TAMPA, Fla. (WFLA) — A thick mat of sargassum seaweed continues to inundate beaches on Florida’s Atlantic coast, and with sea turtle nesting season in full swing, researchers warn hatchlings could get caught up in the clumps of decomposing material.
The current sargassum bloom is 5,000-miles-wide, large enough to be visible from space. While off-shore, the floating patch of seaweed provides habitat, food and refuge for marine life, including sea turtles, according to NOAA. It brings some of that marine life with it when it washes ashore, which is good news for sea birds and other critters that comb the beach for food.
While sargassum is an important part of the ecosystem, human beachgoers who encounter it are often less-than-thrilled. The seaweed produces a foul smell when it dries out and decomposes, which could affect a newly-hatched turtle’s nesting behaviors later in life, according to Kevin Johnson of the Florida Institute of Technology’s Marine Sciences Department.
“If you have a strong rotting smell overwhelming a beach when the hatchlings are born. That could affect maybe the imprinting on that beach,” Johnson told NBC affiliate WESH. Sea turtles instinctually return to the area where they hatched when it comes time to lay their own eggs.
An inundated beach could also prevent an adult turtle from returning there. Johnson said studies have shown that sargassum can stress them out and cause them to avoid entire beaches.
“Getting to their beach and laying their eggs, all that takes energy,” Johnson told WESH. “And if they have to divert for more than a few miles, they are using up energy that would go into egg laying. So that could become a stress problem affecting their reproductive potential.”
Hatchlings already have a tough time reaching the ocean between threats from predators and human activity. Some researchers believe sargassum helps shield turtles from danger, while others say it is just another obstacle for them.
“If there’s big piles of sargassum on the beach, those could provide obstacles, especially potentially a problem for the hatchlings,” Johnson told WESH. “The hatchlings are so small and so awkward I think that they could get hung up.”
The threat doesn’t go away when young turtles make it to the sea, however. Plastic trash and fishing debris can get caught up in the floating sargassum and be mistaken for food by hungry hatchlings, according to a study from the Florida Fish and Wildlife Conservation Commission.
FWC researchers found that ill or injured hatchlings were washing up along with the seaweed. After decades of study, they learned practically all of them had eaten plastic.
“Since the early 2000s, we have been examining the gut contents of wash-backs that died,” FWC researchers wrote. “The percentage that had ingested plastics was about 80% during the early 2000s, but has reached 100% during recent years.”
The FWC study found turtles captured in sargassum off-shore were in better health than the ones that washed up with the tide. Researchers said “the relationship between plastic ingestion and cause of death is often not clear,” but swallowing debris could make them less likely to seek out real food, or block their digestive tract entirely.