Next up in our series on Harmful Algal Blooms (HABs):

Blue-Green Algae

Blue-green algae are bacteria are capable of carrying out photosynthesis, they are classified as cyanobacteria. Cyanobacteria are extremely diverse and different species occupy almost all habitable locations on Earth.

Many cyanobacteria are very important to our life on this planet, but some produce toxins – they are collectively known as cyanotoxins.

The cyanobacteria currently a problem for SW Florida are species that grow in freshwater mostly belonging to the genus Mycrocystis, the most common being Mycrocystis aeruginosa.

Mycrosystis aeruginosa is green and creates small gas spaces in its cells that cause it to float on the top of water; blooms look like a green film on the water’s surface.

It thrives in nutrient-rich freshwater, has the ability to readily absorb nitrogen and phosphorus, and rapidly reproduce, allowing it to have large, rapid blooms. Because these blooms float, they shade out other algal species in the water, and monopolize nutrient resources.

The chemical produced by Mycrosystis of principal concern is microsystin. This is a small peptide chain, released upon the death of a cell; it is stable in water, and can persist weeks to months after cell death. There are many identified microsystin variants; they are hepatotoxins, which cause serious liver damage. They are also suspected to affect other organs, interfere with sperm production, and are suspected to be mutagens.

The principal known method of ingestion is by drinking water contaminated with microsystin.

Mycrocystis has been thriving in Lake Okeechobee for some time; releases from the Lake to the Caloosahatchee have ‘seeded’ the river with these algal cells, where they continue to thrive and bloom in the nutrient rich waters.

The good news for our Gulf is that Mycrocystis does not tolerate salty conditions well. The bad news is that they will persist in our estuaries and especially the urban canals within them having intermediate salinities quite well.

Lee County has begun attempts to remove cyanobacteria blooms by skimming them from the surface of canals.

Make your voice heard. Contact your representatives about our water quality issues. 

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