When bacteria levels get high, county health departments close the beaches. The latest news of a beach closure is on Lake St. Clair:
A week after the Macomb County Health Department gave the all-clear message to swimmers at Memorial Park Beach in St. Clair Shores, the beach has again been deemed unsafe for swimming. The department issued a no-swimming advisory today for the beach because of high E. coli levels Blossom Heath in St. Clair Shores remains under the no-swimming advisory because of its E. coli levels, as it has been since May 26.
County health departments issue the warnings and closures, and the state keeps track of them.
The Michigan BeachGuard System has a map with red flags marking closures and advisories.
Currently, there are 15 advisories or closures at public beaches around the state - that's 15 out of 1,211 public beaches.
"High bacteria levels" is the reason for most (if not all) of the closures. When E. coli bacteria readings are high, counties will close a beach or issue an advisory.
E. coli bacteria are all around us (they help us digest food) and most are harmless. But there are some nasty ones. See O157:H7 or the new kid of the block O104:H4 (welcome O104:H4! ... not really).
The higher the overall E. coli count (good and bad), the more likely it is that you'll run into the bad bugs, so beaches get closed.
The reasons for the high bacteria levels are often listed as "unknown."
Pollution from sewage plants, runoff from farm operations, old leaking septic systems can be possible culprits. Some researches think bird poop from gulls and geese can lead to high counts. And even more interesting, some think E. coli might have an ecology of its own - blooming here and there for reasons we don't exactly know.