Canada geese are often blamed for causing high levels of bacteria in lakes because they're seen in the area. Due to the high cost, no one tests the bacteria to find out if it's pathogenic (disease causing) in nature and DNA testing is rarely conducted to link the bacteria to a specific species, human or non-human. Instead, they blame the geese to justify having them removed. Please read the article below (Bacteria in sand baffles scientists) to unravel the myth behind the claims.
WHAT IS E-COLI?
The following paragraph is taken from the pages of the CDC:
Escherichia coli (abbreviated as E. coli) are a large and diverse group of bacteria. Although most strains of E. coli are harmless, others can make you sick. Some kinds of E. coli can cause diarrhea, while others cause urinary tract infections, respiratory illness and pneumonia, and other illnesses. Still other kinds of E. coli are used as markers for water contamination—so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate the water is contaminated. It does get a bit confusing—even to microbiologists.
Bacteria in sand baffle scientists
Water health indicators might not be reliable
BY JOHN MYERS
Duluth News Tribune
The bacteria that has forced the closure of many Great Lakes beaches in recent years may not be coming from people, geese, diapers or sewage spills after all. It may be from the sand.
A Central Michigan University report published Wednesday in the Journal of Great Lakes Research confirms that E. coli can live and thrive in beach sand without a warm-blooded host.
It has been widely believed that E. coli could come only from the guts of warm-blooded animals, and that, if found in the environment, there must have been a recent source of excrement from one of those animals. While not necessarily a threat to human health, E. coli has been used as an indicator of other pathogens in the excrement, such as viruses, that could make people ill.
But Elizabeth Alm, a Central Michigan University microbiologist, says E. coli is growing in Lake Huron sand with no contribution of fecal matter from people, birds or animals.
E. coli even survived winter in the sand and during summer expanded to high numbers for several weeks with no new source, Alm found in her research.
"The source of these bacteria may be resident in the sand," Alm reported.
The finding means scientists and public health officials need to find a new indicator for harmful pathogens in the water, Alm and others say. It also could mean that more dangerous organisms may be thriving in the sand.
"Geese and gulls and diapers may still be sources of some fecal matter and some E. coli, but we clearly can have E. coli without any of them," Alm said. "We need to do a lot more research to see what else may be naturalized in the sand."
It's not clear what the original source of the sand-dwelling bacteria was, or even if there was an outside source.
The findings echo research in the Twin Ports by University of Minnesota-Duluth biologist Randall Hicks. Hicks, who is using DNA fingerprints to trace the sources of local bacteria, has found in recent summers that bacteria seemed to be naturalizing in the sand and sediment of the harbor.
Wind and waves are the culprits that disrupt the bacteria in the sand and bring it in contact with people. Beach monitoring programs then pick it up in water samples and post beaches as closed.
That's happening every summer now along the waterfront of the Duluth-Superior harbor where E. coli problems are chronic and some waterfront areas remain posted most of the summer for people to stay away.
"They (bacteria) seem to do just fine in the sand and sediment, out of the sunlight, if nothing disturbs them. We don't know how long they've been down there or how they got started," said Heidi Bauman, who leads the Minnesota Pollution Control Agency's Lake Superior beach monitoring program. "It backs up what they found in Chicago recently where the bacteria in the sand were higher than in the water. So they dug out the sand and brought in new sand and within a few weeks the bacteria levels were right back up."
Alm's tests on Lake Huron were conducted in the "swash" area where waves wash onto the sand — also the area where people have the most contact with sand and water.
"It means we're going to have to come up with a better way of determining if the water is safe or not," Alm said. "Right now, though, E. coli is the best indicator we have."