Oceans cover 70% of our planet and represent over 95% of the biosphere. Marine and coastal habitats cover a diverse spectrum—from those near terrestrial environments such as coral reefs, mangrove forests, seagrass beds and estuaries, to those deep below the surface, such as open ocean, hydrothermal vents, seamounts and soft sediments on the ocean floor.
More than just a valuable source of food and various economic activities, the ocean is one of the largest natural reservoirs of carbon. It stores about 15 times more CO2 than the terrestrial biosphere and soils, and plays a significant role in climate moderation.
Deep-seabed habitats host between 500,000 and 10 million species. Deep-sea life is essential to life on Earth because of its crucial role in global carbon and biogeochemical cycles, including nutrient regeneration.
This tremendous wealth of biodiversity and ecosystem services is not, however, infinite. Today, human activities are greatly threatening the seas and coasts through overfishing, destructive fishing practices, pollution and waste disposal, agricultural runoff, invasive alien species, and habitat destruction. Global climate change adds additional pressures by raising the sea level, increasing the water temperature and leading to more storms and natural disasters. Seawater is acidifying due to increasing levels of atmospheric CO2, with significant implications for marine biodiversity.
Countries that adopted the Convention on Biological Diversity are addressing various challenges to the conservation and sustainable use of marine and coastal biodiversity. By applying the ecosystem and precautionary approaches, they focus on the integrated management of marine and coastal areas, protection and enhanced management of ecologically or biologically significant areas, and sustainable fishery and mariculture management.