Satellite images show massive algal bloom on Lake Okeechobee

The National Oceanic and Atmospheric Administration is monitoring what they believe to be a large cyanobacteria bloom on Lake Okeechobee.

According to Oceanographer Michelle Tomlinson of the NOAA National Ocean Service, they have been monitoring satellite photos of the lake since the start of June.

Ms. Tomlinson shared the following information about the images.

• A series of satellite images acquired on June 12, 20, 21, and 24 show the progression of cyanobacterial bloom in Lake Okeechobee.

• On June 12, about 3 percent of lake area was covered by cyanobacteria blooms. Most of the blooms appeared along about a mile off the eastern shore.

• On the June 20 image, the bloom was observed to be covering about 49 percent of the lake surface area mostly in the south-western quadrant of the lake and some bloom accumulation along the north-western shore.

• There was a decrease in bloom areal extent on June 21 of about 22 percent, where the bloom was observed along the eastern part of the lake. The decrease was likely due to wind mixing cyanobacteria cells down into the water column and not the disappearance of the bloom. These cells float back to the surface when winds subside.

• The latest image from June 24 shows the maximum cyanobacterial bloom extent observed in the month of June so far.

• The bloom was observed to be covering almost the entire lake area excluding a narrow stretch along and about 6 miles off the eastern shoreline. Pronounced bloom accumulation was observed along the eastern shoreline.

“The algorithm we developed for the imagery is showing cyanobacteria blooms,” she explained. “So it is separating out the cyanobacteria from any other background algae in the lake. There may be some non-harmful phytoplankton mixed in there but what you are seeing is the concentration of the cyanobacteria.”

According to Dee Ann Miller of the Florida Department of Health, “Some – not all – blue-green algae can produce toxins that can contribute to environmental problems and affect public health. Little is known about exactly what environmental conditions trigger toxin production. Over time, these toxins are diluted and eventually break down and disappear. Persistent blooms are routinely monitored and retested. Because you cannot tell if algae is producing toxins by looking at it, the Florida Department of Environmental Protection (DEP) coordinates with the water management districts and the Florida Fish and Wildlife Conservation Commission to routinely sample observed and reported algal blooms and test for algal identification and toxin levels.”

Results posted by FDEP as of June 25 found no toxins in the samples collected last week. Earlier this month, very low levels of toxins of less than one microgram per liter were reported in samples from locations just off Lake Okeechobee’s east shore. The World Health Organization considers levels under 10 micrograms per liter as safe for recreational contact.

Samples were collected from various areas around the lake on Monday. Testing takes about four days.

NOAA is also tracking algae blooms in other areas of the country such as Lake Erie and the Gulf of Maine.

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