The Treasure Coast end of the Indian River Lagoon faces numerous visible challenges, such as Lake Okeechobee water releases into the St. Lucie River. Researchers at the University of Central Florida are now looking to see if it also has a nearly invisible big problem – extremely high levels of tiny pieces of plastic.
Mark Perry, executive director, said the Florida Oceanographic Society and other local organizations will lend helping hands to a study funded by Indian River Lagoon National Estuary Program to find out if microplastics are as pervasive as one study indicated they may be.
“I’m glad to see that people are studying it and working on it and we can expand the efforts in the southern end of the lagoon to find out if this is one of the world’s worst areas,” Perry said.
Biologist Linda Walters and others at UCF published results of microplastics research on the northern end of the 156-mile Indian River Lagoon in the peer-reviewed Marine Pollution Bulletin in 2018. The researchers found 23 pieces of plastic on average in every liter of water from the Mosquito Lagoon they sampled. They found on average 16 pieces of plastic in adult oysters from that part of the Indian River Lagoon.
In the Central Florida press, Walters has repeatedly stated that these are the highest number of microplastics found in shellfish anywhere. The high level of microplastics in oysters north of the Treasure Coast gets locals’ attention.
“It’s definitely worrisome,” Perry said. “It’s concerning us all wherever there are shellfish and shellfish restoration going on.”
The society is involved in local oyster restoration programs.
Perry said that while the slate of speakers is still getting arranged, he expects Walters will be at the upcoming Indian River Lagoon Symposium to present the recent findings and additional research on Indian River Lagoon microplastics. She’s a member of the symposium’s steering committee. The symposium will be on Feb. 7-8 at Florida Atlantic University’s Harbor Branch Oceanographic Institute at 5600 N. U.S. 1, Fort Pierce. “We’ve known about microplastics for a long time, since the ’60s,” Perry said. “Now we’re finding high concentrations in certain areas.”
The National Oceanic and Atmospheric Administration defines microplastics as any piece that’s less than 5 millimeters. There are manufactured microplastics used in products such as clothing. Then there are unintended microplastics from things such as loose fishing line breaking down over time, Perry explained in a previous St. Lucie Voice interview. “Our plastics end up in the water and break up to smaller and smaller pieces,” he said in the previous interview.
Perry explained that as plastic breaks down, smaller and smaller creatures end up eating it. Of course, the smaller the creature, generally the lower it is in the food chain. Things that eat smaller creatures ingest the plastic with them. They, in turn, get eaten by larger creatures, and the plastic – which can’t be digested – works its way to the top of food chains. He said rescuers are discovering birds that stopped eating because they couldn’t anymore.
“They’re finding their guts full of this plastic,” Perry said in that interview. “They’re full and can’t eat anything else.”
Additionally, plastic in the ocean doesn’t have to work its way into food chains to be a problem. It also acts as a binder, a material that attracts and holds others. Perry said the things that bind to plastic to stay in the ocean are never good.
“There’s a lot of unknown about microplastic,” Perry said in the recent interview. “What we seem to know is it’s really getting to be a problem. It’s showing up everywhere. It’s in marine life and maybe our tissue.”
The UCF researchers said most of the microplastic they found in oysters from the Mosquito Lagoon was apparently from ropes and possibly clothing. They’re unsure if the especially high number of microplastics is due to the estuary being a semi-closed system with limited flushing and rapid nearby development, or due to the timing of the study. What the researchers want to do next is expand the study with simultaneous samplings throughout the Indian River Lagoon from different times of the year.
Oysters are filter feeders, so are especially prone to acquiring microplastics.