A recent joint study conducted by researchers at the University of South Florida St. Petersburg and Eckerd College found over four billion plankton-sized particles of plastic floating in the waters of Tampa Bay.

Less than an eighth of an inch in size, these microplastics are often undetectable to the human eye. Despite their miniscule size, these plastic particles can wreak havoc on the marine environment as fish, bivalves and other marine creatures confuse them for food.

“We know plastics are already full of toxic chemicals, and then we know that there are a lot of chemicals that are long lasting and persistent in our environment,” said Kinsley McEachern, the study’s lead author and recent graduate of USF St. Petersburg’s environmental science and policy master’s program. “When plastics are transferred into the environment, they absorb a lot of these chemicals onto them - almost like the way oil sticks to a pan when you’re cooking.”

Ingestion of these plastic particles can cause blockages in the intestines of marine life, and, since the chemicals attached can mimic hormones, cause changes on a cellular level that leave them unable to reproduce.

McEachern says that the chemicals found in these plastics can mimic human reproductive hormones and have been linked to reproductive issues and an increased risk of cancer.

Trolling for Data

Using funding from the Tampa Bay Estuary Program and boats provided by the Hillsborough County Environmental Protection Commission, the team of researchers tracked 24 stations across the bay - including both industrial areas and more pristine mangrove habitats - over a 14 month period.

The team collected data by lowering a device into the water to get single, direct samples of a particular spot, and by towing a plankton net behind the boat, which enabled them to distill thousands of liters of water over a distance into a single testable liter. The team also collected sediment samples.

After testing the samples in the lab, the researchers found an average of four plastic particles per gallon of water collected and over 600 pieces of plastic per pound of sediment.

Plankton tow nets allowed the researchers to filter thousands of liters of open water into a single testable liter. KINSLEY McEACHERN

Mostly fibrous, thread-like plastics appeared in the water samples, while denser plastic particles were found mostly in the sediments.

McEachern said that foam particles were noticeably absent from the findings, likely due to all the samples being collected below the water’s surface.

“Comparatively, our numbers were higher than what [other resaerchers] found in the open ocean, but compared to other industrialized bay ecosystems, we found similar concentrations,” said McEachern.

But McEachern noted that the numbers found in the study are a conservative estimate.

“This is just a preliminary study,” said McEachern. “It allows us to have a baseline and really develop the type of sampling and analytical techniques that we can use to capture and identify microplastics.”

Thanks to a three-year grant, researchers at Eckerd College will continue to collect water samples and update the findings.

“[The study] was the first of it’s kind looking at microplastics in Tampa Bay over space and over time,” said McEachern. “It allows us to really look at the numbers now and then see if management and legislation change, like banning straws or banning bags, are really working.”

Here to Stay

Plastic waste, like the water bottles and grocery bags that wind up in the bay, can take over 450 years to fully decompose. Even with factors like wave action and the sun’s UV light helping to break down larger objects into tiny particles, it can take multiple lifetimes to disappear completely.

“Once they’re there, they are there to stay,” said McEachern. “It’s really hard to quantify how long plastics do persist in the environment, but we do know that all the plastics that’s been in production and disposed of in our marine environments will be effecting us for years to come.”

Though research is being done to figure out how to remove microplastics from marine environments, McEachern says that the best way to reduce the amount of plastics in the water is to cut the pollution off at the source.

“If you had a bathtub running with water, you wouldn’t keep taking buckets out. You would turn off the tap,” said McEachern.

She says the biggest way that people can help stop the spread of microplastics is by making the switch from single-use plastics to reusable options.

“Vote with your dollar. Support restaurants and businesses that making sustainable products or using alternatives to plastic packaging," said McEachern. "And really think about your own use when you’re using them, because the minutes- or even seconds- that you’re using them have consequences for ecosystems that last a lifetime.”