The National Oceanic and Atmospheric Association has released a forecast predicting a moderate to above moderate Harmful Algal Bloom (HAB) in west Lake Erie this summer.
The bloom is of a specific species of algae, known as cyanobacteria, or blue-green algae. This specific algae species can release a toxin into the water that is harmful to human and animal health. Large algal blooms can also consume a lot of dissolved oxygen.
This year, the bloom is expected to be between 4.5 and 6 on the severity scale. The scale measures the total biomass of the algae in the lake. Currently, the bloom has an approximate area of 160 square miles. This year's forecast is similar to last year's measurement of 5.3.
This level of HAB is above what scientists would like to see. The normal range of a bloom is under a 3 on the severity scale.
The largest HABs that have been recorded in Lake Erie were in 2011 at a 10 and 2015 at a 10.5.
Dr. Chris Winslow, director of the Ohio Sea Grant and Stone Laboratory, said the reason that the blooms happen is due to excess nutrients in the water, caused in part by runoff from agriculture and waste water.
“This organism, this harmful algal bloom, this cyanobacteria, is naturally occurring in the lakes. It’s always been here, evolutionarily,” Winslow said. “It’s just because excess nutrients are coming into Lake Erie that these things are growing at a higher rate.”
Winslow also said that climate change can also play a factor in larger HABs.
“Climate change, in this part of the county, is increasing spring rain events. And so rain events is what carries [nutrients] from the land into the lake, to ultimately grow these organisms.”
Winslow added, “Climate change for this part of the country also has elevated summer time temperatures. And what that means is that this organism typically grows in the hot summer. So if you have more rain, meaning more nutrients, and you have higher temperature, which is basically ideal conditions for this organism, it’s creating kind of the perfect storm to grow this thing.“
The bloom doesn’t just affect people and animals on the lake.
Winslow said that part of the response to an HAB is to warn water treatment facilities. “About 11 million people get their drinking water from Lake Erie. So if this species is out there and it is producing toxins, that water will be drawn into a water treatment plant before it is sent out to customers.”
NOAA is currently warning those near or on the lake to be aware of the bloom and to avoid areas with algal scum. Cyanobacteria and its toxins can be highly concentrated within scum.
The growing season for cyanobacteria is July through September.