Tag: oxygen depletion

Ten Threats: Wetlands – Where Life Begins

  • Great Lakes coastal wetlands filter water, give lots of wildlife a place to live and help prevent erosion. These wetlands are also greatly responsible for feeding the fish of the Great Lakes. (Photo by Lester Graham)

The Ten Threats to the Great Lakes were identified for us by experts from all over the region.
Again and again they stressed that the shores and wetlands along the lakes were critical to the
well-being of the lakes and the life in them. Great Lakes coastal wetlands filter water, give lots of
wildlife a place to live and help prevent erosion. But the coastal wetlands are also greatly
responsible for feeding the fish of the Great Lakes. Biologists are finding that when people try to
get rid of the wetlands between them and their view of the lake, it hurts the fish populations.
Reporter Chris McCarus takes us to where life begins in the lakes:

Transcript

We’ve been bringing you the series, Ten Threats to the Great Lakes. One of the
keys to the health of the lakes is the connection between the lakes and the land.
The Great Lakes Radio Consortium’s Lester Graham is our guide through the series:


The Ten Threats to the Great Lakes were identified for us by experts from all over the region.
Again and again they stressed that the shores and wetlands along the lakes were critical to the
well-being of the lakes and the life in them. Great Lakes coastal wetlands filter water, give lots of
wildlife a place to live and help prevent erosion. But the coastal wetlands are also greatly
responsible for feeding the fish of the Great Lakes. Biologists are finding that when people try to
get rid of the wetlands between them and their view of the lake, it hurts the fish populations.
Reporter Chris McCarus takes us to where life begins in the lakes:


(sound of walking in water)


About a dozen researchers have come to Saginaw Bay off of Lake Huron. They walk from the
front yard of a cottage into some tall grass and black mud out back. The coastal wetland is wide
here.


Don Uzarski is a professor from Grand Valley State University. He wants to see just how many
different kinds of microorganisms live in this wetland. He asks a colleague to dip a fine mesh net
into the muck.


“Why don’t you give us your best scoop there…”


The net’s contents are poured into a tray. The water and muck is pushed aside and tiny animals
are revealed. None of them is any bigger than an inch.


“There are a lot organisms right there. That’s a lot of fish food. Lot of water boatmen. We have
scuds swimming through here. We have snails. Probably a bloodworm. I don’t see it. But the
red thing.”


Uzarski says this is a healthy patch of wetland. It’s where Great Lakes life begins.


“The whole community starts here. And we’re talking about everything from the birds and fish
and all the things that people tend to care about more. But without this stuff we don’t have
anything.”


These microorganisms are at the bottom of the food chain. Lake trout, walleye and salmon are at
the top. But this natural order has been disturbed by humans. Only parts of the wetland are able
to work as nature intended. The bugs, snails and worms are supposed to be everywhere here. But
Uzarski says they’re not.


“Look at if we take 20 steps over there we’re not going to find the same thing. It’s gonna be
gone. And where’s that coming from? It’s coming from these disturbed edges. Which were
disturbed by? It was the spoils from dredging out that ditch right there.”


The dredging material is piled along the edge… a bit like a dike. Uzarski says that’s one of the
three main threats to coastal wetlands.


The dikes stop the natural flow of water. Farm and lawn fertilizers, sediment and chemical
pollution are not filtered out when they run off the land. Dikes also stop the water from carrying
food for fish out into the lake… and in the other direction, water can’t bring oxygen from the lake
into the wetlands. They’re at risk of becoming stagnant pools.


A second threat to the wetlands is alien invasive plants. Ornamental plants intended for gardens
have escaped. Phragmites, purple loosestrife, and European water milfoil among others all choke
out the native plants that help make the wetland systems work.


But… the greatest threat to the coastal wetlands is construction. We’ve been building homes,
buildings and parking lots right over the top of some of the Great Lakes’ most critical wetlands.


Sam Washington is Executive Director of the Michigan United Conservation Clubs, the state’s
largest hunting and fishing advocacy group. He says we need healthy wetlands if we want to
keep fishing the Great Lakes.


“If we didn’t have wetlands, if we didn’t have the ability to regenerate the bottom foods in the
food cycle of these animals, we wouldn’t have the big fish that people go out in the Great Lakes
to catch everyday. They just wouldn’t be there.”


Washington says the way to fix the problem is easy… but it will require us to do something that
comes really hard…


“The best thing human beings can do for wetlands, even though we really believe we know how
to fix everything, is just to leave ’em alone.”


Sam Washington gets support from the biologists who tromp out into the wetlands. They say
we’ve got to protect the whole food chain… so we should leave wetlands alone and just let nature
do its job.


For the GLRC, I’m Chris McCarus.

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Ten Threats: Green Lawns, Dead Lakes

  • A blue-green algae bloom. (Photo courtesy of the U.S. Fish and Wildlife Service)

The experts who identified the Ten Threats to the Great Lakes for us
say nonpoint source pollution is one of the worst threats. That’s
pollution that doesn’t come out of a pipe but instead is washed from
streets and farm fields… and lawns. Americans use at least three million of tons
of fertilizer on their lawns every year. But the same compounds that make for a lush,
green lawn can make a stinky, slimy mess when they get washed into lakes and rivers.
Sarah Hulett looks at efforts to limit the amount of lawn chemicals that make their way
into the waterways:

Transcript

In our series, Ten Threats to the Great Lakes, we’ve been looking
at environmental problems affecting the health of the lakes. The Great
Lakes Radio Consortium’s Lester Graham is guiding us through the
issues one-by-one:


The experts who identified the Ten Threats to the Great Lakes for us
say nonpoint source pollution is one of the worst threats. That’s
pollution that doesn’t come out of a pipe but instead is washed from
streets and farm fields… and lawns. Americans use at least three million of tons
of fertilizer on their lawns every year. But the same compounds that make for a lush,
green lawn can make a stinky, slimy mess when they get washed into lakes and rivers.
Sarah Hulett looks at efforts to limit the amount of lawn chemicals that make their way
into the waterways:


When newspaper headlines decried the death of Lake Erie in the 1970’s, Americans got
familiar with a new enemy of the environment. Scientists named phosphorus the major
culprit in the lake’s decline. And the reaction went a long way toward cleaning up the
lake: billions of dollars went into upgrades for wastewater treatment plants to reduce
phosphorus from sewage. And phosphate detergents have been mostly phased out of use.


But now that regulators have gotten a handle on the phosphorus coming from the most
obvious sources, they’re left with a much more difficult task: reducing phosphorus from
countless smaller sources that together add up to a lot of pollution.


One of those sources is lawn fertilizer. And Glenn Short says it’s easy to see what
happens when that fertilizer gets washed into the lake where he lives.


(sound of ducks quacking and waves)


“You have this, like, green slime floating all over the top of the lake water. Just pops up
everywhere and it can fill the entire lake surface – especially in the calmer bays. It can be
just miserable for swimming and things like that.”


Short sits on the board of the Lake Sherwood Association, in southeast Michigan. His
neighbors asked him to lobby the township to pass a ban on phosphorus fertilizer to
reduce the algae that takes over the lake in the summers. But he says at first, he was
reluctant to do it.


“I’m like any other homeowner. I don’t want government telling me what to do with my
own property. If I want a really nice lawn, I felt that I should be able to have one.”


But he started doing some research. And he found that enough phosphorus will
eventually kill a lake.


“Over a period of time, you get more and more organic material growing, you kill it off,
you just start filling up your lake. And eventually you have no lake anymore. You just
have a wetland. Well, I like my lake. I mean, I live on a lake. I like to use my lake.”


So Short drafted an ordinance to ban fertilizers containing phosphorus, and his township
board passed it. Several other local governments in the region have also enacted limits or
outright bans. And the state of Minnesota has statewide limits on phosphorus fertilizers.


It’s an approach the landscape industry calls unnecessary.


Gary Eichen is with Mike’s Tree Surgeons in southeast Michigan. It’s a company that’s
signed onto an initiative aimed at environmentally responsible lawn care.


(sound of spreader)


The company uses zero-phosphorus fertilizer on almost all the lawns it treats. Back at the
office, Eichen says the problem isn’t the chemicals – it’s that most homeowners don’t
know how to use them.


“They purchase from a source that is not educated in what the products are. He goes
home and starts going through this giant label on the back, and most of it might as well
be Egyptian hieroglyphics. He has no idea. So he ends up over-applying or incorrectly
applying.”


Eichen says there would be far fewer problems with runoff if homeowners left fertilizing
to the professionals. And he says it’s tough for the experts to stay in business when
there’s a patchwork of local ordinances to regulate chemicals like phosphorus.


But that’s exactly what the Environmental Protection Agency is asking communities to
do. Brad Garmon of the Michigan Environmental Council says that kind of bottom-up
regulation presents some challenges.


“It’s very difficult to see what’s working and what’s not, and to chart success. And I
know that a lot of the state programs are re-evaluating right now to see if the approach
they’ve been using over the last five or ten years has been working.”


It’ll take at least another five to ten years for Glenn Short to see the results of his
community’s phosphorus ban. The lake he lives on is part of a river system that
eventually dumps into Lake Erie. But he says just like that Great Lake, it’ll be worth the
wait and the effort to see his small lake bounce back to health.


For the GLRC, I’m Sarah Hulett.

Related Links

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

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.

Related Links

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