Harmful algal bloom expected again, but how big still unknown

SANDUSKY — Scientists predict a substantial harmful algal bloom in Lake Erie this year but said it's too early to predict how bad it will be.The official forecast for the size of this year's HAB will be issued on July 12, said Christina Dierkes, a spokeswoman for Stone Laboratory on Gibraltar Island, near Put-in-Bay.In past years, the forecast was announced by scientists at Stone Lab. The format for the announcement should be similar to past years, although details have not been announced, Dierkes said.Until July 12, scientists will continue to record the amount of rain producing runoff in the Western Basin of Lake Erie, said Laura Johnson, director of the National Center for Water Quality Research at Heidelberg University.Johnson, who participates in the annual Stone Laboratory forecast, said it's not clear yet if this year's HAB will be fairly mild or fairly severe. That depends on how much additional rain falls in the watershed, she said.The National Oceanic and Atmospheric Administration and Johnson's water quality center at Heidelberg issued an early season projection this week for this year's algal bloom.The bulletin noted "a large uncertainty in bloom severity" and said it could range anywhere from being similar to the 2016 algal bloom, which was unusually mild, to being one of the bigger ones the lake has seen.Johnson said at this point, it doesn't look like a really extreme year one way or the other."By July, we feel confident enough to put out a real forecast," she said.Johnson said the scientists who issue the forecast believe they are getting better at it. The first forecast was issued in 2012.In recent years, the scientists have expanded the number of models they use to put together their forecast, she said.Also, recent forecasts have focused on bioavailable phosphorus, phosphorus dissolved in the lake water that can actually be used for growth by lake algae."The combination of those two things have helped us to be a little bit more confident," Johnson said.Reach reporter Tom Jackson at jackson@sanduskyregister.com and follow him on Twitter @jacksontom.Waves gently roll onto the shore at Nickel Plate Beach in Huron on Friday, April 13, 2018.A NOAA graphic shows the possible range in severity for this year's harmful algal bloom and depicts the size of past blooms. Laura Johnson