Litter on the Sea Floor Along European Coasts

The distribution and abundance of large marine debris were investigated on continental shelves and slopes along European Seas, including the Baltic Sea, the North Sea, the Celtic Sea, the Bay of Biscay and different areas in the north-western basin of the Mediterranean Sea and the Adriatic Sea. On the basis of 27 oceanographic cruises undertaken between November 1992 and August 1998, different types of debris were enumerated, particularly pieces of plastic, plastic and glass bottles, metallic objects, glass, and diverse materials including fishing gear. The results showed considerable geographical variation in concentrations, which ranged from 0 to 101 000 pieces of debris per km 2. In most stations sampled, plastic (mainly bags and bottles) accounted for a very high percentage (more than 70%) of total number of debris, and accumulation of specific debris, such as fishing gear, was also common. In some areas, only small amounts of debris were collected on the continental shelf, mostly in canyons descending from the continental slope and in the bathyal plain where high amounts were found down to more than 500 m. Dives using the manned submersibles Cyana and Nautile between 50 and 2700 m allowed accumulation areas to be detected on the sea floor. Analysis of these results revealed the influence of geomorphologic factors, local anthropic activities and river inputs. Temporal trends indicated a stable situation in the Gulf of Lion and seasonal variations in the northern part of the Bay of Biscay. Accumulation areas were detected 200 km west of Denmark, in the southern part of the Celtic Sea and along the south-east coast of France.