The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation.
The nonprofit organization Tara Expeditions has been active since 2003, sailing across the world's oceans to study biodiversity, the impacts of climate change and other research topics. In 2013, the schooner sailed around the Arctic Ocean to collect plastic debris floating in the water. Credit: © Anna Deniaud / Tara Expeditions Foundation.
Ocean Current Dumps Plastic in Remote Arctic Waters: The Arctic Ocean is a dead-end for plastics floating in the North Atlantic, a new study reports. The study confirms that plastics are abundant and widespread in seas east of Greenland and north of Scandinavia, even though human populations - contributors of plastic waste - are low there. The results stress the importance of properly managing plastic litter at its source, because once it enters the ocean, its destination can be unpredictable.
Historically semi-closed seas with high surrounding populations, like the Mediterranean Sea, have exhibited excess buildups of plastic debris. Such buildup has not been expected to accumulate in waters at polar latitudes, however, as they largely lack nearby pollution sources. During a 2013 Tara Oceans circumpolar expedition, Andrés Cózar et al. used nets to collect floating plastic debris, including fishing lines and a variety of plastic films, fragments and granules. Most of the ice-free surface waters in the Arctic Polar Circle were only slightly polluted with plastic debris, they report. However, plastic debris was plentiful in the Greenland and Barents Seas. Hundreds of tons of plastic fragments (with average values similar to those in areas of plastic pileup closer to the equator) were estimated from surface waters alone, and even more debris is likely on the seafloor below, the authors say. The proportion of film-type plastic in their samples supported the hypothesis that the plastic had largely traveled from distant sources, including the coasts of northwest Europe, the U.K. and the east coast of the U.S., though some could be sourced to local shipping activity.
The researchers followed the pathway of plastic in the North Atlantic Ocean using 17,000 satellite buoys, confirming the pollution flows poleward via the thermohaline circulation, a current known as the global ocean conveyer belt. Though the study concluded Arctic floating plastic currently accounts for less than 3% of the global total, this current will cause plastic to continuously accumulate as pollution from lower latitudes flows upward. The authors say the potential effects of this pollution flow on the Arctic's unique ecosystem are especially concerning.
Citation: Andrés Cózar, Elisa Martí, Carlos M. Duarte, Juan García-de-Lomas, Erik van Sebille, Thomas J. Ballatore, Victor M. Eguíluz, J. Ignacio González-Gordillo, Maria L. Pedrotti, Fidel Echevarría, Romain Troublè and Xabier Irigoien; The Arctic Ocean as a dead end for floating plastics in the North Atlantic branch of the Thermohaline Circulation; Science Advances (19 Apr 2017) Vol. 3, no. 4, e1600582; DOI: 10.1126/sciadv.1600582.