Lake Erie’s algal bloom fading

With Lake Erie’s 2014 harmful algal bloom fading away in the lake’s cold water, a scientist who studies the blooms is looking back on his forecast for this year.

It turned out to be accurate, said Richard Stumpf, an algal bloom forecasting expert with the National Oceanic and Atmospheric Administration.

Lake Erie still has a harmful algal bloom, but it’s shrinking and fading fast. If past years are a guide, it should be gone by November, Stumpf said.

NOAA’s latest “Experimental Lake Erie Harmful Algal Bloom Bulletin,” issued on Oct. 14, said conditions are good for a decline in the bloom, produced by the MIcrocystis bacteria.

“The water temperature has dropped below 59 degrees, the point where Microcystis effectively stops growing and rapid decline will occur,” the bulletin says.

Stumpf said NOAA hasn’t issued another bulletin since then because cloudy skies have prevented scientists from getting a good look at Lake Erie’s surface from the satellite photos the agency depends upon.

The cold water, high winds and cloud skies are all bad news for the algal bloom, so Stumpf doubts there will be much left when he finally gets a good look.

Meanwhile, he’s looking back at the forecast he issued in early July at Stone Laboratory on Gibraltar Island near Put-in-Bay. It’s become an annual event at Stone Lab.

This year, Stumpf introduced a numerical scale. If the massive 2011 algal bloom was a “10,” and 2013’s big bloom was an “8,” the bloom in 2014 should be a 5 or a 6. That’s turned out to be pretty close, Stumpf said Wednesday.

Jeffrey Reutter, Stone Lab’s director, said the introduction of a numerical scale was a good step. Numbers are easier for people to understand than telling people the algal bloom will be “significant,” Reutter said.

The annual forecast will return in early July 2015, after scientists have had a chance to study the runoff produced by rain from March to June 2015, Reutter said.

So, if this year’s algal bloom was mild, why did algal bloom toxins force about half a million people on the weekend of August 2 to avoid using Toledo’s water supply?

There were several factors, some of which are still being studied, Stumpf said.

One is that the harmful algal bloom arrived earlier than usual, he said.

Another is that northerly winds drove the algal bloom to the shore and currents pushed the bloom near the bottom of the lake, where the water intake is.

“There’s probably some element of bad luck,” he said.

One unknown factor is whether the toxicity level of the algal bloom varied during the summer. That’s being studied, with a report due before next summer, Stumpf said.

The scientists can see how thick the algal bloom is, but they want to find out if the amount of green sludge is linked to the amount of toxin being released into the water. The level of toxin, and if it changes during the summer, is an interesting issue, he said.

“That’s different from the esthetic point of view, the fact that it’s disgusting and they need to get the muck out of the water,” Stumpf said.



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