A number of environmentalists are concerned that the growing threat of dead zones, along with proposed budget cuts, will be detrimental to the health of Lake Michigan.
"Dead zones" are a phenomenon generally caused by nutrients — primarily phosphorus and nitrogen — entering a body of water and causing algae to grow. That algae eventually decomposes and uses up the oxygen in the water.
"We call that the dead zone because fish cannot survive. Nothing can survive in an oxygen-depleted water body," said Michael Kraft, a professor emeritus of political science and public and environmental affairs at the University of Wisconsin-Green Bay.
Kraft said that the largest contributing factor to dead zones in Lake Michigan is agricultural runoff.
"Agriculture contributes about 46 percent of the phosphorus load. The biggest part of the problem is essentially the way we use land. In Wisconsin, we’re talking about dairy farms," he said. "There are very large dairy farms where manure, fertilizer treatments and other agricultural treatments … enter the streams and eventually find their way into the Bay of Green Bay in Lake Michigan. "
The problem of farm runoff has been exacerbated by an increase in large dairy farms over the last several decades. According to the Milwaukee Journal Sentinel, Kewaunee County had a 34 percent growth in cattle from 1983 to 2012 and Brown County had about a 20 percent increase during the same time period.
"We have larger dairy farms and we have more cattle in the state. And some of these dairy farms are very large, with about 5,000 cows. It’s difficult and costly to control phosphorus, and that’s essentially what’s causing the problem," Kraft said.
Kraft said that regulation is not a very effective solution to agricultural runoff because there are many different points from which the pollution enters the water. Instead, he hopes that the state provides education to help farmers improve their land practices.
However, he's discouraged by the lack of funds to address this issue.
"I would definitely like the Legislature not to reduce funding for the (Department of Natural Resources) so they can act properly on the issue. If the science staff of the DNR is being reduced and if the enforcement budget is not adequate, I think it is hard to move ahead as quickly as we’d like on some of these solutions," said Kraft.
The additional budget cut to runoff programs will hurt the health of the lakes even more, said Kraft.
"We have an additional problem because there are some budget cuts in the governor’s proposal this year for the two-year budget. It’s about $5.7 million from runoff pollution remedies because of the state’s fiscal situation. So in a way, we’ll be doing even less than we’ve done before, even as the problem is growing," he said.