♦   Blue-green algae are not algae at all, but types of bacteria called cyanobacteria that are normally present in many lakes.

♦   This type of bacteria thrives in warm, nutrient rich water.

♦   Cyanobacteria are aquatic and photosynthetic, that is, they live in the water, and can manufacture their own food.

♦   Because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see.

♦   When conditions are right, the bacteria can grow quickly forming “blooms.”

♦   However, blooms aren’t always large and dense and can sometimes cover small portions of the lake with little visible algae present.

♦   An algal bloom is the overgrowth of microscopic algae or algae-like bacteria in fresh, salt, or brackish waters.

♦   Algal blooms occur when algae multiply very quickly. Blooms can form in waters that are rich in the nutrients the algae need to grow, such as nitrogen, phosphorous, and iron. Warmer waters may also help algae grow quickly to form blooms.

♦   Blooms may become more frequent as the earth warms and the levels of nutrients in our waters increase.

♦   An algal bloom can look like foam, scum, mats, or paint floating on the surface of water. Some blooms are not visible at the water surface.

♦   Water bodies with an ongoing bloom may look blue, green, brown, yellow, orange, or red.

♦   When organisms in a bloom die and decompose, they can release unpleasant odors (like the smell of rotting plants).

♦   The Stick Test 

   ◊   If your lake or pond has a mat of green material floating on the surface, the stick test can help determine what it is.

   ◊   With the gloves on, push the stick into the surface mat and slowly lift it out the water. If the stick comes out looking like it has been dipped into a can of paint, the material is likely blue-green algae. If the stick comes out with green strands like hair or threads, the material is probably filamentous green algae, which may be a nuisance but is not a health hazard.

♦   You can become sick if you swallow, have skin contact with, or breathe in airborne water droplets while swimming, boating, waterskiing, tubing, bathing, or showering in water that has harmful algae or if you drink water that contains algal toxins..

♦   Pets are vulnerable to HABs, too—dogs in particular, because they’re most likely to swim in or drink the water.

♦   There are three classes of cyanotoxins, and each type has different effects:

   ◊   neurotoxins, which can cause neurological damage;

   ◊   peptide hepatotoxins, which can cause serious damage to the liver; and

   ◊   dermatotoxins, which can cause skin irritations and respiratory issues.