Northern US Lakes At Greater Risk For Toxins Due to Algae Blooms, Study Finds

(Photo : Getty Images/Mario Tama)

A recent examination of lake water quality found a considerable increase in the likelihood of toxic algae blooms in northern lakes as a result of climate change.

A finding published in Nature Water shows that water temperatures ranging from 20 to 25 degrees Celsius (68 to 77 degrees Fahrenheit) are most likely to acquire harmful amounts of microcystin, a common algae-produced toxin.

Examined More Than 2,000 Lakes

Researchers were able to anticipate the future production of microcystin, a toxin produced by blue-green algae species, in lakes across the country in a study involving 2,804 lakes in the United States from 2007 and 2017.

As part of an effort to better understand the hazards to water quality posed by climate change, they investigated how water temperature impacts the occurrence and concentration of microcystin.

Their findings point to a northward shift in places prone to algal blooms, particularly in the Great Plains and the northwest United States.

Lakes are frequently used as markers of climate change, but experts warn that the precise effects of warming on microcystin concentrations are unknown.

They propose that the temperature range consistently associated with an increased incidence of microcystin occurrences is between 68 and 77 degrees Fahrenheit.

"It's clear regions with a history of fewer toxic blooms are likely to experience an increase in such occurrences due to climate change," said Ted Harris, co-author of the study and assistant research professor with the Kansas Biological Survey & Center for Ecological Research.

Health Risk

When bodies of water become overwhelmed with nitrogen and phosphorus runoff from agriculture and other human activities, harmful algal blooms occur. These extra nutrients can cause blue-green algal populations to explode out of control.

Microcystin can be harmful to people's health and the environment, as well as pose economic threats to fishing and tourism.

This also impairs liver function and, in rare cases, causes death in wild and domestic animals, including humans. In circumstances of prolonged exposure, it is also categorized as a possible carcinogen.

"In 2014 an algal bloom in Lake Erie led to high levels of microcystin in water intakes, and residents in Ohio and Ontario were instructed not to drink tap water due to risk of exposure," said Julian Merder, co-author of the study.

Merder further explained that the abundance of blue-green algae is expected to rise owing to climate change as they outcompete other species.

However, past field investigations have yielded conflicting findings about these implications for microcystin concentrations.

The researchers hope that these findings will help highlight the substantial threat to safe drinking water, fishing, recreation, and other societal needs in many parts of the United States, as well as the importance of creating management plans to prepare.

Every year, harmful algal blooms cause multimillion-dollar economic losses in the United States due to health hazards, disruptions to fisheries, and a drop in recreational and tourism activities.

The National Oceanic and Atmospheric Administration pledged more than $20 million earlier this month to fund the monitoring and research of toxic algal blooms in US seas and the Great Lakes.