Scientists Discover Five Thousand New Species in the Pacific Ocean – But They Are at Risk

A selection of deep-sea specimens from the museum’s collection. Credit: Trustees of the Natural History Museum London

The Clarion-Clipperton Zone (CCZ), a massive area in the Pacific Ocean twice the size of India and rich in minerals, has been parceled out to various companies for impending deep-sea mining. To gain insights into what could be jeopardized once mining operations begin, a group of biologists has constructed the first “CCZ checklist.” This checklist encompasses all the species records amassed from past research voyages to this region.

Their research, which was recently published in the journal Current Biology, identified a total of 5,578 unique species within the CCZ. Remarkably, they estimate that between 88% and 92% of these species are completely 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.

Spanning six million square kilometers from Hawaii to Mexico, the CCZ is one of the most pristine wilderness regions in the global ocean. To study it, researchers brave the Pacific Ocean on research cruises that employ sampling techniques ranging from the technical, like remote-controlled vehicles that traverse the ocean floor, to the simple, like a sturdy box that lands on the bottom (referred to as “box core sampling”).

“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.”

By parsing through over 100,000 records of creatures found in the CCZ taken during these deep-sea expeditions, 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 are 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 of the CCZ samples. “One of my favorites is the glass sponges. They have these little spines, and under the microscope, they look like tiny chandeliers or little sculptures.”

Going forward, the team emphasizes the importance of increasing cohesive, collaborative, and multidisciplinary research efforts in the CCZ to gain a deeper grasp of the region’s biodiversity. They underline the importance of learning more about the newly discovered species and how they are connected to the environment around them. Additionally, they urge researchers to delve into the biogeography of the region to better understand, for example, why certain species cluster in particular geological regions.

“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.

Reference: “How many metazoan species live in the world’s largest mineral exploration region?” by Muriel Rabone, Joris H. Wiethase, Erik Simon-Lledó, Aidan M. Emery, Dan O.B. Jones, Thomas G. Dahlgren, Guadalupe Bribiesca-Contreras, Helena Wiklund, Tammy Horton, and Adrian G. Glover, 25 May 2023, Current Biology.
DOI: 10.1016/j.cub.2023.04.052

The study was funded by The Pew Charitable Trusts.