A major new survey of the seafloor has found a shocking amount of litter. This garbage, which consists of bottles, plastic bags, fishing nets, and whatever else you can think of, was found throughout the Mediterranean and reaching all the way to the Mid-Atlantic Ridge — a distance of over 2,000 miles.
Litter accumulation in our marine environments is one of the fastest growing threats for the world's ocean health. We dump over 6.4 million tonnes of litter in the oceans each year — and the effects are serious.
Aside from the ugliness of it all, litter can be mistaken for food items and be ingested by a wide variety of marine organisms. Animals can also get caught in fishing gear, a problem faced by various mammals, turtles, and birds.
Another problem is what's called "ghost fishing" — when inordinate number of fish are killed in derelict fishing gear strewn about the marine environment. What's more, floating litter facilitates the transfer of invasive species to new habitats.
The new survey was an international study involving 15 organizations across Europe and it was led by the University of the Azores. The scientists took nearly 600 samples from across the Atlantic and Arctic Oceans and in the Mediterranean Sea, from depths ranging from 35 meters to 4.5 kilometers.
"We found that plastic was the most common litter item found on the seafloor, while trash associated with fishing activities (discarded fishing lines and nets) was particularly common on seamounts, banks, mounds and ocean ridges," noted Christopher Pham from the University of the Azores in a statement. "The most dense accumulations of litter were found in deep underwater canyons."
The researchers discovered litter at each site surveyed, with plastic accounting for 41% and derelict fishing gear 34%. Glass and metal, wood, paper/cardboard, clothing, pottery, and unidentified materials were also observed. Much of the plastic originates from coastal and land sources, and are carried along continental shelves and slopes into deep water.
"The large quantity of litter reaching the deep ocean floor is a major issue worldwide," added Kerry Howell, Associate Professor at Plymouth University's Marine Institute. "Our results highlight the extent of the problem and the need for action to prevent increasing accumulation of litter in marine environments."
Read the entire study at PLoS One: "Marine Litter Distribution and Density in European Seas, from the Shelves to Deep Basins."
Images: Pham CK et al/PLOS.