Scientists are predicting that the August-September bloom of harmful algae in the western basin of Lake Erie will be less than 10 percent of what it was last year, said Jeff Reutter, director of Ohio State University's Ohio Sea Grant office and Stone Laboratory in Put-in-Bay harbor.
The lack of spring storms greatly reduced runoff between March and June and as a result, much less phosphorous from farm operations and sewage overflows entered the lake, Reutter said.
High-levels of phosphorous combine with warm weather to create harmful algae blooms that can produce toxins dangerous to swimmers, boaters and fishermen.
While the low phosphorous levels are good news, Reutter said, they are merely buying a year's time to come up with better ways to control farm runoff and sewage discharge.
If there's a normal or wet spring next year, the high levels of algal bloom will be back unless improvements are made, he said.
The dangers of blue-green algae
Lake Erie harbors many forms of algae. The blue-green strain common to the shallow, western basin of Lake Erie is capable of producing a toxin called microcystin, which has been known to kill people in Brazil and pets in the Ohio and other parts of the United States.
Blue-green algae recently reported in the water at Fairport Harbor Lakefront Beach Park would not have been associated with the bloom in the western part of the lake, Reutter said, but any inherent dangers from that bloom are not clear.
While algal blooms can be dangerous, they also can be costly. The City of Toledo spends three to four thousand dollars a day during algal blooms to remove toxins from its water supply, which comes from Lake Erie, said Tom Bridgeman, assistant professor in the Department of Environmental Sciences at the University of Toledo. He, along with Reutter and others, spoke during a webinar in support of this year's bloom prediction.
Algal blooms over the past decade increased sharply in 2008 and remained high in 2009 and 2010, Bridgeman said, but in 2011 the bloom was "off the charts," spreading well into the lake's central basin. Scientists have been saying for several years that the toxic blue-green algae will only worsen on Ohio's inland lakes as well.
This year's bloom should most resemble that of 2007, which was mild.
Scientists are not yet capable of determining where the blooms will occur, but generally speaking, milder blooms do not extend as far east from the lake's western basin where the problem is most severe, said Rick Stumpf an oceanographer with the National Oceanic and Atmospheric Administration, also speaking on the webinar.
In 2009, scientists did begin testing a testing system, however, the Lake Erie Experimental HAB (Harmful Algae Bloom) Forecast System.
Phosphorous the culprit in the past
While great strides were made decades ago to remove phosphorous from Lake Erie, it appears a major reason for the return of large blooms of harmful algae is an increase in the amount of dissolved phosphorous in the lake, said Peter Richards, a Heidelberg University senior research scientist.
The reason for the increase is not clear, but it could have to do with changes in the way farmers fertilize their fields, Richards said.
Farmers aren't tilling their soil as much, which is a good thing because it reduces erosion and therefore sediment runoff, but they appear to be broadcasting their fertilizer on the surface which makes it more likely to run off into the lake.
This year's bloom prediction for western Lake Erie, produced by NOAA with assistance from other organizations, does not apply to smaller inland lakes, Stumpf said.
A study by Heidelberg University shows that the amount of phosphorous that entered the lake during the April-through-June period was about 2.5 percent of last year's amount for the same period.
Meanwhile, a study by the University of Toledo detected concentrations of phosphorous in Maumee Bay at less than 10 percent of last year's levels, Reutter said, while further studies by the Ohio Sea Grant office and NOAA show similar concentrations in the open waters of Lake Erie.