Beaches along Lake Michigan are closed when E. coli bacteria gets too high. But a nasty critter found on the bottom of the lake might help keep the beaches open. E. coli gets into the water and on beaches through stormwater runoff and sewer overflows. But those are a relatively small part of the problem. Most of the fecal bacteria comes directly from visitors. “It can be deposited directly from skin shedding from people on the beach. It can also be deposited by wildlife defecation, and diapers,