Deep-sea expedition explores underwater mountains – and discovers more than 100 new species

Our oceans cover 71 percent of the Earth’s surface. Of the approximately 300 million square kilometers of seabed – about ten times the area of ​​Africa – only five percent has been explored so far. From a water depth of 200 meters it is so dark and cold, and the pressure so high, that the deep sea was long considered as hostile to life as space.

Researchers at the Schmidt Ocean Institute in California are now shedding light on this darkness. During several diving trips off the Chilean Pacific coast in January and February 2024, the team mapped more than 50,000 square kilometers of deep sea and discovered more than 100 previously unknown animal species.

Two underwater mountain ranges were examined, consisting of at least 200 mountains over a distance of 2,900 kilometers: the Nazca and the Salas-y-Gómez ridges. The mountains in particular, some of which rise more than 3,500 meters above the seabed, turned out to be surprisingly rich in species. In the vastness of the deep sea, such elevations form oases for life, as water masses from different ocean depths mix here and nutrients rise to the surface. In addition, the mountains with their rocky slopes provide a good substrate for cold-water reefs made of corals and sponges.

Equipped with a 4K camera, a remote-controlled vehicle explored the seabed at a depth of almost five kilometers below the water’s surface. In addition to recording videos and images, the robot also collected samples. The expedition’s species, which have not yet been scientifically described, include deep-sea corals, glass sponges, sea urchins and various crustaceans.

The researchers were enthusiastic. «The expedition far exceeded our expectations. People always assume that new species will be found in these remote and little-explored areas, but the amount we have found is overwhelming,” said expedition leader Javier Sellanes of the Universidad Católica del Norte. “These thriving and healthy ecosystems demonstrate that at least the Nazca-Desventuradas and Juan Fernández Marine Parks are effectively protecting sensitive marine habitats.”

However, the majority of the two ridges studied are located in international waters and are therefore potentially at risk from fishing and deep-sea mining. Bottom trawl nets, for example, mow down entire reefs that can only regenerate in the cold deep sea over the course of years or decades.

The researchers hope that the area’s diversity will help ensure it is fully designated as a marine protected area. This is intended to help preserve the unique ecosystem. “Imagine if this is the only place in the world where these kinds of species occur,” Jyotika Virmani, executive director of the Schmidt Ocean Institute, told Business Insider. “Then you also want to protect that.”