GREEN BAY, Wis. (WBAY) - Dead zones in the Bay of Green Bay are not improving, according to a new study by a researcher at UW-Milwaukee.
A dead zone occurs when blue-green algae blooms suck oxygen out of the water and create areas with virtually no aquatic life. It's been a documented problem on the Bay of Green Bay over the past 20 years.
"The dead zone conditions are really driven by excess nutrients coming into the bay and a lot of those are coming from agricultural run-off. And we actually here in the lower bay, Green Bay, receive about one-third of all the nutrients for all of Lake Michigan," says Julia Noordyk, Wisconsin Sea Grant Water Quality Specialist.
Noordyk says the dead zones are moving.
"We're a shallow bay and it's a very dynamic system, so things can change from day to hours to weeks based on weather conditions, currents, winds and circulation," she tells us.
Noordyk contends climate change is leading to more rain, causing more run-off into the bay. However, she says there is hope.
There's a growing trend in agriculture now to create healthier soils and reduce top soil and manure run-off.
"The best thing we can do is work on keeping agricultural soil on farmers fields," Noordyk says. "We don't want America's best top soil ending up in lower Green Bay."
Researchers say more than 80 percent of nutrient loads entering the bay from streams and rivers occur during 14 days each year when there's a heavy rain or snow melt.