do… then the battle likely will be getting
government to do what’s necessary to fix the problem.


For the GLRC, this is Lester Graham.

Related Links

Mercury Report to Undercut Epa Trading Program?

Earlier this year, the Environmental Protection Agency issued rules to cut mercury emissions from coal-fired power plants. Critics called the rules weak. Now, a different federal agency may have data supporting their claims. The Great Lakes Radio Consortium’s Shawn Allee reports:

Transcript

Earlier this year, the Environmental Protection Agency issued rules to cut mercury emissions from coal-fired power plants. Critics called the rules weak. Now, a different federal agency may have data supporting their claims. The Great Lakes Radio Consortium’s Shawn Allee reports:


The National Oceanic and Atmospheric Administration examined where mercury pollution in Lake Michigan is coming from. The data haven’t been publicly released yet, but sources say Midwestern power plants are the biggest culprits.


If true, that could undercut the EPA’s new mercury trading program. That lets dirty power plants buy the right to pollute from cleaner ones. Howard Learner’s with the Environmental Law and Policy Center. He says the program’s wrong because it treats all mercury pollution equally.


“When it comes to mercury pollution, a trading regime essentially doesn’t work very well, because you have concentrated localized hot spots in which the pollution is highly toxic to the people who live in those communities.”


Several state governments are fighting the EPA’s trading program in federal court. They’d like NOAA’s data, but the states and public will have to wait until the EPA reviews it.


For the GLRC, I’m Shawn Allee.

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Study: Ozone Layer Decline Leveling Off

  • The ozone layer helps to protect Earth from UV radiation. (Photo courtesy of NASA)

A new study shows the ozone layer decline is leveling off. Ozone 10 to 20 miles above the Earth protects the planet from the harmful effects of UV radiation. The Great Lakes Radio Consortium’s Erin Toner reports:

Transcript

A new study shows the ozone layer decline is leveling off. Ozone 10 to 20 miles above the Earth protects the planet from the harmful effects of UV radiation. The Great Lakes Radio Consortium’s Erin Toner reports:


The study says a leveling off in the ozone layer decline follows a 1987 international agreement. It established controls for chlorofluorocarbons, or CFCs. The chemicals were used in air conditioning, refrigeration, and industrial cleaning.


Scientists say CFCs are the primary source of ozone destruction. Betsy Weatherhead is with the National Oceanic and Atmospheric Administration. She says despite the encouraging news, the ozone layer is still depleted.


“That means high UV radiation, which means that we still have to be vigilant about protecting our skin, protecting our eyes, and taking special care with our children.”


The study observed small increases in the ozone layer in some regions, but researchers say because CFCs stay in the atmosphere for decades, it may be forty years before the ozone layer is significantly repaired.


For the GLRC, I’m Erin Toner.

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Empty Ballast Tanks Still Carrying Critters

  • A scientist collects samples of ballast sediment. (Photo courtesy of NOAA)

A new study finds that ocean-going ships that enter the Great Lakes often carry biological pollution in their ballasts, even when they declare their ballasts are empty. The Great Lakes Radio Consortium’s Lester Graham reports:

Transcript

A new study finds that ocean-going ships that enter the Great Lakes often carry biological pollution in their ballasts, even when they declare their ballasts are empty. The Great Lakes Radio Consortium’s Lester Graham reports:


The study by the University of Michigan and the National Oceanic and Atmospheric Administration looked at ships coming into the Great Lakes from the ocean. Nearly 80-percent of them declared “no ballast on board” and avoided inspections by the Coast Guard.


But several of those ships were tested by the researchers. They found that although the ballast water was pumped out, there were thousands of organisms left behind in the sediment in the bottom of the ships’ ballast. Then, when the ships unloaded at their first stop, they took on Great Lakes ballast water which stirred up the sediment.


And that made it possible for the biological contaminants to be pumped out at the next Great Lakes port.


The authors of the study warn that more restrictions must be placed on how the ships handle ballast water, or the Great Lakes will continue to be invaded by more invasive species such as the zebra mussel, round goby, and 180 other foreign aquatic species that have harmed the Lakes’ ecosystems.


For the GLRC, this is Lester Graham.

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Action Plan Not Enough to Shrink Gulf ‘Dead Zone’

  • Small shrimp fishers are concerned about the Gulf of Mexico 'dead zone' because shrimp can't survive in the oxygen depleted water. (Photo by Lester Graham)

The government has been working with agriculture, environmentalists and scientists to come up with a way to reduce the size of a ‘dead zone’ in the Gulf of Mexico. The dead zone causes problems for the fisheries in the Gulf. It’s believed the dead zone is caused by excess nitrogen on farm fields in the Midwest that’s washed to the Mississippi River and then to the Gulf. A government task force has determined that if the flow of nitrogen into the Gulf can be cut by 30 percent, the size of the dead zone can be reduced. The Great Lakes Radio Consortium’s Lester Graham reports… a new study predicts a 30 percent reduction won’t be enough to make a difference:

Transcript

The government has been working with agriculture, environmentalists and scientists to
come up with a way to reduce the size of a ‘dead zone’ in the Gulf of Mexico. The dead
zone causes problems for the fisheries in the Gulf. It’s believed the dead zone is caused
by excess nitrogen on farm fields in the Midwest that’s washed to the Mississippi River
and then to the Gulf. A government task force has determined that if the flow of nitrogen
into the Gulf can be cut by 30 percent, the size of the dead zone can be reduced. The
Great Lakes Radio Consortium’s Lester Graham reports… a new study predicts a 30
percent reduction won’t be enough to make a difference:


The idea that fertilizer used on a corn field in the Midwest can cause a ‘dead zone’ in the Gulf of Mexico
is hard to fathom. But when you realize that all or parts of 31 farm states drain into the
Mississippi basin, it becomes a little easier to understand. Excess nitrogen causes a huge algae
bloom in the Gulf. When the vegetation dies, it decays on the bottom and bacteria feed
on it. The huge expanse of bacteria depletes the oxygen.


Nancy Rabalais is a professor with the Louisiana Universities Marine Consortium. She
says most life under the water needs that oxygen to survive.


“The oxygen is depleted in the water column so that the fish and shrimp, anything that
can swim, leaves the area. All the indicators show that it’s gotten much worse since the
1950’s to present, and that’s consistent with the increase in nitrogen in the Mississippi
River.”


Since 1985, Rabalais has been measuring the size of the dead zone every year. The zone
ranges in size from about 2,000 square miles to about 10,000 square miles.
That’s about the size of Lake Erie.


Jerald Horst is a biologist with the Louisiana Sea Grant. He says it’s hard to know the
exact impact on life under the sea…


“Very difficult to say ‘Gee, this year the shrimp
production is down somewhat because of hypoxia,’ or whether the shrimp production is
down somewhat because of a host of other environmental factors.”


But the fear is the hypoxic zone could stop being a dead zone that shrinks and grows
– and one year disappeared altogether… and instead become a permanent dead zone where nothing would ever live. That’s happened in a few other places on the globe such
as the Black Sea. It’s not clear that the same kind of thing can happen in the Gulf, but
signs are ominous. Horst says upwellings of oxygen-starved water near the shore after a
storm used to be very, very rare. Lately, they’ve become more and more frequent. He
says it means the problem is getting worse.


There’s still a lot of debate about whether the dead zone in the Gulf is a serious problem.
But, at this point, most agricultural agencies and farm groups have stopped disputing the
science and whether their nitrogen is causing the problem. Now they’re trying to figure
out the best and cheapest way to deal with it.


The government task force that’s working on the problem has arrived at an Action Plan;
the task force has determined the amount of nitrogen getting into the Mississippi River
needs to be cut by 30 percent to reduce the Gulf zone by half in ten years.


Donald Scavia has been working on the problem. He was involved in the debate when he
was a senior scientist with the National Oceanic and Atmospheric Administration. He’s
retired from NOAA and now directs the Michigan Sea Grant. From his office at the
University of Michigan, Scavia explained how the task force arrived at the figure.


“We agreed to a 30 percent reduction because it was similar to what was done in other
places, probably acceptable to the community and will head us in the right direction.”


After arriving in Michigan, Scavia started research to determine if a 30 percent reduction
would do the job. Using three very different computer models, Scavia and his team
learned that they could actually predict the size of the dead zone from year to year…


“From that analysis, that not only looked at the size of the zone, but actually looked at
potential inter-annual variability caused by changes in climate, changes in weather say
that probably 35 to 45 percent nitrogen load reduction’s going to be needed to get to that
goal in most years.”


Scavia’s study was published in the journal Estuaries.


A 35 to 45 percent reduction is a much tougher goal than the 30 percent the task force is
recommending. As it is, states were planning massive artificial wetlands and extensive
drainage programs to soak up excess nitrogen before it got to the tributaries that fed the
Mississippi River. They also planned to get farmers to reduce the amount of nitrogen
they’re using. That’s a tough sell for a couple of reasons. First of all, it would have to be
voluntary because nitrogen use is nearly completely unregulated. Second, farmers
often use what they call an insurance application of nitrogen… they use a little more than
is actually needed to get a good crop, because nitrogen is relatively cheap. The excess
often ends up washed into ditches and streams and creeks and rivers… and finally to the
Mississippi and the Gulf of Mexico’s dead zone. So… cutting nitrogen flow into the
Mississippi by 30 percent was a huge task. Cutting nitrogen by as much as 45 percent… well… you can imagine…


For the Great Lakes Radio Consortium, this is Lester Graham.

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ACTION PLAN NOT ENOUGH TO SHRINK GULF ‘DEAD ZONE’ (Short Version)

  • Small shrimp fishers are concerned about the Gulf of Mexico 'dead zone' because shrimp can't survive in the oxygen depleted water. (Photo by Lester Graham)

A new study predicts the government’s plan to reduce the size of the ‘Dead Zone’ in the Gulf of Mexico won’t be strong enough to make a difference. The Great Lakes Radio Consortium’s Lester Graham reports:

Transcript

A new study predicts the government’s plan to reduce the size of the “Dead Zone” in the Gulf of
Mexico won’t be strong enough to make a difference. The Great Lakes Radio Consortium’s
Lester Graham reports:


The Dead Zone in the Gulf is believed to be caused by excess nitrogen used by farmers in the 31
states that drain into the Mississippi and ultimately into the Gulf of Mexico. The Dead Zone
causes problems for the fisheries in the Gulf. A study published in the scientific journal,
Estuaries, predicts that an Action Plan put together by a government task force might not
go far enough. Michigan SeaGrant director Donald Scavia used computer modeling in the
study…


“What we tried to do here is take three different, very different models and ask the same question
of those models to try to get an answer.”


The answer was the same… the government task force plan to reduce the amount of nitrogen
reaching the Mississippi River by 30 percent is not enough. The models indicated a 35 to 45
percent reduction is needed to shrink the Dead Zone by half in the next ten years.


For the Great Lakes Radio Consortium, this is Lester Graham.

Related Links

Lake Levels Low Despite Rain

Even though it’s been a rainy summer, the shipping industry, boaters and beachgoers are still dealing with low water levels on the Great Lakes. The Great Lakes Radio Consortium’s Rebecca Williams reports:

Transcript

Even though it’s been a rainy summer, the shipping industry, boaters and beachgoers
are still
dealing with low water levels on the Great Lakes. The Great Lakes Radio
Consortium’s Rebecca
Williams reports:


All the rain this season has raised hope for an end to low water levels. But Lakes
Michigan,
Huron and Superior continue to be much lower than average for the fourth year in a row.


Frank Quinn is a hydrologist with the National Oceanic and Atmospheric
Administration. He
says rain is not the only factor affecting lake levels. Temperatures and
evaporation also affect
them. Quinn says the recent rain has helped, but more rain is needed.


“We’ve averaged for the last year about 90% of our normal precipitation…we still
haven’t had
enough continuing rainfall to bring the levels back up to what their long-term
averages would
be.”


Rain has helped raise the lower lakes, Ontario and Erie, but NOAA’s 6-month outlook
shows low
levels continuing on the upper lakes through early spring.


For the Great Lakes Radio Consortium, I’m Rebecca Williams.