From stories of giant monsters to little green Martians, we humans can imagine some pretty strange creatures. Life, however, offers plenty of surprises here on Earth. Or should I say, under the Earth, and underwater?
If you’re talking strange creatures and alien environments, then it doesn’t get better than deepwater hydrothermal vents. As tectonic plates move apart, fissures form in the ocean floor, draining ocean water down, down, down until it reaches the roaring heat of magma. With a superheated fury, the mineral-rich water looks for an escape. Finding one, it charges up, up, up through a conduit in the crust. Rich with minerals, the water then bursts out of the vent in a superheated fury.
Sometimes these vents gape jaggedly in the seabed, open mouths belching fountains. More often they resemble great castles of Poseidon. The minerals that escape the superheated water settle around the vent, slowly building up fantastical, colorful turrets called vent chimneys.
On and alongside hydrothermal vents, lifeforms—crabs, coral, octopi—thrive. And scientists have found creatures in volcanic rock at the ocean bed around the vents. Underneath what appears to be solid ground, the bedrock contains small but labyrinthine tunnels, pits, and cavities, all carved from, or composed of now-solidified, molten lava. Diving robots have poked beneath the seafloor, finding in these hollows both temperate water and masses of creatures, including tubeworms and snails.
Previously, organisms were only thought to live on hydrothermal vents’ surfaces and fringes; belowground, the water gets warmer and warmer, toxins increase, and oxygen lessens. But these worms and snails show that life prospers where we least expect, and that truth can be stranger than fiction.
