Town officials are taking a more aggressive approach to the cleanup of the sargassum seaweed that has been smothering long stretches of the local shoreline.
At its Sept. 13 meeting, the Town Council told town staff to obtain an hourly-rate contract with a contractor for special clean-up projects whenever the sargassum piles up in large quantities. In those cases, the contractor would use equipment to bury the sargassum beneath two feet of sand, Public Works Director Paul Brazil told the council. Sea-turtle nesting activity would be monitored to protect nests and hatchlings.
The council also told staff to extend the seaweed raking to include the North End beach north of Angler Avenue on an as-needed basis. Until now, the town has only raked the Midtown and Phipps Ocean Park public beaches, according to Public Works Director Paul Brazil.
The raking includes some seaweed burial when necessary, east of the mean high tide line. The town cannot remove the sargassum from the beach without a specific environmental permit, Brazil has said.
The annual cost of the expanded cleanup is expected to be $50,000, he said.
“I think we’re being very proactive,” Mayor Danielle Moore said.
This year, the sargassum problem was especially bad on the far North End beach from Angler Avenue up to the Palm Beach Inlet jetty, which traps the seaweed by limiting wave energy, officials said.
The free-floating sargassum has been washing up on beaches in Florida and in the Caribbean with greater frequency since 2011, and especially since 2018, Town Councilwoman Bobbie Lindsay said. Its annual arrival roughly coincides with turtle nesting season, which is March to October.
The seaweed can emit a strong “rotten” odor once it washes onto land and begins to decompose. Rotting sargassum produces hydrogen sulfide gas which can irritate the eyes, nose and throat of people or pets.
The sargassum also presents an obstacle to sea turtle hatchlings who can get trapped in it while trying to make their way into the ocean.
“There are times of the year when we don’t need to [rake] it,” Brazil said. “But during peak times, we [rake] it twice a week and don’t get everything.”
There was some good news at the meeting. The large amount of sargassum that collected on the far north beach late this summer, between Angler Avenue and the jetty, was unexpectedly covered with sand by rougher weather and higher tides earlier this month, Coastal Program Manager Rob Weber said. Weber provided photographs showing the dramatic and welcome change.
The town had won permission from state environmental agencies to bury the sargassum in that area beneath two feet of sand as part of a pilot project. But Brazil said it’s no longer necessary at this point.
Brian Lapointe, a research professor and algae expert at Harbor Branch Oceanographic Institute, was invited by the council to join the sargassum discussion via Zoom.
Sargassum occurs naturally and has been around for eons. But Lapointe and other researchers have found that the warmer climate and nutrients, especially nitrogen that is used in fertilizers, are fueling the excessive blooms of the last 11 years. The nitrogen reaches the Atlantic Ocean through the Amazon, Congo, Mississippi and other rivers.
Lapointe suggested the town monitor the sargassum for possible arsenic and fecal bacteria contamination before burying it. The fecal contamination occurs because of sewage that’s been dumped into the ocean.
If the buried seaweed contains those contaminants, they could leach into the groundwater and become a problem for nearshore wildlife, Lapointe said.
“It’s important to know what you are burying in the sand there,” he said.
Lapointe said Harbor Branch tests thousands of samples of the sargassum from points all around the Atlantic Ocean Basin, and that it could assist the town in monitoring for the contaminants.
Using heavy equipment to remove the seaweed from the beach can contribute to sand erosion, he said. There are places in the Caribbean where they use booms and sea fences to keep the sargassum from reaching the beach in the first place.
Council President Margaret Zeidman expressed interest in working with Lapointe to strengthen the town’s response to the sargassum problem, which is expected to be a recurring problem for years to come.