INTRO: The Great Lakes are changing fast. Last week several dozen scientists met at Wayne State University to try to figure out why. Most of the changes are bad. So many of Michigan’s problems are lack of awareness or lack of courage by politicians. But as Michigan Now’s Chris McCarus reports, even the scientists don’t know what action to take.
Zebra mussels first invaded the Great Lakes on ships from Eastern Europe in 1988. Scientists found this out. And they know where to find them now.
“You could basically walk across Lake Michigan on a bed of mussels. They have completely carpeted the lake bottom in some places. That has a dramatic effect on what’s going on: the water column and the exchange between the sediments beneath. You can imagine if the mud beneath is now covered with a layer of mussels the communication between the mud and the water is different. The mussels are concentrating nutrients and affecting everything.”
Dr. Ruth Blake is a professor at Yale University. She’s developed tools to study cells and enzymes of phosphorous.
“There are changes in the oxygen levels. Usually when you get just below the surface of the sediment a lot times due to microbial activity in the waters all the oxygen is used up. Like in your fish tank when you have too much gravel. It becomes anoxic. When that changes it causes minerals and particles to dissolve and release things. One thing that’s released is phosphorous.”
Before humans clogged the lakes with pollution and invasive species, the mud and the water grew healthy fish. Current was normal then and still is now. But zebra mussels have never been. These foreign organisms are excreting waste and sending it all the way up to the surface. Then when you’re out fishing or swimming algae’s green slime covers you and hundreds of square miles. Dr. Ruth Blake says:
“Think of it as fertilizer. That’s basically what phosphorous is: fertilizer. The reason you have too much algae is you have too much fertilizer. Too much of a good thing.”
It’s good for farmers because it makes their crops grow. Scientists and environmentalists have been blaming farmers whose fields run off into the Saginaw River, The Fox River in Green Bay and the Maumee River in Toledo. Then they empty into the lakes. But be careful says Dr. Ruth Blake:
“You don’t want to blame the algal bloom on the farmer over here if it’s really internal recycling of phosphorous that’s coming from the lake bottom.”
Blake normally studies the Atlantic Ocean. She’s interested in the Great Lakes because they’re like a movie being shown in fast forward. So much to learn.
“Things that take place on the scale of 1,000 years in the ocean take place on a scale of 1 year in the Great Lakes.”
She grew up in Detroit. So Blake also has personal reasons for getting into the fight.
“Nature is changing OK. We get game changers like these mussels that have dominated so heavily. So there’s still plenty to learn.”
“I would say we’re out of balance. Yes. Did we conclude that we’re out of balance in the Great Lakes? It’s changing rapidly in so many ways. We don’t understand how that affects things like carbon cycling and nutrient cycling.”
University of Wisconsin professor Galen McKinley was still revved up after the 3 day conference at Wayne State ended. She’s from the Department of Atmospheric and Oceanic Sciences. McKinley mentioned ocean acidification. It could be killing fish.
“The overall issue of acidification is out there in the Great Lakes because we’re putting more carbon in the atmosphere. You drive more into the water. That’s shed onto the long term load of the PH but we don’t have very good observations of that.”
Not in the Great Lakes but acid in the oceans is better understood. I asked Dr. Ruth Blake if climate change factors in? She said yes. Climate change is real and it shouldn’t be political.
“I live on the east coast where we have been experiencing slightly different weather and more powerful storms. So you have fewer doubters these days.”
No oceans in Michigan. So no hurricanes. Like Sandy that hit New York last year. Perhaps you have to live through one then come back to the Great Lakes. After that, if there’s any chance of bringing positive instead of negative change…. you’ll have to embrace science.