Marine litter is a serious environmental problem worldwide. Reducing it would require implementing a global monitoring system, agreeing on the use of common methods and protocols for data collection, and categorizing all components of marine debris. This involves a tremendous scientific, political, and social effort at the international level - one that cannot be carried out with the same intensity by all countries - given the magnitude of what is still unknown about the pollution of seas and oceans, particularly the deep ocean, where the vast majority of marine litter accumulates.
This is one of the main conclusions of the article published in Marine Pollution Bulletin . The principal authors include Professor Miquel Canals, from the Faculty of Earth Sciences of the University of Barcelona; Georg Hanke, from the European Commission's Joint Research Centre (JRC); Ryota Nakajima, from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC); Melanie Bergmann, from the Alfred Wegener Institute (AWI) in Germany; François Galgani, from the French Research Institute for Exploitation of the Sea (IFREMER); and Daoji Li, from East China Normal University (ECNU), among other experts.
The study aims to raise awareness and emphasize the need to include marine litter - and particularly that on the seafloors - in any directive, convention, treaty, or agreement established at the national, regional, or global level to minimize marine pollution. Experts warn that the seafloor serves as the ultimate dumping ground where the vast majority of marine litter ends up.
The focus of the study is on macrolitter - items larger than 2.5 cm - that accumulate on the seafloor, the ultimate sink for marine litter. Despite its significant environmental relevance, this fraction has often been overlooked in the flood of studies on smaller-size debris, such as microplastics.
An environmental problem that begins on land
Nearly all seas and oceans are affected by marine litter, much of which reaches them via rivers. The rivers contributing the most waste are located in southern Asia (the Amur, Hai, Yellow, Yangtze, Pearl, Mekong, and the Ganges and Indus systems) and in Africa (the Niger and the Nile).
In addition to riverine inputs, certain extraordinary and catastrophic events - such as the April 2011 tsunami in eastern Japan - carry enormous amounts of debris into the ocean. Fishing and other marine activities are also continuous sources of specific types of litter, such as discarded nets, longlines, buoys, and tires used as boat fenders.
