GREEN BAY - New research shows a dead zone is appearing in Lake Michigan's Green Bay.
A dead zone is an area where little oxygen is present, making it difficult for any living organisms to survive.
Experts say the area could be getting worse, due to phosphorus run-off from farms and other sources.
"We've been studying it since about 2009. It's a large area that covers about 30 percent of Green Bay. It starts about 8 miles from the mouth of the Fox River, and it moves all the way up past Sturgeon Bay," said water resources specialist Tracy Valenta.
The concern is that the dead zone could have a negative impact on the region's fish population.