Sailing on a Plastic Sea

By MEREDITH HAAS/ecoRI News contributor

NARRAGANSETT — The majestic, 134-foot brigantine-rigged sailing school vessel Corwith Cramer reminds us of a time when our lives were free of petroleum and its byproducts; an age when men traversed the 72 percent of the earth’s surface that is covered by the sea without fossil fuels, under just the power of the wind.

We have only just skimmed the surface in our understanding of the blue environment, but what has been found on the surface by the Sea Education Association (SEA) North Atlantic Expedition, more specifically on the starboard side of the Corwith Cramer, is surprising and demands a deeper inspection of just how our daily lives impact the environment.

Today, the Corwith Cramer sails not only on the great expanse of blue as early explorers did, but also on 1,100 metric tons of plastic and trash, according a study by the SEA, a nonprofit dedicated to educational deep sea research.

In a Metcalf Institute sponsored presentation at the Coastal Institute last week, Kara Lavender Law, Ph.D., confirmed that anywhere from 60 percent to 80 percent of the trash collected in the ocean is plastic and it is persistent in the environment.

It is buoyant, hard to break down and easily disposable because it’s cheap to make. This is a problem, said the research oceanographer with Sea Education Association. Although the common misconception is the appearance of floating landfills visible floating landfills, “It may not be a landfill but it’s still 1,100 metric tons of trash that didn’t exist before," assures Law. And that’s only at the surface, never mind what has yet to be found throughout the water column and the ocean floor. 

Law has been part of a two-decade-long study that has produced the longest and most extensive record of plastic marine debris in any ocean basin. Students and researchers aboard the SEA’s expeditions have collected marine debris using fine-mesh nets towed alongside the research vessel, collecting more than 64,000 plastic pieces in the western North Atlantic Ocean and the Caribbean Sea between 1986 and 2008.

“It’s a plastic soup,” said Sky Morét-Ferguson, an assistant researcher for SEA, in a presentation in early November of last year, explaining that most of trash found on a 2010 expedition was bits of plastic between 2 and 6 millimeters, the size of a staple. “It’s not visible to the naked eye. ... It’s heartbreaking.”

The environmental impacts of plastic marine debris are wide-ranging and include entanglement of and ingestion by marine wildlife, transportation of invasive species, and toxicity upon ingestion and/or breakdown in the water.

Derelict fishing gear entangles divers and swimmers; traps, wounds or kills, fish, shellfish, birds and marine mammals. It also degrades habitats, and damages the propellers and rudders of recreational boats and commercial and military vessels.

Many organisms ranging from marine mammals to seabirds to plankton ingest plastic debris that interferes with metabolism or acts as a toxin with unknown impacts.

“We found 47 pieces of plastic in the stomach of a trigger fish,” said Law, noting she has seen the same thing in seabirds.

Plastics can also act like rafts that remove species from their natural environment or transport other species, such as bacteria, and can become sponges for compounds such as DDT, PCBs, PAHs and BPA, which can have harmful effects on human and marine life. How this impacts a species when ingested, how it is transported up the food chain and how that may impact food supply is still unclear.

Other unknowns, according to Law, are the chemical impacts of plastic degradation in the ocean by UV radiation or microbes and the sources and lifespan of plastics in the ocean.

“We don’t know how much plastic is entering the ocean or where the sources are,” she said, explaining that more research is underway looking at the densities of plastics collected to know what exactly the plastic source is. Different manufactured plastics can vary in density and have different chemical makeups. For example, Nylon contains nitrogen while other plastics are limited to carbon and hydrogen, or oxygen.

Where does it come from, where does it go?

Chemical analysis of plastic collected show that all known post-consumer plastics can be found on beaches. Other sources of marine debris include, river and sewage runoff, winds from storms and ships or at-sea platforms, according to Law.

“All drains lead to the ocean,” she said.

Although ocean-based sources have decreased since the introduction of an international protocol to limit pollution and dumping into the ocean in 1978, the global production of plastic materials increases 9 percent every year in concert with an increased discard rate of plastic material in the United States, according to an August 2010 report in Science.

Where the plastic comes from is still an area with much-needed attention, but where does it go?

Research from the aforementioned study showed that lower concentrations of plastic where found near land and higher concentrations were further out at sea. The highest concentrations seemed to be associated with convergence zones in which ocean currents and surface winds converge, forming gyres. There are currently five accumulation zones, according to Law: the North and South Atlantic Ocean; the North and South Pacific Ocean; and the Indian Ocean.

The goal of the Plastics at Sea Expedition last summer was to identify the eastern extent of the accumulation zone in the North Atlantic between the latitudes 22°N and 38°N. Law said they were finding higher concentrations the further east they went before having to turn around.

Can we clean it up?

Since there is no real “garbage patch,” cleaning up marine debris would be timely, costly and not necessarily beneficial, Law said.

“It’s not possible for small debris, which is the most abundant,” she said, explaining that if we were to sift through all those pinky-sized plastic pieces we could be removing plankton and other organisms beneficial to the environment. “It might be possible for derelict fishing gear, however.”

The best solution she said is to prevent plastic from entering the ocean in the first place, reinforcing the old adage, “Reduce, Reuse and Recycle.”