As warmer weather arrives and we approach the main recreation season on Lakes Oconee and Sinclair, many of us are spending more time near and in the water. You’ve probably noticed how the lake really “greens-up” this time of year … and perhaps sometimes how a lake’s color can even be an unusually bright green?
Those green lake colors occur due to the naturally occurring presence of planktonic algae. These microscopic algae are the essential base of the aquatic food chain in lakes. Here is some additional information that you may find helpful during your time around the lakes this summer.
Algae FAQ’s for Georgia Power Lakes
What are Algae?
Algae are microscopic organisms found throughout the world in all types of freshwater and saltwater habitats.
Why are Algae important?
They serve as the base of the food chain in all aquatic ecosystems. In freshwater, they provide food for fish and bugs which in turn feed other fish and aquatic animals. Algae also produce about 40-50% of the oxygen we breathe.
Why do algae make the water look green?
Just like grass or the leaves on a tree, algae contain a green pigment in their cells called chlorophyll which enables them to perform photosynthesis. When lots of algae are present, that green pigment can be seen making the water look green.
What are other types of algae?
Cyanobacteria, or “blue-green” algae, are among the oldest organisms on earth. Blue-green algae contain green pigments for photosynthesis and help make lake water look green. Cyanobacteria are also vital to the health of an aquatic ecosystem.
What is an algae bloom?
When conditions are right, algae grow fast and become noticeable. This can make the water turn a rich pea-soup green or even look like spilled green/blue paint. This condition, known as a “bloom”, can also form a thick surface film or thick green mat. It can sometimes also have an unpleasant smell.
What causes an algae bloom?
The primary environmental trigger for an algae bloom is an increase in nutrients such as Phosphorus and Nitrogen. Temperature increases and bright sunny days in the Spring can also trigger blooms. Certain species of blue-green algae use extra nutrients more efficiently which leads to faster growth.
Where do the extra nutrients come from?
Nutrients in water primarily come from rainfall runoff within a watershed. A watershed is the land area where water drains and carries that runoff to a nearby lake, river, or stream. Watershed runoff may come from urban areas, rural agriculture fields or pastures, or residential lawns and golf courses in addition to natural land. Fertilizers and naturally occurring nutrients wash into lakes and streams which then provide the fuel for algal blooms.
Does water temperature matter for an algae bloom to occur?
Typically, warmer water (late spring through early fall) combined with increased nutrients create favorable conditions for algae blooms. Many species of algae grow faster at higher temperatures; however, some species can tolerate cooler temperatures.
Are algae blooms harmful?
Blue-green algae are not always harmful, but some can produce toxins. Not every algae bloom produces toxins, and it can be difficult to identify if a bloom is toxic. Typically, a water sample would have to be collected from the area of the bloom and sent to a special laboratory to test for toxins.
What are some harmful effects of blue-green algae toxins?
Effects of exposure to algal toxins vary greatly and range from simple skin rash or skin irritation to possibly throat swelling, respiratory problems, headaches, or eye irritation. The effects of exposure to the toxins depend on the amount and type of exposure and to the physical condition of the person.
How do I avoid contact with an algae bloom?
Avoid swimming in or around a thick green mat or layer on the water surface, and avoid ingesting the water from incidental contact. Also keep your pets out of the water if you see this condition.
Who do I contact if I have questions about the health effects of exposure to blue-green algae?
Contact your healthcare provider. They can provide more information about any possible health risks as well as diagnose and treat any symptoms.
What can I do to help prevent algae blooms?
Limit the amount of fertilizer you use on your lawn. Keep fertilizers off driveways and sidewalks. Maintain a buffer of native plants around shorelines that intercept and absorb nutrients.
Who do I contact if I see an algae bloom?
Contact your local Georgia Power lake office and report your observations.