Western Lake Erie’s 2018 algal bloom was the 10th most severe on record since the modern era of aerial surveillance began in 2002 and fell short of all scientific predictions, the National Oceanic and Atmospheric Administration said in its seasonal wrap-up issued this morning.
NOAA, the federal government lead agency for seasonal algae predictions and analysis, had predicted a bloom with a severity of 6 on a scale of 10. That was in large part a composite of predictions ranging from 4.9 to 7.8 made by several area universities and other scientific bodies working with the agency.
In the end, the bloom’s severity reached only a 3.6 on a scale of 10. NOAA’s index measures the severity of each bloom, including several factors beyond size. It is based on the biomass over the peak 30 days of each season.
Scientists such as Rick Stumpf, an oceanographer with NOAA’s Center for Coastal Monitoring and Assessment in Silver Spring, Md., have said this year’s bloom was a bit unusual because of its arrival the last week of June, a few weeks sooner than surface scum usually appears.
In its seasonal wrap-up, NOAA said that early arrival “was probably a result of the rapid early warming of Lake Erie, starting at the end of May.”
Drought and near-drought conditions fell over the region in July. Then, NOAA noted, a heavy Sept. 9-10 storm broke up much of the bloom with strong winds over Lake Erie.
“The bloom did not recover, and ended by the first week of October, one of the earliest ends of the bloom we have seen,” NOAA said.
The methodology for making forecasts gets refined each year as more is learned about the science of algal blooms.
“There are inconsistencies in how each model has behaved in the last few years, so that will be considered in how the ensemble will be developed next year,” Mr. Stumpf told The Blade.
He said scientists also are looking harder at the relationships between harmful algal blooms and healthy forms of algae that support the food chain for fish, such as diatoms, and how seasonal wind patterns could come into play.
Scientists “will be reviewing the satellite data against field data to better quantify” the role of stronger and more frequent winds, Mr. Stumpf said.
The seasonal precipitation also was a little different than 2017, when there was a stronger bloom.
Although river discharge and rainfall this year were typical of long-term averages, it was higher in March and April, lower in May and June, and very low in July, NOAA said.
That was almost the opposite of 2017, which had an extremely wet May and July.
Algal blooms of various species have been known to exist in western Lake Erie for several decades, in part because of its warmth, shallowness, and proximity to people. The most heavily populated part of the Great Lakes region is from Detroit to Cleveland.
But whereas the problem used to be poorly or untreated sewage waste, it is now far and away agricultural runoff.
Blooms went away to a large degree after the 1972 Clean Water Act and Great Lakes Water Quality Agreement ushered in the modern era of sewage treatment. They began reappearing in strength in 1995, with NASA providing satellite images from outer space to NOAA on a regular basis in 2002.
Climate change also is seen as a contributing factor, as are effects of invasive species such as quagga mussels.
The lake’s most dominant form of algae today, microcystis, is one of Earth’s oldest living organisms and is on the rise worldwide. It is believed to be about 3.5 billion years old. The planet’s age is estimated at about 5 billion years.
The largest western Lake Erie blooms on record since 2002 were in 2015, 2011, 2013 and 2017, respectively.
First Published October 30, 2018, 8:29 p.m.
