Pond Scum: The Good, the Bad, and the Sludgy

Globs of algae the size of human heads floated around like something out of a B-movie on MST3K. It was unnerving to bump into one of them. I can handle swimming with eels…but I find it creepy to swim with severed head-shaped algae clusters. When I arrived at my little local lakeside beach in southern Maine, I thought I was lucky because no one else was there in 90-degree heat. Then I realized the beach was vacant because of the algal bloom. An algal bloom is a concentration of cyanobacteria. Strange Wetlands covered types of algae blooms, including blue green algae, in an earlier post (2010).

In the Great Lakes region this summer, some communities are seeing algal blooms, including the Eastern parts of Lake Erie. Algal blooms turn the water a bright scummy green. Some of the vegetation washes ashore in clumps, deterring beach goers but not always causing beach closings.  However, NOAA has recently issued a prediction that western Lake Erie should see a lesser algal bloom this summer. This is good news.NOAA, partners predict mild harmful algal blooms for western Lake Erie this year. A presentation will be held on algal blooms and the “Lake Erie Dead Zone” by an aquatic biologist in Cleveland Heights on July 25th.  For more information about the Lake Erie Dead Zone, visit EPA’s webpage. But this year’s bloom on Lake Erie is likely to be only one tenth the size of the bloom that occurred last year.

Last year, Lake Erie’s harmful algal bloom was visible from space (2011). In fact last year’s algae blooms in the Great Lakes were touted as the ‘worst since the 1960s,’ something akin to the comics of “The Creature from the Black Lagoon.” The Natural Resources Defense Council presented analysis of Ohio beach closings and algal bloomsand on New York beaches for Lake Ontario and Lake Erie with monitoring data collected in 2011. Full report here.

What’s the issue this summer? Not all algae, or “pond scum,” is created equal. Some amount of algae is a normal part of the ecosystem but too much of the wrong types are harmful. A Great Lakes native algae called Spirogyra is thriving on the conditions caused by invasive zebra and quagga mussels. The result is a sludge-like mat of green algae that washes up on beaches along Lake Michigan and other lakes. Another green alga, Cladophora, increased because of the zebra mussels, and both types of algae wash ashore in thick mats, which rot, stink and harbor E. Coli, Salmonella and other pathogens. The stench from the beach muck is comparable to manure. See video, “All Washed Up: Lake Michigan’s Algae Challenge.” For a fact sheet on Harmful Algae Blooms & Muck: What’s the Difference (Michigan Sea Grant), click here. For more about the relationship between algae and zebra mussels, see Changes in the benthic algal community and nutrient limitation in Saginaw Bay, Lake Huron, during the invasion of the zebra mussel (report, 2002).

Another serious factor this summer is drought, which is occurring in a large part of the country. For instance in Wisconsin, the hot weather has caused harmful blue green algae blooms in Lake Winnebago and Tainter/Menomin lakes, where there is a history of blooms, but the harmful algae is also showing up in lakes where it previously did not occur. They are facing a similar problem to that in Lake Michigan with the zebra mussels and Cladophora, warned to be harmful to boaters and swimmers. The US Fish & Wildlife Service has found dead waterfowl, most likely killed by botulism, in Wisconsin lakes this year. For a past FWS report on waterfowl and botulism in the Wisconsin lakes, click here.

Algal blooms are probably not at the top of the list of issues concerning those keeping an eye on the Farm Bill developments—but this is one of the reasons why the Farm Bill’s Conservation Title is so crucial to the protection of wetlands and water resources—including the Great Lakes. See Farm Bill Conservation Programs Are ‘Essential for Great Lakes Restoration’

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