Marine pollution has been a focus of SEA Semester student research since the early 1980s. Tar balls and plastic particles have been collected and counted in routine, twice-daily surface plankton net tows, resulting in long-term records of contamination in the North Atlantic Ocean, Caribbean Sea, and North and South Pacific Oceans. During this time, the occurrence of floating tar balls has substantially declined, in contrast to floating plastic debris, which continues to persist. Ocean plastics are the focus of multiple avenues of research by SEA faculty and SEA Semester students to better understand their sources, distribution, transport, and fate in the ocean.
Moving beyond scientific study, SEA is dedicated to communicating environmental issues and sustainability strategies to broad audiences as well as inspiring community members of all ages to actions supporting marine conservation. Through policy classes, many semesters of SEA students contributed to the Trash Shouldn’t Splash toolkit development, which aims to reduce single-use (disposable) plastics.
SEA has conducted two research expeditions, crewed by volunteer SEA alumni, dedicated to the study of plastic marine debris. For each expedition a website documented the daily activities onboard the ship, sharing the scientific findings and teaching readers about the subject of marine debris:
Plastics at SEA: North Atlantic Expedition 2010
Plastics at SEA: North Pacific Expedition 2012
Microplastic abundance and distribution
Most plastic debris collected in our surface-towing plankton nets can be classified as microplastics (smaller than 5 mm in size), whether easily-identifiable industrial resin pellets, the “raw material” of plastic products, or particles derived from the breakdown of larger items. Microplastic measurements from more than 12,000 plankton net tows have been used to map the distribution of this floating contaminant, which is transported by large-scale ocean currents into accumulation zones in the subtropical gyres of the North Atlantic, North Pacific, and other basins. SEA’s decades-long time series also allow for investigation into potential increases in floating plastic abundance in response to increased plastic input into the ocean over time.
SEA faculty and collaborators: Kara Lavender Law (SEA), Jessica Donohue (SEA), Christopher Reddy (WHOI), Giora Proskurowski (MarqMetrix), Nikolai Maximenko (University of Hawaii)
Selected Microplastic abundance and distribution papers and publications
Ingestion of marine debris has been documented in more than 300 species of marine animals ranging from invertebrates to fish and from seabirds to marine mammals. The impacts of microplastic ingestion are an area of active research – there is concern not only about the effects on individual animals, but also the possibility that microplastics, or the chemical contaminants associated with them, might be passed up the food web. Past SEA experiments considered selective grazing of microplastics with and without chemical contaminants by a common species of zooplankton near the base of the food web.
SEA faculty and collaborators: Kara Lavender Law (SEA), Anthony Andrady (North Carolina State University/Helix Science), Amy Siuda (Eckerd College)
Selected Microplastic ingestion papers and publications
Plastic degradation in seawater
Plastics are synthetic polymers designed for strength and durability. As such, they are very resistant to degradation in the environment. Weakened by exposure to ultraviolet radiation, plastics fragment into smaller and smaller pieces. How small these pieces become, and how long they remain plastics before being fully degraded by microbial action, are open questions. Using the decades-long archives of floating debris collected by SEA Semester students in the Atlantic and Pacific Oceans, SEA researchers investigate the physical and chemical signatures of degradation, with complementary laboratory and field exposure experiments designed to determine the time scales of these weathering signatures.
SEA faculty and collaborators: Kara Lavender Law (SEA), Jessica Donohue (SEA), Giora Proskurowski (MarqMetrix), Anthony Andrady (North Carolina State University/Helix Science)
Floating tar balls result from weathering of both naturally occurring and maritime industry-sourced oil slicks. Coincident with implementation of international regulations to ban oil discharge from ships, surface plankton net tow sampling conducted by SEA in the Sargasso Sea documents a decline in frequency of tar balls from 1977 to 2012. Today, it is quite rare to encounter tar in our nets. The chemical composition of SEA’s archived tar samples has been examined to identify geographic patterns in source oil type.
SEA faculty and collaborators: Andrew Peters (Bermuda Institute of Ocean Sciences), Christopher Reddy (WHOI)
Selected Tar pollution papers and publications
The “Plastisphere”: Microbial communities on plastic debris
Plastic debris is rapidly colonized by diverse microbial communities referred to as the “Plastisphere,” which are distinct from microbial communities in surrounding seawater. This relatively new, anthropogenic substrate develops a biofilm of microbes including phototrophs, heterotrophs, potential pathogens, predators and symbionts that may influence marine food webs and biogeochemical cycling. Past SEA investigations into Plastisphere community structure and function on plastic fragments included the help of SEA Semester students.
Selected The "Plastisphere": Microbial Communities on Plastic Debris papers and publications
Vertical mixing of floating microplastics
Microplastics at the sea surface float because they are less dense than seawater, but energy from the wind creates turbulence that can mix these buoyant pieces tens of meters deep, out of reach of surface plankton nets used to collect them. SEA scientists assess the physical properties of marine debris and use an experimental setup to measure how fast particles rise back to the surface. Together with the physics of ocean turbulence, this data informs models that predict how much plastic is mixed below the sea surface under different wind and weather conditions.
SEA faculty and collaborators: Kara Lavender Law (SEA), Jessica Donohue (SEA), Giora Proskurowski (MarqMetrix), Tobias Kukulka (University of Delaware)
Video courtesy of Tobias Kukulka
Selected Vertical mixing of floating microplastics papers and publications
Out on the Reef
May 10, 2018
Carly Carter, A Watch, Longwood University
Yet another beautiful day in Bermuda! Today we got to go to the Aquarium and learn more about Bermuda’s unique marine ecosystem! They had a few radical exhibits, including one about the Sargasso Sea! Alex, Kendra, and I geeked out at the hydroid section of the poster because that is what our experiments are on- check out that Clytia species (surprisingly not noloformis) and that Aglaophenia latecarinata!
Plastics in Our Oceans: We’re All in the Same Boat
November 27, 2017
S-276 Conservation & Management Class
Hello, dear reader!
Up until now, daily blog posts have covered life onboard our floating home/lab and the cultural research, science deployments, and sail handling—with the occasional relay race or poetic interlude thrown in to boot—that comprise our day-to-day on the Seamans. Today, however, S-276’s Conservation & Management class have the privilege of sharing some of the research we’ve been conducting in both Woods Hole and here in New Zealand (well, several hundred miles offshore, currently).
Beach Cleanup & Seaweed Snacks
July 12, 2017
Ava Kiss and Lauren Adamczyk, Pierson High School and Dover-Sherborn High School
After a lovely cereal breakfast, we headed over to the Madden Center for Oceans & Society class with Kate. Today we learned about container ships and their effect on the oceans and the economy. Next was Oceanography class with Jess where we talked about the many major issues that face our oceans as well as possible solutions.
8 Things You Can Do for World Oceans Day!
June 08, 2017
Jessica Donohue, SEA Research Assistant
This World Oceans Day, the focus is on encouraging solutions to plastic pollution, and preventing marine litter.
At SEA, we’ve been studying plastic pollution for a long time. The plastic we study is collected in our neuston nets floating at the surface of the open ocean. Mostly, we find microplastics (pieces less than 5mm in diameter, usually broken down from larger objects).
It’s a serious problem, impacting marine life and degrading marine environments.
Science, Policy, & Trash…Oh my!
May 11, 2017
Paige Petit, Starboard Watch, College of the Holy Cross
Although we have only been here for about 5 days now, our routine morning stroll to the courtyard in St. George’s already feels instinctive to me. This morning we started off with a special treat from our amazing steward, Sabrina, …homemade bagels! She never fails to keep us full and happy, which is definitely a priority when your daily schedules are as packed as ours are.