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Lake Erie Algal Bloom Expected to be Smaller This Summer

kevin bunch
Kevin Bunch
Algal blooms on Lake Erie
algal algae blooms western lake erie noaa
Algal blooms on western Lake Erie during August 2015. Credit: NOAA

The 2016 algal bloom on western Lake Erie is forecast to be smaller than the one in 2015 primarily due to reduced nutrient loading from the Maumee River during the March-July period, though it could still end up being large enough to be considered a “bloom of concern,” according to the National Oceanic and Atmospheric Administration.

According to Jeff Reutter, special advisor at Ohio State University’s Stone Laboratory, the harmful algal blooms, or HABs, on Lake Erie can be forecast accurately from the amount of phosphorus loading in the Maumee River during the spring. With a drier spring than the previous three years and no surge of June storms to drive greater river flow into and along the Maumee – as was the case in 2015 – there is less phosphorus in the western basin overall than last year, and less of other nutrients as a whole.

The NOAA office is estimating a severity level of 5.5 for this year, which is based on the size of the HAB biomass in the lake. Any bloom with a severity level above 5.0 is considered a bloom of concern, with the 2015 bloom measuring 10.5 on the NOAA cyanobacterial index scale, making it the largest bloom on record. A bloom between 2-4 on this severity scale is considered “mild” and 0-2 indicates there’s no bloom of note, said Rick Stumpf of NOAA National Centers for Coastal Ocean Science. A more severe bloom is not necessarily more toxic, according to Stumpf. The 2015 bloom was only a quarter as toxic as 2014’s bloom, which measured a 6.5 on the severity scale. The toxin concentrations can also vary in the water column all the way down to the lake bottom.

2016 lake erie algal bloom forecast
The 2016 Lake Erie algal bloom is forecast as a 5.5 on the 10-point severity scale, which measures the size of the bloom. This figure was generated from the results of several different models. Credit: Rick Stumpf

HABs can pose serious health and safety risks. Toledo issued a “do not drink” advisory for its public water supply for more than two days in August 2014 due to cyanotoxins found in the raw and treated water. Cyanotoxins can be dangerously toxic in even recreational contexts. In 2015, Stumpf said, the toxins were measured up to 3,000 parts per billion in the western basin of Lake Erie, and anything above 10 ppb is too toxic for swimming.

According to NOAA, skin contact with the toxins in the blooms can cause rashes, hives and blisters, while swallowing those toxins can lead to diarrhea, vomiting, liver poisoning and neurotoxicity symptoms, ranging from numbness and dizziness in humans to convulsions, excessive salivating and death in dogs. Boiling water or using standard filtration systems won’t remove the toxins from affected water, either. NOAA also advises against going into the water until several weeks after a bloom has disappeared, as it could have simply fallen underneath the surface of the water and the toxins can remain in the water column for days or weeks. NOAA also advises people to be careful about eating fish from the bloom area; while little information is available on how these toxins build up in fish, NOAA suggests avoiding the liver and guts, and cleaning other parts of the fish thoroughly.

Phosphorus has been a known driver behind algal blooms since the 1960s, according to Environment and Climate Change Canada, leading to binational action under the 1972 Great Lakes Water Quality Agreement to bring phosphorus levels down.  This significantly reduced HABs as a major problem on Lake Erie, albeit temporarily. In the mid-1990s HABs started appearing again on Lake Erie due to an increase in the fraction of phosphorus called dissolved reactive phosphorus. Invasive quagga and zebra mussels have played a significant role as well, because they move nutrients closer to the shorelines and thus change the lake’s nutrient dynamics. Lastly, climate change is affecting the delivery of nutrients to streams and rivers that discharge into Lake Erie and water temperature, which affects algal growth rates.

algal bloom samples noaa
A handful of algal bloom samples are being prepared for testing at NOAA’s Great Lakes Environmental Research Laboratory in 2015. Credit: NOAA

 

In February of this year, Canada and the United States agreed on a 40 percent phosphorus reduction target, from a 2008 baseline, to reduce algal blooms on Lake Erie. Each country now has to come up with a domestic action plan by February 2018 to meet those targets, which includes an assessment of environmental conditions, identifying priorities in international monitoring and research, and priority measures to reduce phosphorus loadings. The IJC issued the Lake Erie Ecosystem Priority (LEEP) report in 2014 with a series of recommendations to the governments on how to meet a similar 40 percent reduction.

While the algal bloom forecast may not be as bad as last year’s, that doesn’t mean Lake Erie has returned to health. In its 2014 LEEP report, the IJC recommended controls on septic tank discharges, elimination of most uses of phosphorus lawn fertilizer, and an enforceable plan for both agricultural and urban nutrient load reductions.  More work is needed to reduce nutrient loading and algal blooms for good so that everyone can enjoy a clean, healthy lake. 

kevin bunch
Kevin Bunch

Kevin Bunch is a writer-communications specialist at the IJC’s US Section office in Washington, D.C.

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