The dos and don’ts of algae strandings
The Town of Fort Myers Beach works very hard to maintain a safe and clean environment for our residents and visitors alike. No matter how hard we work, some events are difficult to clean up after and manage. For example, our Public Works staff spends many hours every year cleaning up after people who leave trash all over the beach after celebrations like the Fourth of July and New Years Eve. Our Public Works staff is also the first to respond to unforeseen events such as storms and algae washing up onto our beach. Cleaning up after people is often easier since we can anticipate when and where the trash will be left on the beach and what we have to do to clean it up. Cleaning up after algae wash up events (called “strandings”) is far more difficult since we have to balance many factors including tides, waves, beach stability, the type of algae, and environmental protection.
Fort Myers Beach and Sanibel are still feeling the effects of the rainy season from 2013. Last summer, extraordinary rains pushed enormous amounts of fresh water and nutrients from the Caloosahatchee River watershed and from Lake Okeechobee. Not all of these nutrients washed away with the tides and some lingers in our local waters. These nutrients act like fertilizer and fuel algae growth (this is the reason local governments have very tight restrictions on fertilizer use). As this algae grows, it occasionally breaks off and moves with the tides and waves “drifting” along the bottom like a tumbleweed unless it reaches something that stops its progress like a beach. If the tides and waves don’t pull it back out to the Gulf, then it becomes a “stranding” event. Town staff monitors our beach daily and often on multiple tidal cycles and note when and where anything including wrack and trash wash up on the beach.
It is important to realize that algae, shells, and other natural materials washing onto our beach are normal and helpful to our beach and is called the wrack line. The wrack line contains nutrients that help dune vegetation grow and hold sand on the beach. The wrack line also has inorganic parts that beak down and helps form and build the sugar white sand we treasure here on Fort Myers Beach. Wracks lines also form a unique ecological community on the beach. This community is important to migratory birds such as the Red Knot as feeding areas. Globally, Red Knot populations have plummeted more than 70 percent over the past 30 years and their annual migrations from Argentina to the Arctic Circle are partially fueled by these feeding stopovers in wrack lines.
When our staff monitors wrack lines and stranding events, we have to keep in mind that a normal wrack line is important, however, we also realize that too much wrack can be unsightly and, well, smelly. If the wrack gets too thick and begins to become an aesthetic issue, then we begin to analyze the wrack. With input from research scientists at the Sanibel-Captiva Conservation Foundation and coordination with the City of Sanibel, we can often identify the type of algae and have a better understanding and where it came from and what to expect.
For example, the latest stranding occurred two weeks ago when red drift algae began to strand in the center of the island. This algae was most obvious at low tides when the receding water left it on the beach. This event was also characterized by two driving factors: waves and tides.
There was very little wave action that week so the algae never really moved. We also had our very high and low “spring” tides which revealed more of the beach on low tides making the situation appear worse than it was. On high tides, there was very little algae on the beach at all. We also found that the algae was spread very thin and, if we had attempted to remove it, we would have removed tons of sand. We don’t want to damage the beach, which is our most important natural resource while attempting to clean algae.
As it turns out, the event from two weeks ago resolved itself naturally as waves pushes much of the algae offshore and what remained on the beach quickly bleached and broke down. However, if the algae had piled up, our Public Works Department would have acted to remove as much as possible in a manner that does not harm the beach.
We will continue to monitor beach conditions and will act whenever algae strandings reach excessive levels. When we do act, it will be with the utmost care to maintain the natural beauty of our beaches. Protection of the environment, beaches, sea turtles, and shorebirds are a priority and our goal is to balance this protection with a beautiful, visitor friendly beach, which is why we limit beach raking and always seek to protect our wrack line.
If you have questions about wrack, sea turtles, shorebirds, or management of our beaches please contact the Town’s Environmental Sciences Coordinator, Keith Laakkonen at 765-0202 (ext. 136) or at Keith@FortMyersBeachFL.gov
-Keith Laakkonen is the environmental sciences coordinator for the Town of Fort Myers Beach