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Tackling microplastic pollution in Waquoit Bay

Marine Biological Laboratory team extracts core samples from Falmouth estuaries in first-of-its-kind research

STORY AND PHOTOS BY BORIS TSANG

CAPE COD TIMES SUMMER PHOTO INTERN

For most people, the mention of plastic pollution conjures up images of large garbage patches floating in the open ocean, thanks in part to the proliferation of such images on social media. The public’s preoccupation with these forms of pollution is mirrored in academia; studies in plastic pollution often focus on ocean gyres and open seas, which has led to a better understanding of the distribution of plastic debris in open marine environments.

But Javier Lloret and Rut Pedrosa-Pamies,

SEE ESTUARIES, B2

Pedrosa-Pamies, Rorty, Vandal and Lloret prepare to remove a sediment core from the marsh at Little River after driving a core liner — a tall, cylindrical tube — into the ground.

Rorty, Pedrosa-Pamies and Vandal set their sights on a marsh where they can collect samples as they enter Little River, a well-populated area on the eastern side of Waquoit Bay.

Pedrosa-Pamies assists in the extraction of a sediment core from the marsh at Little River.

MBL researchers, from left, Ruby Rorty, Rut Pedrosa-Pamies, Javier Lloret and Nicole Vandal set out from the Waquoit Bay National Estuarine Research Reserve after loading their research boat.

Vandal, Pedrosa-Pamies, Lloret and Rorty, left to right, search for a good place to take a sample after docking their boat by a marsh at Little River.

After extracting the sediment core, the team performs an extrusion, in which the sediment core is forced out of the core liner two centimeters at a time and the extruding section is sliced off and stored separately. Each section contains about six years’ worth of sediment layers that have accumulated in the marsh.

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research scientists at the Marine Biological Laboratory in Woods Hole, have their eyes set on an environment closer to home: estuaries, particularly the series of estuaries at Waquoit Bay.

“It’s a unique ecosystem in that it’s the first line between the inland and the open ocean,” Pedrosa-Pamies said. This makes the area especially prone to plastic accumulation; debris can come from both local sources inland and, due to ocean circulation, sources as distant as the Caribbean.

The scientists are specifically interested in the accumulation of microplastics, pieces of debris less than 5 millimeters in length. Although the bioaccumulation of microplastics in the food chain can affect humans, little information is available on microplastic pollution in Cape Cod estuaries. Lloret and Pedrosa-Pamies hope to be the first to quantify this pollution and its changes over different areas and time periods.

To do this, their team has been extracting sediment cores — tall, cylindrical samples — from the salt marshes around Waquoit Bay. Every day, the rising and receding tides in the bay deposit a layer of sediments, along with microplastics, on top of the marshes. These layers serve as a natural record of the history of the marshes, similar to the rings in a tree trunk. By studying the microplastics present at varying depths below the surface, the scientists can identify how the amount and type of microplastic pollution has changed in a certain location over time.

Sampling from multiple locations around Waquoit Bay will allow Lloret and Pedrosa-Pamies to also assess the impact of local populations on microplastic pollution. The basic idea is that higher population densities should correspond to higher amounts of microplastics. “It makes total sense,” Lloret said, “but nobody’s testing this kind of hypothesis,” underscoring the dearth of research on the topic. The land surrounding Waquoit Bay is notable for its wide range of population densities, making the bay an ideal place to test this hypothesis.

This summer, Lloret and Pedrosa-Pamies are joined by two undergraduate students: Ruby Rorty, a sophomore at the University of Chicago, and Nicole Vandal, a junior at Amherst College. This series of photos captures the team’s efforts as it tackles microplastic pollution in Waquoit Bay.

Rorty rearranges the containers of samples after the team returns to the Waquoit Bay National Estuarine Research Reserve.

Vandal, left, and Rorty examine processed samples under their respective microscopes at the Marine Biological Laboratory.

A processed sample from the Childs River estuary contains a turquoise plastic fragment visible to the naked eye. The remains of samples are stored in containers and organized by their locations and depths below the surface.

Rorty prepares a sample for viewing under the microscope at the Marine Biological Laboratory after removing most of the organic material.

A researcher combs through the remains of a sample under a microscope at the Marine Biological Laboratory in search of microplastics, such as microfibers and pellets. The plastics can usually be identified by their bright coloration.

After adding ferrous iron, Ruby Rorty pipettes hydrogen peroxide into a sample at the Marine Biological Laboratory to create Fenton’s reagant, a solution that destroys most of the organic material in the sample. Lithogenic materials, such as clays and rocks, are removed beforehand by submerging the sample in a saline solution, which causes the lithogenic material to sink while the organic material and microplastics float.

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