Discovering Deep-Sea Life's Secrets

For the first time, scientists have encountered creatures in the Clarion-Clipperton Zone of the Pacific Ocean that defy our understanding of life on Earth. Why is this significant?

The ocean is vast and open, at least until the depth of a few thousand of feet.

Discover bizarre in ocean's deepest depths
Image by Live Science

The Titanic wreck that swallowed OceanGate's Titan, the submersible built— albeit poorly— to visit the wreck, lay at a depth of 12,000 ft, teetering right above the edge of the abyssopelagic zone and this deep, light is scarce. Sinking even deeper than the abyssopelagic is the hadopelagic zone, where no light reaches at all. This is the deepest part of the ocean, as deep as the Mariana Trench goes. Many wonders of nature are born to survive here, withstanding conditions harsher than anywhere else on the surface. 

At a depth of 5000m, the pressure is approximately 500 times greater than the pressure at sea level. The deepest part of the ocean lies at 35,876 ft and is a testament to the kind of pressure that a creature born in this zone would have to withstand to be able to live here. Although little is known about the lifeforms that belong to the hadal zone, the ecology has been recorded to include wondrous cases of gigantism and inexplicable dwarfism. 

And hence, when a sea cucumber— not a new discovery but mostly a solid lifeform— is discovered as a transparent entity or something like a delicate glass sponge, a cup-shaped filter feeder, a tanaid crustacean, sea stars, corals, anemones and a striking Barbie-pink sea pig are found in this hostile environment, the individual perception of biodiversity being rare is broken. It’s surprising that, despite the severe conditions, underwater lifeforms have evolved to adapt to these habitats and are now visible en masse.

The transparent sea cucumbers, nicknamed ‘unicumber’ belong to the family Elpidiidae. 

“These sea cucumbers are some of the largest animals found on this expedition,” Dahlgren said.

It’s what makes this discovery so interesting, because it’s an open chance to learn more about life in these unexplored zones. This feat has been made possible by the expeditions led by marine ecologists, including Thomas Dahlgren of the University of Gothenburg, who brought these species to international attention. He also maintained an enthusiastic stance on the research that led to the discovery.

“These areas are the Earth’s least explored. It’s estimated that only one out of ten animal species living down here has been described by sense,” he said. 

“This is one of the very few cases where researchers can be involved in discovering new species and ecosystems in the same way as they did in the 18th century. It's very exciting.” 

These findings were facilitated by the UK National Oceanography Centre’s Seabed Mining and Resilience to EXperimental impact (SMARTEX) mission which deployed a remotely operated vehicle (ROV) to depths ranging from 3,500m to 5,500m.

To survive, these organisms apparently depend on ‘marine snow,’ or organic matter that descends from the upper layers of the ocean.