Madison in Bloom: Blue-Green Algae Hits Home

This was originally posted here. The Bloom Begins It was a hot, sunny day and Steve Carpenter couldn’t believe the view from his second-floor office on the shoreline of Lake Mendota. As far out as he could see from his perch in the Hasler Laboratory for Limnology – west to the UW-Madison Rowing team’s boat house and east all the way to the Edgewater Hotel and James Madison Park – the calm, still water looked just like teal-blue paint. It was a massive bloom of toxic blue-green algae and “it is the worst one I’ve seen in a long time,” says Carpenter, director of the UW-Madison’s Center for Limnology. “It’s been many, many years since I’ve seen one this bad.” In fact, the bloom that hit Madison last Friday, June 16th, was one of the largest blooms to mar Mendota’s shoreline since the summers of 1993 and 1994, he says. Like this summer, those summers were also marked by “classic” conditions for an algae bloom. Lake Mendota sits in a landscape dominated by agriculture. And some elements of this agriculture, especially the manure produced by dairy operations and synthetic fertilizers used to help corn and soybeans grow, is loaded with phosphorus. This wouldn’t be a huge problem if things would just stay where they’re put. But this spring and early summer has been marked by not only higher-than-average rainfall (we’re about 35% above normal precipitation levels) but also by intense storm events of 2 inches or more of rain. All of this rain, especially the “gullywashers,” carry tons of phosphorus-laden soil into nearby creeks and streams, where it eventually ends up in our lakes and...