Concerns are starting to mount about the possibility of another toxic algae bloom in western Lake Erie that could jeopardize municipal water supplies and aquatic life.
Algae blooms are part of the natural life cycle of algae, tiny aquatic plants that live in large colonies which can span tens of miles across. The plants generally start to bloom in June and July as the water warms, and peak in August and September when lake waters are at their warmest.
The satellite picture above was taken on July 28, 2015 by the Operational Land Imager (OLI) on Landsat 8. The bloom is visible as swirls of green in western Lake Erie near Sandusky, OH, Leamington, ON and Pelee Island.
Earlier in July, NOAA scientists predicted that the 2015 season for harmful algal blooms would be severe in western Lake Erie.
The bloom will be expected to measure 8.7 on the severity index with a range from 8.1 to potentially as high as 9.5.
This is more severe than the last year's 6.5, and may equal or exceed 2013, which had the second worse bloom in this century.
'This is the fourth seasonal harmful algal bloom outlook for Lake Erie that NOAA has issued,' said Holly Bamford of NOAA.
Blooms in this basin thrive when there is an abundance of nutrients (many from agricultural runoff) and sunlight, as well as warm water temperatures. Harmful algal blooms can affect the safety of water for recreation, as well as for consumption (as was the case in Toledo, Ohio, and southeast Michigan during a 2014 bloom).
On July 30, 2015, drinking water was reported to be safe in these areas.
The dominant organism in the Lake Erie bloom is Microcystis, a type of freshwater blue-green algae that produces a toxin harmful to humans. If consumed, Microcystis can cause numbness, nausea, dizziness, and vomiting and lead to liver damage, and in rare cases, it can be deadly.
Last year, on August 2, 2014, environmental monitors for Toledo and surrounding towns in northwestern Ohio determined that public water supplies had levels of microcystin toxin that were higher than recommended by the World Health Organization (1.0 parts per billion).
They warned residents not to drink or cook with tap water; boiling is not effective against the toxin. Though the bloom has continued, treatment facilities have since added extra filtering steps (including activated carbon), and public water sources were declared safe again on August 4.