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Using Satellites to Track Lake Erie Harmful Algal Blooms | Ohio Sea Grant

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Using Satellites to Track Lake Erie Harmful Algal Blooms

4:20 pm, Thu August 30, 2018 – Satellite imagery is routinely used to track harmful algal blooms in Lake Erie, and Stone Lab is participating in a project to make analysis of those images more accurate

Stone Lab’s Algal and Water Quality Lab is collaborating with The University of Toledo, Bowling Green State University and NOAA researchers to support the Ohio Environmental Protection Agency (Ohio EPA) in data collection for a potential designation of Lake Erie as impaired. The current impaired status is based on satellite data, which only measures how much cyanobacteria are present in the water, not how toxic a bloom is.

“It’s very difficult to judge impairment based on toxin data because blooms and their toxins can be extremely patchy, but satellite data can quantify bloom biomass over the entire lake with one image,” said Dr. Justin Chaffin, Stone Lab’s research coordinator. “The satellite flies over almost daily, whereas the toxin data is collected less frequently from relatively few locations. So we’re going to sample 12 sites once a week, which will add to the data sources from water treatment plants and the Ohio EPA nearshore monitoring program.”

Over the two years of the project, that additional data will give agencies and water managers a better idea of algal toxin concentrations in Lake Erie throughout the year.

The project will also help the satellites that monitor algal blooms with quantifying the scum that builds up on the water’s surface when there are lots of cyanobacteria – the blue-green algae that make up most harmful algal blooms – in very calm waters. In that situation, the satellites’ sensors can get saturated so they no longer register actual algal concentrations beyond a certain level.

“The satellite does a good job from clear water to a little bit green to very green, but then once the cyanobacteria are at the surface and it’s just a floating mat, it doesn’t know how thick that scum is, whether it’s 1 centimeter or 10 centimeters thick,” Chaffin explained. “So we’re going to try to find that threshold where the satellite saturates, and then if we give that data to the NOAA team that creates the algorithm for analyzing the satellite images, they should be able to figure out how to correct their scum measurement data.”

ARTICLE TITLE: Using Satellites to Track Lake Erie Harmful Algal Blooms PUBLISHED: 4:20 pm, Thu August 30, 2018
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Christina Dierkes
Outreach Specialist, Ohio Sea Grant College Program

As Ohio Sea Grant’s science writer, Christina covers research, education and outreach projects in the Great Lakes for a wide range of audiences. She also helps manage online events like Stone Lab’s Guest Lecture Series.