Theunderwater mountains, thecold water corals, the upper slopes of the continental margins and theunderwater cannonsare thedeep sea ecosystemsWhat is the greatest risk?in the short and medium term future. That is what emerges from an international study linked to the project Census of Marine Life, in which the CSIC has participated and which appears in the last issue ofPLoS ONE.
The deep sea is the area of the sea that ranges from 250 meters deep (when the continental shelf ends) to depths of between 3,000 and 6,000 meters in the abyssal areas, and thatthey can reach 11,000 meters in areas such as the Mariana Trench, in the Pacific. The deep seabed covers 73% of the ocean, an area estimated at about326 million square kilometersall over the planet. Of this extension, only an area equivalent to a few football fields has been biologically sampled.
The twenty experts participating in the new study have carried out an analysis of the most important anthropogenic impacts in the past, present and future, which affect deep sea habitats throughout the planet. They have also identified which areas of the deep sea are most at risk in the short and medium term, as well as the greatest threats to these areas in the immediate future.
At work, experts highlight other areas that in the future will have greater pressure due to thesubsea mining extraction, an activity that will begin to unfold in the medium term. It is known that there are important deposits of copper, nickel and cobalt in the magnesium nodules of the deep Pacific areas. “In addition, there is iron, cobalt, copper and platinum in the seamounts of the central and western Pacific, as well as large deposits of mineable metals (gold, zinc, copper, lead, cadmium and silver) in the massive deposits of sulphites from the sources. hydrothermal “, explains Eva Ramírez Llodra, biologist and co-author of the work.
In the past, explains the CSIC researcher, the greatest impact on the part of man was the dumping of waste and garbage into the sea, an activity that has been prohibited since 1972, but whose consequences are still present in the form oftons of garbage and plastics, in addition to uncontrolled discharges from the coast, rivers and ships. The study indicates that the main concern is the accumulation of plastics in the large seabeds, which degrade into microplastics and can be ingested by deep-sea fauna.
Currently, and due to the reduction of resources in shallow waters, the greatest pressure at the global level is exploitation, particularly fishing. In the future, however, the biggest threat is expected to beocean acidification and climate change, which act on a global level and can have important consequences from the surface to the abyssal depths.
