“North America’s Dead Sea” is the nickname Lake Erie was given in the 1960s. Nearly 64 million pounds of phosphorus flowed into the lake each year from factories, sewer systems, fertilized farms and lawns. The nutrient pollution caused massive algal blooms which were often not only toxic themselves, but caused enormous dead zones in the lake, killing off fish and other marine life. The U.S. and Canada spent over $8 million in the 70s and 80s to upgrade lakeside sewage plants and dramatically cut phosphates in household detergents. And gradually, the lake began to come back to life, fish populations recovered and the lake’s $10 billion tourism industry rebounded.
Now, scientists worry, Lake Erie is dying again. Gradually increasing levels of phosphorus runoff over the years are the primary culprit, but researchers warn that climate change is also playing its part — making a bad situation much worse.
In 2011, close to 20 percent of Lake Erie was covered in a layer of pea soup colored, scummy algal bloom that despoiled beaches all summer long and clogged boat motors well into the fall. The algae was microcystis, a form of blue-green algae that produces liver toxins, which cause numbness, nausea, vomiting, and even liver failure, especially in pets. The bloom was blamed on torrential spring rains that hit the area fast and hard, breaking local precipitation records and practically power-washing fertilizer off nearby corn and soybean fields and into the lake.
These sorts of intense precipitation events have been increasing since the 1970s as the climate changes, explained Molly Woloszyn, Illinois-Indiana Sea Grant program extension climatologist, during an online presentation on climate change and Lake Erie algal blooms, sponsored by The Ohio State University on Tuesday.
“More frequent and intense storms will lead to more phosphorous runoff and more severe blooms,” she said.
The duration of the blooms will also increase. This summer’s bloom, which was the second worst on record after 2011, began in July and lasted until almost November — a full month longer than past blooms. Lake temperatures stayed above 59 degrees Fahrenheit — the threshold below which the algae cannot survive — right until the end of October.
The Ohio Phosphorus Task Force released a report last week recommending a 40 percent reduction in all forms of phosphorus that ends up in northwest Ohio’s rivers and streams that feed Lake Erie. The recommendation is at present, just that, a recommendation and is in no way compulsory. Farmers in Indiana and Michigan would need to be persuaded to get on board as well as many of their farms are part of the same watershed.
New farming practices, known as no-till farming, which are designed to help prevent soil erosion are believed to be among the biggest contributor to the steady increase of phosphorus coming into Lake Erie since the 90s. The method dispenses with the need to plow, which has the unintended consequence of keeping fertilizer in the upper layer of the soil where it can easily be washed away by a storm.