The species live in the Clarion-Clipperton Zone (CCZ), an area considered of high interest to deep-sea mining companies due to the abundant presence of manganese nodules, which contain high-value metals.
The Zone is about twice the size of India and has already been divided and assigned to companies for extraction purposes. However, the scientific community has been working to raise awareness of the biological diversity that could be lost should deep-sea mining operations take place in the area.
With this goal in mind, a team of biologists has built the first 'CCZ checklist' by compiling all the species records from previous research expeditions to the region.
The researchers found that, according to their estimates, the species diversity of the CCZ included a total of 5,578 different species found in the region, an estimated 88 to 92 per cent of which are entirely new to science.
"We share this planet with all this amazing biodiversity and we have a responsibility to understand it and protect it," said Muriel Rabone, a deep-sea ecologist at the Natural History Museum London, UK.
A selection of deep-sea specimens from the museum's collection./ Trustees of the Natural History Museum London
Image credit: Trustees of the Natural History Museum London
Spanning 6,000,000km², from Hawaii to Mexico, the CCZ has been considered one of the most biologically rich regions of the planet.
In order to better understand the CCZ, the team visited the area on research cruises and took samples with study boxes as well as remote-controlled vehicles that traverse the ocean floor.
"It's a big boat, but it feels tiny in the middle of the ocean. You could see storms rolling in; it's very dramatic," said Rabone. "And it was amazing - in every single box core sample, we would see new species."
Rabone and her co-authors found that only six of the new species found in the CCZ - which include a sea cucumber, a nematode and a carnivorous sponge - have been seen in other regions. They also found that the most common types of animals in the CCZ are arthropods (invertebrates with segmented joints), worms, echinoderms (spiny invertebrates like sea urchins) and sponges.
"There's some just remarkable species down there. Some of the sponges look like classic bath sponges and some look like vases. They're just beautiful," said Rabone. "One of my favourites is the glass sponges. They have these little spines and under the microscope they look like tiny chandeliers or little sculptures."
The team has stressed the need for more cohesive, collaborative and multidisciplinary research efforts in the CCZ to gain a deeper grasp of the region's biodiversity. They also underlined the importance of learning more about the newly discovered species and how they are connected to the environment around them.
"There are so many wonderful species in the CCZ and, with the possibility of mining looming, it's doubly important that we know more about these really understudied habitats," said Rabone.
The CCZ has already been divided into 16 mining claims spanning approximately 1,000,000km², while a further nine areas, each covering 160,000km², have been set aside for conservation.
The area is said to contain 21bn tonnes of nodules, which would include 5.95bn tonnes of manganese, 0.27bn tonnes of nickel, 0.23bn tonnes of copper and 0.05bn tonnes of cobalt.
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