Algae is part of nature, and despite the association people typically have with it, algae aren’t all bad! However, too much of anything is usually a bad thing, and that includes algae. Here in Florida, algae is common in all types of bodies of water, from ponds to estuaries. Algae blooms peak in the late summer, so I wanted to take this time to talk a little bit about it, in the next installment of Florida 101: Algae.
What are algae?
Algae is a term for many types of photosynthetic organisms that are not plants. There are a wide range of types of algae, from single-celled phytoplankton to multi-celled macroalgae that can either float or be attached to the seafloor. You can learn more about the differences between macroalgae and seagrass in the Indian River Lagoon in this blog I wrote last year.
Phytoplankton are single-celled, free-floating algae, and there are thousands of species that live in both fresh and saltwater environments. Phytoplankton are important because they form the base of the aquatic and marine food webs and they produce over half of the oxygen that we breathe! Phytoplankton need sunlight and nutrients (especially nitrogen and phosphorous) to survive and grow. When they have the right conditions, they can reproduce rapidly, leading to an algae bloom.
Algae blooms
There tends to be more algae growth in the summertime because there is more sunlight. Summer is also our rainy season, meaning that more nutrients are flushed into bodies of water with runoff. When there are excess nutrients in a system coming from sources like fertilizer on lawns or seepage from septic systems, algae blooms can take over lakes, canals, or estuaries. These blooms are visually unappealing, may clog waterways, and block sunlight to other organisms, like seagrass.
Once the algae start to die, bacteria break down the algae and all the oxygen in the system is used up. If the waterway has low oxygen levels (hypoxia), then fish may die because they do not have enough oxygen.
How can you help prevent algae blooms?
Reduce the amount of nutrients that enter the waterway! Do this by fertilizing only when necessary and not before heavy rain and growing native plants that require less fertilizer. If you live on a canal or other body of water, leave a natural buffer between your lawn and the canal. Allow native vegetation to grow here, which will help absorb any nutrients and lawn clippings before they are able to enter the waterway. You can learn more about best practices when it comes to soil and fertilizer from UF here.
If you have a septic system, make sure it is maintained so that it works as efficiently as possible. If you have the opportunity to switch to a sewer system, understand that these systems will help improve water quality because they are designed to remove nutrients from the water, which septic systems are not. When it comes time to replace your septic system, you may want to consider options like Aerobic Treatment Units, which are able to remove more nitrogen than a traditional septic system. If you would like more information on septic systems, check out the UF septic systems FAQ page.
Here are some types of algae you may hear about in Florida:
Red tide: caused by a single-celled phytoplankton called Karenina brevis. When there is a large bloom of this phytoplankton, it can cause a reddish color in the water. It also has negative health impacts for marine life and humans and can lead to fish kills, fisheries closures, and respiratory irritation in humans. Red tide primarily affects the gulf coast. Use the Red Tide Current Status website to see the red tide status around the state of Florida, and learn more in this blog article from my colleague Megan.
Bioluminescent algae: the Indian River Lagoon is home to a single-celled phytoplankton called Pyrodinium bahamense. This phytoplankton produces a neurotoxin that can cause paralytic shellfish poisoning in humans, and so oyster and clam fisheries are closed when the levels are high. The algae also produce bioluminescence, and in the summer months the waters of the Indian River lagoon glow when disturbed by water movement. I have a whole blog on these Creatures from the Glowing Lagoon if you would like to learn more about our local bioluminescent plankton!
Sargassum: a macroalgae that is naturally occurring in the ocean and can wash up on our beaches. In some places in Florida and the Caribbean there have been high levels of sargassum on beaches, which causes issues due to smell and negative effects on tourism. Some sargassum on the beaches is natural and good because can help trap sand and helps to grow our dunes. It is also very important out at sea, as it provides habitat for juvenile sea turtles! You will likely hear a lot about sargassum in the news – learn how to dispel the myths.
Cyanobacteria aka blue-green algae: is actually a photosynthetic bacteria, not a true algae. It grows well in low-oxygen environments and a variety of salinity levels, so can be found in fresh and brackish water environments. Some blue-green algae can produce toxins that have negative impacts on the environment and human health. The Florida Department of Health recommends that individuals and pets should not drink or swim near water where a bloom is present. My colleague Mike wrote a recent blog all about cyanobacteria, so if you would like to learn more about these blue-green algae, keep reading here.
Florida 101 blog series
If you haven’t already, be sure to check out the rest of the Florida 101 blog series:
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