Lake Erie in North America has been taken over by toxins-producing algae, photos taken from space show. It has turned a lurid green as algae blooms across its surface, with people being warned to stay out of the water.
The blue-green algae was covering roughly 320 square miles of the lake on the day the photo was taken on August 13. It exploded to over 660 square miles by August 22, pictures taken by the OLI-2 (Operational Land Imager-2) on the Landsat 9 show.
According to NOAA, the algae started blooming on June 24 this year, the earliest algal bloom in Lake Erie for over 20 years.
The algae is also known to release toxins and so people have been warned not to enter the waters. “While toxicity varies throughout the bloom, toxins concentrate in surface scums during calm weather. People and pets should not swim in areas with scum,” NOAA noted in a report in July.
The dominant species in the bloom is Microcystis aeruginosa, which is a species of cyanobacteria, also known as blue-green algae. It is responsible for the release of harmful algal blooms (HABs) in freshwater systems worldwide. M. aeruginosa is known to produce a toxin called microcystin, which is harmful to both humans and animals. The toxin primarily affects the liver.
These algae create concentrated areas of toxins in the water bodies as cells aggregate into large floating mats or scums on the surface of water bodies.
NOAA’s Great Lakes Environmental Research Laboratory said the toxins in the first week of discovery measured at “concentrations above the recreational limit”.
Any kind of contact with microcystin, either through drinking water, eating contaminated fish, or a water activity can cause nausea, vomiting, diarrhoea and skin irritation. In extreme cases, it can cause liver damage. Animals can die due to poisoning.
Algal blooms also affect marine life adversely by reducing oxygen levels in the water during decomposition. This creates dead zones where aquatic life is unable to survive.
Fertilisers, manure, wastewater discharges and stormwater cause nutrients like phosphorus and nitrogen to enter water. These nutrients have been strongly linked to microcystis blooms.
“Nutrient input from the Maumee River is the dominant driver of HAB variability from year to year,” Brice Grunert, a professor in the Department of Biological, Geological, and Environmental Sciences at Cleveland State University, said in a NASA Earth Observatory statement.