An algal bloom contaminated with toxic bacteria shocked Toledo in August 2014, poisoning the city’s Lake Erie drinking water and forcing the city of 400,000 people to drink bottled water for three days.
Three years later, scientists are taking action to stay a step ahead of the harmful blooms, monitoring the algae and bacteria from outer space, from land, and in the water, with a new arsenal of high-tech tools and research projects.
Over the past decade, blue-green algal blooms, which sometimes turn toxic, have become an annual summer plague on Lake Erie. Some produce microcystin, a bacteria more poisonous than cyanide that can sicken or kill people, fish, birds, dogs and livestock. Even non-toxic blooms can suffocate fish, kill plants and deplete oxygen in the water, causing huge dead zones.
Bloom size does not always correlate with its risk to public health, however. So scientists must employ a battery of testing techniques to track the toxicity in Lake Erie, said algal bloom expert Rick Stumpf, an oceanographer at the National Oceanic and Atmospheric Administration.
Researchers at NOAA introduced an underwater robotic laboratory this summer, which sits at the bottom of Lake Erie where it collects water, testing the levels of toxins, and transmitting the results remotely within four hours. Previously, test samples obtained by working out of a boat took a day or two to obtain results. Two more robotic labs are expected to be dropped into the lake soon.
NOAA also launched a new weather satellite this summer, the Copernicus Sentinel-3, that is beaming more accurate pictures of the bloom back to Earth, providing the power to detect blooms one-tenth the size of those previously detected, Stumpf said.
Other researchers are testing drones on Lake Erie to see if digital images they capture can be effective in monitoring the algae blooms. Already in use on the lake are buoys that measure algae in the water.
The public health risks from low-level exposure to cyanobacteria in drinking water or recreational waters are relatively unknown, however, as are the possible long-term affects of eating fish from algal bloom waters. Research is underway at the U.S. EPA and at Ohio State University, the University of Akron, Kent State University, Heidelberg University, Bowling Green University, the University of Toledo and other schools as part of the Harmful Algal Bloom Research Initiative.
Studies at Ohio State include:
Searching for a more environmentally friendly way to reduce microcystin in lake water and water treatment plants by testing the effects of viruses on the cyanobacteria. One virus is known to destroy its toxic effects;
Finding better ways for the Ohio EPA and Division of Wildlife to measure microcystin in fish caught in Lake Erie. In 2015, six of 73 fish showed detectable levels of microcystin in muscle tissue. In 2016, microcystin was found in 14 of 65 fish. The levels detected were generally very low, leading researchers to surmise that eating Lake Erie fish during the bloom season would not pose a risk to human health;
Working with 56 farmers in the western Lake Erie basin to collect data about the effects of crop selection, cover crops, wetlands restoration, fertilizer application, and other soil management practices on phosphorus runoff and water quality. The researchers also are using the models to see which of these changes are likely to lead to a 40 percent reduction in phosphorus runoff.
Invasive species also have contributed to the proliferation of harmful algal blooms. Quagga and zebra mussels, which arrived in Lake Erie during the 1980s, filter micro-nutrients and plankton, allowing more sunlight for algal bloom growth and leaving less food available for young walleye and yellow perch. The mussels also concentrate phosphorus in their feces, which can be stirred up during storm events to feed the toxic algal blooms.
Mussels, unfortunately, do not feed on blue-green algae.
Many of the algal bloom and invasive species studies are funded by the Great Lakes Restoration Initiative, a $300 million federal program that the Trump Administration has proposed scrapping. Ohio’s congressional delegation has pledged to protect the program, however, and a 2018 budget proposal is working its way through Congress that would preserve the entire $300 million budget.
Removing toxic pollutants from Lake Erie has been a battle for almost a half-century, but the harmful algal blooms that have plagued the lake since the mid-1990s pose a new challenge.
The Clean Water Act helped to address phosphorus, mercury and PCBs pouring out of substandard sewage treatment plants. New federal regulations helped to rescue the lake by the mid-1980s, turning the once-polluted body into the Walleye Capital of the World, and sparking a tourism industry that brings in $14 billion a year.
But over the past decade, dissolved phosphorus has returned to the lake, the majority from agricultural runoff from fertilizers and manure. Most of the algal bloom-feeding nutrient comes from the Maumee River watershed in the Western Basin near Toledo.
“This is much more than an Ohio and Lake Erie problem,” said noted Lake Erie scientist Jeff Reutter. “It is a national and world problem.”
Reutter is co-chair on a team of scientists from Ohio, Michigan and Ontario who struck an agreement to reduce phosphorus runoff by 40 percent by 2025. He is convinced it is a goal that can be met. But it won’t happen without a combined effort from government-financed environmental programs, research, education and productive agricultural reforms, he said.
Some algal-producing factors are beyond human control, though, such as the weather. A dry spring last year, for instance, helped to produce one of Lake Erie’s smallest algal blooms in a decade. This year’s rainy spring has brought predictions of potentially the third-largest bloom on record — although so far the bloom has been normal and concentrated in the far western basin.
Climate change also has brought warmer temperatures to the lake, causing the blooms to form earlier and faster, to grow larger and thicker, and to last longer into the fall.
A climate assessment report released in January, by the National Academy of Sciences found the recent decades have been the warmest in the past 1,500 years. Average annual temperature increases of as little as two degrees can have a harmful environmental effect, fostering algal bloom growth by producing longer heat waves and more intense rainstorms, the report said.