By Dusty Sonnenberg, CCA, Ohio Field Leader, a project of the Ohio Soybean Council and soybean checkoff.
The algal bloom on Lake Erie has garnered much attention since the summer of 2011. Now when the lake turns green, the general public that uses the lake for recreational purposes, and the tourism industry and the media are quick to point the finger at agriculture as the primary contributor to the problem. The Western Lake Erie Basin is fed by rivers that drain nearly 7 million acres of farmland. The Maumee River flows into the Western Basin of Lake Erie. Phosphorus and Nitrogen in the river water are considered a contributor to the growth of the algal bloom each year.
“The harmful algal bloom (HAB) on Lake Erie has been a problem because the lake serves as the primary drinking water source for the City of Toledo. The HAB can produce toxins that can cause liver damage if the concentration is high enough,” said Greg LaBarge, OSU Extension Field Specialist, Agronomic Systems. “The relatively shallow depth of the lake, which going out to the islands is about 24 feet on average, warms quickly and allows the bloom to grow when conditions are right. The bloom floats on top of the water and depending on the wind direction the bloom can blow into where the city’s water intake is located. This is what happened in 2014.”
The Western Lake Erie HAB Early Season Projection provides an estimate of potential cyanobacterial HAB severity. The projected severity depends on input of total bioavailable phosphorus (TBP) from the Maumee River during the loading season (March 1-July 31), and uses a combination of measurements and forecasts of Maumee River discharge from the National Weather Service — Ohio River Forecast Center (through July) and phosphorus loads measured by the Heidelberg University National Center for Water Quality Research.
The National Oceanic and Atmospheric Administration (NOAA) provides forecasts for seasonal blooms of cyanobacteria (blue-green algae) in Lake Erie, typically from July to October when warmer water creates favorable bloom conditions. Western Lake Erie has been plagued by an increase of HAB intensity over the past decade. These blooms consist of cyanobacteria or blue-green algae, which are capable of producing toxins that pose a risk to human and animal health, foul coastlines, and impact communities and businesses that depend on the lake.
NOAA and the National Centers for Costal Ocean Science (NCCOS) and partners now forecast a smaller than average cyanobacterial HAB in western Lake Erie this summer, with a severity of ~3 and a potential range between 2-4.5. They expect the bloom to be less severe than last year (severity of 6.8). This year’s bloom has the potential to be the lowest in 16 years, since 2007 when it was reported at a severity of less than 1.
This spring has been dry, with low phosphorus loads into the lake, with most of the load occurring in March. July may see more normal rainfall, which could increase the bloom severity to 4.5. The severity is based on the quantity (biomass) of the bloom over a sustained 30 day-period.
Cyanobacteria is not currently detectable by satellite, by satellite or otherwise, in western Lake Erie. Clouds and smoke has obscured the satellite imagery since June 2. No toxin data currently available.
The mainly dry weather pattern in spring and early summer slowed the flow of water systems within the Western Lake Erie Basin, causing lower amounts of nutrients to be transported from the watershed. This proves that weather and climate have the biggest role in reducing phosphorus load into Lake Erie.
“In past years, heavy rainfall events made it impossible to take measures to keep nutrients in place and hampered spring field work,” said Jordan Hoewischer, director of water quality research with Ohio Farm Bureau. “This spring, too little rain may cause nutrient deficiencies in corn and soybean crops as those nutrients may not have been as readily available to the plant, typically utilized by the crop after a normal rain event. It shows how important the amount of precipitation is for farmers to grow a successful crop and what too little or too much rain, which is beyond the farmer’s control, can mean for the potential of algal blooms.”
With the continued funding of the H2Ohio water quality initiative and the growth of the Ohio Agriculture Conservation Initiative certification program, both designed to help farmers employ more and better nutrient management practices, efforts will continue to advance across Ohio.
This is great news for those planning to enjoy Lake Erie over the Fourth of July holiday. For boaters, beach enthusiasts and anglers alike, the water quality will be the best it has been since 2007 and hopefully will stay that way through the remainder of the summer season. NOAA will release the final algal bloom statistics for 2023 in September.