Wednesday, November 11, 2015

Algae bloom in Lake Erie this summer was worst in recorded history

The National Oceanic and Atmospheric Administration on Tuesday rated the algae bloom that covered Lake Erie this summer as the worst in recorded history, Tom Tory reports for the Toledo Blade. "The harmful algae bloom that spread a carpet of 'dense scum'—the scientific term—over 300 square miles of western Lake Erie this summer was the largest since scientists started measuring the blooms in 2002 . . . NOAA rated the 'severity index' level for this year’s harmful algal bloom at 10.5. That compared with a 10 in 2011, the previous highest year, NOAA’s bulletin said. The index is based on the total biomass in the algae bloom." (NOAA map: Algae on Lake Erie)

"NOAA had predicted an intense, harmful algal bloom in the lake this year because of high rainfall that would lead to heavy discharge from the Maumee River, a major source of nutrients from fertilizer and manure on farm fields and livestock operations," Tory writes. "But the amount of harmful algal bloom biomass was greater than it predicted."

Despite higher levels of algal bloom, toxin levels were lower, Tory writes. Justin Chaffin, research coordinator for Ohio State University’s Stone Laboratory at Put-in-Bay, "said two major cold fronts in September weakened the bloom and caused it to decline much faster than in other major blooms." He told Tory, “The bloom just wasn’t producing a lot of toxin, and the water-treatment plant operators had a better idea of what’s coming into their plant.”

For years scientists "have recommended cutting the amount of phosphorus that gets into the lake to curb the annual algae problem," Laura Arenschield reports for The Columbus Dispatch. In June,
"Ohio signed a compact with Michigan and Ontario, pledging to reduce the amount of phosphorus in Lake Erie by 40 percent by 2025." Ohio Environmental Protection Agency director Craig Butler said the agency is preparing a voluntary plan to reduce the amount of phosphorus coming from Ohio into Lake Erie, to meet the 2025 target.

"NOAA’s announcement on Tuesday renewed calls that Ohio pursue a federal impairment designation for the lake," Arenschield writes. "The designation is credited with helping the Chesapeake Bay fight its own algae problems by reducing the amount of algae-feeding nutrients that flow into the bay. The designation would almost certainly mean tougher regulations over how large livestock farms deal with manure and over how much manure crop farmers put down on their fields as fertilizer. The designation also could free additional federal money to help Lake Erie combat algae." Republican Gov. John Kasich has so far refused to ask for the designation.

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