GOTHENBURG, Sweden — The deep abyssal plains of the Pacific Ocean, largely unexplored by humans, are teeming with bizarre life forms perfectly adapted to the harsh conditions of this alien environment. A recent 45-day research voyage to the Clarion Clipperton Zone between Mexico and Hawaii has revealed a fascinating glimpse into this undersea wonderland.
“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 science,” says Thomas Dahlgren, a marine ecologist at the University of Gothenburg who was part of the expedition, in a media release.
The abyssal plains they studied lie a staggering 3,500 to 5,500 meters (2-3 miles) beneath the ocean surface, stretching out in a vast underwater desert that covers over half the planet. Despite the inhospitable depths and lack of sunlight, Dahlgren says there is an astonishingly rich diversity of life.
“This is one of 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,” Dahlgren explains.
What did scientists find?
Using a remotely operated vehicle (ROV) to explore and photograph the deep, the scientists encountered translucent sea cucumbers, delicate glass sponges, and bizarre “sea pigs” – stubby pink sea cucumbers with protruding tubular feet used to ingest nutrient-rich sediments.
“These sea cucumbers were some of the largest animals found on this expedition. They act as ocean floor vacuum cleaners, and specialize in finding sediment that has passed through the least number of stomachs,” explains Dahlgren.
In this nutrient-starved realm, animals must make the most of the meager “marine snow” – a slow drift of organic particles from surface waters. Most deep residents are specialized filter feeders like sponges or sediment feeders like sea cucumbers.
One of the most extraordinary finds was a bowl-shaped glass sponge from a genus believed to include some of the longest-lived creatures on the planet.
“They can live up to 15,000 years,” marvels Dahlgren.
The astounding lifespan allows the sponges to grow enormous in size over millennia, sustained by the marine snow that is their sole food source settling down here at a glacial pace. Just as remarkably, they are able to accomplish this at crushing pressures over 500 times greater than at the surface.
“The lack of food causes individuals to live far apart, but the species richness in the area is surprisingly high. We see many exciting specialized adaptations among the animals in these areas,” says Dahlgren.
Scientists warn human activity could destroy this life
However, these fascinating ecosystems face an existential threat from the prospect of deep-sea mining for valuable metals used in green technologies like solar panels and batteries. Several nations and corporations are poised to extract these mineral resources once permits are approved.
“We need to know more about this environment to be able to protect the species living here,” cautions Dahlgren. “Today, 30% of these marine areas in consideration are protected, and we need to know whether this is enough to ensure that these species aren’t at risk of extinction.”
The researchers aim to catalog the bizarre residents of the abyssal plains and understand how their intricate ecosystem might be impacted by the industrial mining operations looming over this largely unexplored alien world.
StudyFinds Editor Chris Melore contributed to this report.