Researchers are predicting possibly toxic algae will form in western Lake Erie this summer, but are expecting the bloom to be less severe than previous ones that contaminated drinking water, officials say.
National Oceanographic and Atmospheric Administration scientists expect this summer's bloom to measure a 6 on the severity index but could range between 5 and 7.5. This is smaller than last year's, which ranked as an 8, but larger than the mild bloom in 2016, which had a 5.5 ranking.
The severity index (on a scale of 0 to 10) is based on the harmful algae over a period of time during a bloom. Contamination in 2014 left more than 400,000 people in Toledo and parts of southeastern Michigan unable to drink tap water for two days.
The largest blooms recorded were in 2011 and 2015, which ranked at a 10 and 10.5 respectively. That 2015 bloom covered an area the size of New York City, officials said.
One factor contributing to the severity of algae blooms is phosphorus runoff from nearby farms using fertilizers. This gets into the lake and feeds the existing plants.
Lake Erie has seen an average amount of rainfall, but warmer than normal temperatures in June, starting the blooming process two weeks early, said Laura Johnson, director of National Center for Water Quality Research at Heidelberg University in Ohio.
"It’ll be noticeable, significant, but won’t be the worst we’ve seen," Johnson said. "Having started sooner than usual, we think it means it's just going to be a longer bloom, not worse. However, we can't forecast how toxic and exactly where."
NOAA researchers say it's too early to tell how much phosphorus could go into the drinking water but are developing tools to predict the toxicity of the chemicals.
“Research efforts across the state have helped our communities prepare for blooms of this size, from developing new technologies to keep toxins out of our drinking water to assessing the human health impacts of harmful algal bloom toxins,” said Dr. Christopher Winslow, director of the Ohio Sea Grant College Program. “While continued efforts are still needed to reduce nutrient runoff and therefore the size of future (harmful algal blooms), Lake Erie residents and visitors will still be able to safely enjoy much of the lake during bloom season.”
The harmful bloom of cyanobacteria, which occurs when colonies of algae and plants that live in the sea and freshwater grow out of control, has become a national concern, said Dr. W. Russell Callender, assistant NOAA administrator.
“NOAA continues to develop tools that provide early warning systems for harmful algal blooms, which help visitors and the community make better informed decisions about recreation activities," Callender said. “The resources and services the lake provides drive our economy and we’ll keep working with our partners to bring the most accurate forecasts for the region.”
Blooms affect not only drinking water but the marine ecosystems and economy, especially for coastal communities dependent on income generated through fishing and tourism, Johnson said.
"When it comes to lake economic hardship, boat captains taking people fishing saw a drastic loss in 2015," said Johnson. "The effect on the aquatic life is small and we see them often move because of the bloom from western to center... but this is only a few months of the year."
Ohio Gov. John Kasich also signed an order Wednesday that sets out to create new regulations on farms to cut the amount of fertilizer feeding Lake Erie’s huge algae blooms.
Ohio, along with Michigan and the Canadian province of Ontario, have pledged to significantly cut how much phosphorus enters the lake by 2025. But, farm groups have been pushing back against calls for increased regulations, saying it’s not clear what approach will solve the algae problem.
NOAA plans to issue bulletins twice a week during the bloom season providing a three- to-five day forecast.