What Lies Beneath

Something Is Blooming on the Suncoast, and It's Not Pretty

If it's not red tide, what's that awful smell? The answer is dapis pleousa, another type of algae.

By Emma Moneuse May 29, 2024

<em>Dapis pleousa</em> is an algal bloom caused by warm temperatures and an increased amount of nutrients in our watershed—and it stinks.
Dapis pleousa is an algal bloom caused by warm temperatures and an increased amount of nutrients in our watershed—and it stinks.

Have you noticed big, brown globs of muck floating in our local waters recently? Well, there’s a name for it: it's a bloom of Dapis pleousa algae, caused by warm temperatures and an increased amount of nutrients in our watershed. The blooms pose a threat to marine life, coastal ecosystems and humans alike. Not only does Dapis algae emit a sewage-like stench as it starts to decompose, but exposure to the bloom can cause skin problems, respiratory trouble, itchy eyes, throat irritation and other ailments. (Sound familiar?)

Dapis starts to grow near the bottom of the bay, attaching to seagrass and other structures before floating to the surface. The bloom has begun to dominate certain seagrass ecosystems and is noted as a potential cause for the loss of seagrass in the Tampa Bay area.

The local environmental protection group Suncoast Waterkeeper has been tracking the pervasive bloom over the past five years. According to its observations, Dapis, along with red tide, has increased in intensity over that time due to an influx of nutrient pollution. Previously known as Lyngbya, Dapis, like all algae blooms, needs a handful of ingredients to grow: sunlight, heat and nutrients like nitrogen, phosphorus and iron.

Those nutrients enter our waterways at abnormal levels mostly because of human behavior. In its May newsletter, Suncoast Waterkeeper states that “rapid coastal development, boating and groundwater are likely sources of nitrogen, phosphorus and iron contributing to the bloom.”

“If all three ingredients that cause algae to bloom are increasing, we can therefore expect an increase in algal blooms in the future,” says Suncoast Waterkeeper executive director Abbey Tyrna.

There are ways to limit harmful algal blooms like Dapis and red tide, starting with the amount of nutrients we allow into our waterways. With recent rollbacks in wetland and buffer protections in Manatee County and a recent Supreme Court decision to cut back on wetland protections across the country, the fight for our water does not come without challenges.

“Manatee County just struck from its comprehensive plan several objectives regarding safeguarding wetlands for water quality and wildlife benefits,” says Tyrna.

Due to a new law signed by Gov. Ron Desantis, the changes made by Manatee County are nearly impossible to fight—even when they are not in the public’s or the environment’s best interest. The law, Senate Bill 540, requires people who challenge comprehensive plan amendments to pay the legal fees of their opponents, who are typically wealthy developers who have shown an interest in building on as much land as possible.

While this may sound grim, there are still many ways individuals can make a lasting impact for positive change. “Advocate for stricter water quality rules,” advises Tyrna. “Participate in elections and know how your local and state representatives voted on water quality issues. If you have reclaimed water coming from a wastewater treatment plant that does not have advanced treatment, then do not fertilize. There is fertilizer already in your irrigation water. Only fertilize when your grass needs it.”

Other suggestions from Tyrna? “Attend local government comprehensive planning meetings, rezoning meetings and any other local meetings to use your voice to protect more wetlands and slow the pace of development,” she says. “Finally, do whatever you can to reduce your carbon footprint.”

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