Venturing into the ocean's depths unveils a world akin to science fiction. Encompassing seventy percent of our planet's surface, the ocean potentially harbors over two million species – most of which have yet to be discovered.
Beneath the surface, in realms devoid of sunlight, the cold, high-pressure environment unveils an astonishing diversity of ecosystems and animals, each uniquely adapted to thrive in extreme conditions.
"Animals have evolved the ability to tolerate extreme conditions,” says Lisa Levin, a researcher at Scripps Institution of Oceanography, “such as cold or hot temperatures at vents, high pressure in trenches, low oxygen in oxygen minimum zones, high hydrogen sulfide at methane seeps, and low pH at CO2 vents."
Here, we spotlight a few of the deep ocean's most intriguing residents – each of which exemplifies nature's remarkable adaptability to the extreme conditions of the ocean's depths.
1. California Sun Star (Rathbunaster californicus)
The California sun star belies its benign name with predatory prowess. Its hunting efficacy stems from its spiny exterior and dexterous tube feet, enabling it to adeptly navigate and capture prey on the muddy seafloor.
Read More: These Sea Creatures See Without Eyes — But Only Sometimes
2. Barreleye Fish (Macropinna microstoma)
That barreleye fish, which inhabit the North Pacific Ocean's twilight zone, is known for its extraordinary vision. Its transparent head houses two glowing green eyes that can rotate, allowing it to precisely locate its zooplankton prey. This deep-sea fish, measuring only about six inches long, may use its stealth and agility to steal fish trapped by jellies.
Read More: Yes, Fish Can Communicate Acoustically
3. Bloody-Belly Comb Jelly (Lampocteis cruentiventer)
The bloody-belly comb jelly has a deep crimson stomach thought to conceal its recently consumed glowing prey. Unlike true jellyfish, comb jellies glide through the water, propelled by rows of fused, hair-like cilia called combs.
Read More: Meet the Comb Jelly, the Sister Species of All Animals
4. Harp Sponge (Chondrocladia lyra)
Dwelling at depths up to 11,500 feet, the harp sponge, with its slender, ghost-like limbs extending up to two feet wide, breaks from the typical passive filter feeding of sponges and embraces a predatory way of life. Its barbed limbs are adept at ensnaring small crustaceans and fish, breaking them down inside its body.
Read More: Sponges Sneeze To Clear Out Filters
5. Giant Tubeworm (Riftia pachyptila)
At hydrothermal vents where the seafloor discharges hot, mineral-laden water, sprawling colonies of giant tubeworms thrive. These remarkable organisms, which can grow up to 6.6 feet, depend on symbiotic bacteria in their bodies to transform sulfur vent emissions into usable energy.
Read More: 10 Animals with Terrible Manners
6. Vampire Squid (Vampyroteuthis infernalis)
Named for its striking blue eyes and rusty-hued skin, the vampire squid leads a peaceful life in the ocean's depths. Contrary to its fearsome name, the vampire squid passively feeds on marine snow – drifting organic particles – using two long, sticky filaments. This modest diet supports its slow-paced lifestyle in the dark, low-oxygen waters where few predators roam.
Read More: The Eye-Popping Truth About These 4 Animals’ Enormous Peepers
7. Giant Japanese Spider Crab (Macrocheira kaempferi)
Lurking in the northwestern Pacific Ocean's depths, the Giant Japanese Spider Crab holds the title of the world's largest living crab. Its impressive carapace alone can measure up to 12 inches across, with legs that can extend up to 12 feet from claw to claw. This proficient seafloor scavenger employs its ten appendages – eight for walking and two equipped with claws – to capitalize on scraps or dead animals drifting down from above.
Read More: 5 Unusually Large Animals You Probably Haven’t Heard Of
8. Ninja Lanternshark (Etmopterus benchleyi)
The mysterious ninja lanternshark, a master of bioluminescence, dwells in the shadowy depths off Central America's coast. This shark skillfully uses counterillumination, a unique form of camouflage, to blend into the dim light of the deep sea, making it almost invisible to both predators and prey. Despite their modest size of about 18 to 20 inches, Ninja lanternsharks are adept hunters, employing their speed and light-emitting abilities to stealthily attract and capture larger prey.
Read More: What Makes These 7 Shark Species Stand Out Among the Rest?
9. Giant Phantom Jelly (Stygiomedusa gigantea)
The Giant Phantom Jelly is a benevolent behemoth of the ocean's darkest depths. Rarely seen, it boasts an impressive span of over 3 feet across its bell, with ribbon-like arms exceeding 33 feet. These remarkable arms, devoid of stinging tentacles, are adept at enveloping prey such as plankton and small fish in depths up to 22,000 feet.
Read More: Congrats, Jellyfish, the Seas Are Yours! (Now, What Are You Going to Do with Them?)
10. Bamboo Coral (family Keratoisididae)
Resembling underwater forests, bamboo corals flourish on the rocky ocean floor. These living sculptures, soaring up to 30 feet with branches full of tiny polyps, feed on plankton and other drifting organic matter. More than just ornate, these corals are dynamic animals equipped with stinging cells and bioluminescence to fend off predators like nudibranchs and sea stars. Yet, they face increasing threats from human-induced factors like deep-sea trawling and climate change, jeopardizing their slow-growing, age-old ecosystems.
Read More: There is Still Time to Save the Coral Reefs
11. Woolly Siphonophore (Apolemia lanosa)
The Woolly Siphonophore boasts a lengthy, gelatinous form up to 16 feet long. Unlike most animals that grow as a single entity, this siphonophore is a composite of thousands of cloned bodies, each specialized for different tasks. These clones work in unison, presenting a shaggy appearance and deploying a curtain of tentacles to capture a diverse range of prey, from crustaceans to small fish.
Read More: Does the Spiral Siphonophore Reign as the Longest Animal in the World?
12. Pelican Eel (Eurypharynx pelicanoides)
The Pelican Eel, named for its gaping, scoop-like mouth, is a unique deep-sea fish. Its ability to expand its throat and stomach allows it to capture sizable prey, using a balloon-like mouth as an efficient net. However, it's not an active hunter; it relies on a bioluminescent lure to attract its meals. In their reproductive phase, males grow larger olfactory organs to find mates but lose their teeth, indicating a shift of energy towards mating at the expense of other functions.
Read More: Mystery of the Vanishing Eels
A Fragile Frontier
The deep sea, along with its diverse inhabitants, plays a crucial role in maintaining the health of our planet. Yet, this mosaic of biodiversity faces growing challenges due to human activities. Deep-sea mining, climate change, and other human activities threaten these sensitive ecosystems. Protecting the deep sea is crucial for maintaining Earth's ecological balance, safeguarding vital environmental services, and preserving the extraordinary life within its depths.
Read More: Startling New Sea Creatures
