The three current projects in this focus area aim to improve use of existing technologies as well as develop new methods to detect, prevent and mitigate harmful algal blooms (HABs) and their impacts. This helps to ensure drinking water safety and a healthy environment for lakeshore residents by connecting the dots between many of HABs’ potential causes and effects.
To track the problem where it begins – high up in the Lake Erie watershed – Laura Johnson at Heidelberg University is leading a project that monitors runoff from farm fields farther up in the rivers and streams that bring nutrients and pollutants to the lake. Samples collected from rivers like the Blanchard, which flow into the Maumee and then Lake Erie, will record changes in phosphorus runoff from fields planted with different crops, and after heavy rainfall events, to determine how those factors affect overall runoff.
In addition, the project scientists will analyze water samples to develop a “fingerprinting” method for different types of phosphorus. Looking at different isotopes of oxygen in phosphate – which differ in their atomic weight – may help pinpoint phosphorus that comes from commercial fertilizers instead of other sources, while the molecular structure of dissolved organic phosphorus connects the nutrient to organic sources like manure or wastewater treatment plant discharge.
“Having those two things together, we’re hoping that we can then distinguish different sources of phosphorus,” said Laura Johnson, the project’s lead researcher and director of the National Center for Water Quality Research at Heidelberg University. “The ultimate goal is that we would end up with the ability to collect samples at the ends of watersheds and have some understanding of where that phosphorus came from: what percentage of it is manure, what percentage commercial fertilizer, and so on.”
Two complementary projects in this focus area are developing warning networks for Lake Erie’s western basin, where harmful algal blooms are most common. Tailored specifically for Maumee Bay and Sandusky Bay, the networks provide basin-wide data coverage of bloom-affected areas by streaming data from water quality buoys and sensors positioned near water treatment plant intakes to an online database.
“The main goal of the project was to create a harmful algal bloom early warning system for the use of water plant managers who use water from Lake Erie,” said Tom Bridgeman, principal investigator on the Maumee Bay project and associate professor at the University of Toledo. “Along with placing a buoy upstream of the Toledo water intake, we instituted a weekly sampling regime around the water intake and into Maumee Bay so that if there was a toxic bloom approaching the intake, we could give them a heads-up.”
In addition, the researchers are collecting background environmental information such as temperature, sunlight, water clarity, phosphorus and nitrogen levels to better understand what triggers harmful algal blooms, and how changes in water chemistry can cause them to produce toxins.
The early warning system in Sandusky Bay focuses on similar parameters, just in a different part of the lake. Both projects also work with scientists from NASA to match aircraft and satellite observations of Lake Erie algal blooms to actual water quality data. Although satellites cover a larger area, aircraft can provide more detailed imagery of blooms and operate on cloudy days when satellites can’t see the lake, Bridgeman explained. These methods could allow researchers to determine which kinds of algae make up a bloom from remote sensing images instead of having to take boats out to specific sampling locations.
The Sandusky system already demonstrated its potential during the 2015 season. A rapid increase in chlorophyll, a green algal pigment, was detected on July 17, indicating that algae were present at the primary water intake for Sandusky’s Big Island Water Works.
“On that day, there was a lot of chlorophyll that entered the water treatment plant,” said George Bullerjahn, project lead and professor of biology at Bowling Green State University. “However, the parallel phycocyanin (a blue-green pigment found in HABs) sensor was silent, indicating that all the material that entered the water treatment plant was green algae, it wasn’t cyanobacteria. So the plant staff didn’t have to worry about toxicity, but they did have to worry green algae which may have affected taste and odor issues.”
The same warning systems will be deployed in both bays again in future years to reduce the likelihood of future bloom events interrupting water services to residents and tourists, potentially causing large-scale economic damage for the area.
Combining data from river sensors with information from lake buoys will help refine predictive models that can relate weather events to runoff and subsequent algal blooms, giving water managers more time to react to potential bloom events.
“By the end of this project, we will have a good idea of where the optimal sites to place these buoys are and what the optimal number of buoys is,” said Bridgeman. “The Maumee and Sandusky Bay projects each operate one buoy, but if you put the data from all of the buoys in the remote sensing network together, you certainly develop a more comprehensive picture of bloom dynamics in the western basin.
More information about the current HABRI projects is available at ohioseagrant.osu.edu/research/collaborations/habs, where you can also download the 2015 annual report.