Deep sea surveys identify over 5,000 species in future mining hotspot

The Clarion-Clipperton Zone (CCZ) is a massive, mineral-rich region of the Pacific Ocean, spanning six million square kilometers from Hawaii to Mexico (about twice the size of India), which has already been divided up and assigned to companies for future deep-sea mining. 

To clarify how these mining operations may impact biodiversity, a team of researchers led by the Natural History Museum (NHM) in London has recently compiled all the species records from previous sea expeditions to the region, and estimated that CCZ is currently home to a total of 5,578 different species, among which 88 to 92 percent 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 study lead author Muriel Rabone, a deep-sea ecologist at NHM.

In various expeditions, scientists have employed different techniques, ranging from the use of remote-control vehicles traversing the ocean floor to that of sturdy boxes landing on the bottom of the ocean to perform “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. And it was amazing – in every single box core sample, we would see new species,” Rabone explained.

By examining over 100,000 records of creatures found in the CCZ during these deep-sea expeditions, the researchers discovered that only six of the new species found in this region – including a sea cucumber, a nematode, and a carnivorous sponge – have previously been seen in other regions. 

The most common types of animals found in the CCZ were arthropods (invertebrate creatures with segmented joints), worms, echinoderms (spiny invertebrates such as 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,” Rabone said. “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.”

In future studies, the scientists plan to increase cohesive, collaborative, and multidisciplinary research efforts to better understand CCZ’s biodiversity. Learning more about the newly discovered species and their connection to their environment could help experts better understand the risks involved in future mining operations.

“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,” Rabone concluded.

The study is published in the journal Current Biology.

More about deep sea mining

Deep-sea mining is the process of extracting mineral resources from the ocean floor. This includes seafloor massive sulphide deposits, polymetallic nodules, and cobalt-rich ferromanganese crusts. 

As these resources become harder to find and access on land, and as our technology and capability to operate at great depths improves, interest in deep-sea mining has increased.

Types of deep-sea mining:

Seafloor Massive Sulphides (SMS)

SMS are rich in copper, lead, zinc, gold, and silver. They are formed by hot springs on the seafloor near volcanically active areas, such as the famous ‘black smokers’.

Polymetallic Nodules

Also known as manganese nodules, these are rock concretions on the seafloor that contain valuable metals like nickel, copper, cobalt, and manganese. They are most commonly found in the Pacific Ocean.

Cobalt-rich Crusts

These crusts are rich in cobalt, but also contain nickel, copper, and platinum. They form on the flanks and summits of seamounts.

Environmental concerns:

Biodiversity loss

The deep sea is home to a wide array of species, many of which are not yet known to science. Mining operations could destroy or disturb these habitats and species.

Sediment plumes

When machines extract minerals from the seafloor, they generate plumes of sediment that can spread over large areas, suffocating marine life and potentially disrupting the marine food chain.

Noise and light pollution

Mining operations would introduce noise and light into the extremely quiet, dark deep-sea environment, with unknown impacts on species that live there.

Unknown long-term effects

The deep sea is the least understood ecosystem on Earth. It’s difficult to predict what the long-term impacts of mining might be, especially given that operations would likely continue for decades.

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By Andrei Ionescu, Earth.com Staff Writer

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