This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The seafloor is more than just the ground beneath the sea. Two-thirds of Earth's surface is covered by oceans, which have an average depth of almost 4 kilometers (2.5 miles).
For a long time, the seafloor's remoteness protected it from widespread human disturbance. But that is changing: Bottom trawling now reaches depths of around 4,000 meters (13,100 feet) and already disturbs up to 2% of the global seafloor each year. A manganese nodule mining operation could directly affect more than 200 km² (77 square miles) of the seafloor.
Additionally, anchorage sites, shipping lanes, cables, pipelines and other infrastructure affect the global seafloor from the coast to depths of more than 6,000 meters (19,700 feet). The seafloor, however, is far more than a passive substrate. Reefs, sponge beds, mussel beds, burrowing organisms and microbial communities form habitats and regulate the exchange of carbon and nutrients between sediment and water.
"We need to understand the seafloor as an integral part of the Earth system," says Jacob Geersen, a marine geoscientist at the Leibniz Institute for Baltic Sea Research Warnemünde (IOW) and lead author of the chapter "Seafloor Integrity: Why the Bottom of the Ocean Matters," which was added to the Planetary Health Check (PHC) this year. "When we plow up sediments or fundamentally alter marine ecosystems, it is not just a matter of a local seafloor disruption. Rather, we may be interfering with processes that store carbon, recycle nutrients and stabilize entire marine food webs," Geersen explains.
In a separate chapter dedicated to seafloor integrity, this year's PHC examines these functions from an Earth system perspective, spotlighting a part of it that until now has received relatively little attention. Seafloor integrity describes the extent to which the physical structure, biotic communities and chemical functions of the seafloor are preserved. It is not yet recognized as an additional planetary boundary.
The new chapter also examines the legal and political framework for protecting the seafloor, which is based primarily on international maritime law and the importance of the precautionary principle. It highlights the challenges in implementing this framework. The far-reaching consequences of a disturbed seafloor become clear when considering its role in the carbon cycle.
Extract — continue reading at the source.
