7 Weird Facts About Deep Ocean Vents

Field report

Prepare to be wowed by the mysterious deep-sea wonders that are hydrothermal vents.

Hydrothermal vents are perhaps the most eerily fascinating features of our ocean floor. Like smoking chimneys in a pitch-black abyss (or giant underwater furnaces), these strange structures on the seabed blast superheated water so mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure.-rich that nothing familiar can survive nearby — yet life thrives in ways that defy everything we thought we knew. What goes down into the vent, in a sense, feeds what comes out. (More on that later.)

For this reason, hydrothermal vents are invisible to casual observation, as dark as the crushing deep ocean surrounding them. Scientists know they exist not because they can see the vents easily, but because a vent's tremendous thermal plume affects the chemistry and currents of nearby seawater. Another clue is the detectable minerals and shimmering water discharged as superheated fluid meets the near-freezing ocean. In fact, these strong mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure. signatures led to the discovery of the first hydrothermal vents, along the Galápagos Rift in the Pacific Ocean, in 1977.

If all this sounds like science fiction, read on. It's only the tip of the deep-sea iceberg. As scientists are discovering, hydrothermal vents are even stranger than science fiction. Here are seven mysteries to ponder.

1. Deep Ocean Vents Twist Pressure and Chemistry Around Them

If you happened to descend near a hydrothermal vent, its extreme pressure and heat would reshape everything around you. You'd drift ever closer, gradually entering a zone of swirling mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure.-rich plume (sulfides, iron, methane, hydrogen) spiraling upward toward the vent chimney or "black smoker" — the towering mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure. column where superheated fluid erupts at temperatures exceeding 750°F (400°C). Once fluid crosses this boundary into the cold surrounding ocean, minerals precipitate instantly, building the chimney taller and coating the seafloor in metallic deposits — an inconceivably harsh environment where pressure and chemistry defy the rules of surface life as we understand them.

Take a simulated dive into the deep

2. Deep Ocean Vents Come in Modest, Medium and Monumental Sizes

Medium-sized black smokers are the most common type of hydrothermal vent. They form when cold seawater seeps into cracks in the ocean crust, gets superheated by magmaMolten rock beneath the Earth's surface. When it erupts, it is called lava. below, and rises back up laden with dissolved minerals. As the mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure.-rich fluid erupts and meets icy deep water, dark particles precipitate and build chimney-like structures. In truth, then, vents aren't really fountains, but mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure. deposit towers with outsized chemical footprints. Typical black smokers stand about as tall as a two-story house, though scientists have discovered some that soar over 180 feet high, like the towering "Godzilla" vent in the Pacific.

Lost City vents are the most colossal in the ocean, some stretching over 200 feet across their base, with carbonate spires that have grown for at least 120,000 years. Scientists don't fully understand all the conditions that create them, but these enormous seafloor monuments may have appeared early in Earth's history and are believed to exist along mid-ocean ridges throughout the world's oceans, even the most remote ones. Our own Atlantic Ocean harbors the famous Lost City hydrothermal field, perched on the Atlantis Massif seamount.

Researchers have also recently discovered low-temperature vents called diffuse flows that release shimmering warm water at gentler rates, meaning fewer visible mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure. plumes so they're harder to detect. Oceanographers also believe there are tiny micro-vents scattered across the seafloor, too small and subtle to notice. These mini-vents have yet to be fully mapped, but the smallest may be no wider than a coffee mug (but with a thriving microbial community), and the ocean floor may be riddled with them.

3. There Are Too Many Deep Ocean Vents to Count

The mid-ocean ridge system alone — the 40,000-mile underwater mountain chain that encircles the globe — is thought to harbor thousands of hydrothermal vent fields, each with multiple chimneys. With vast stretches of the deep ocean still unmapped, each ridge segment potentially hosting dozens of vent sites and a core mega-plume at its heart (not to mention new types being discovered), it's like trying to count all the hot springs on land.

4. Deep Ocean Vents Devour Seawater — and Regularly Spit Minerals Out

Rest assured, hydrothermal vents don't prowl the ocean floor like hungry predators, stalking fish and other sea creatures for dinner. Rather, these geological chimneys cycle seawater that circulates too close to the magmaMolten rock beneath the Earth's surface. When it erupts, it is called lava. below, like this unfortunate pocket of frigid bottom water that scientists have watched being drawn into the crust and chemically transformed (the longest vent-driven water cycle ever recorded). The good news is that coastal communities aren't directly threatened by any known vent activity.

But just because we're unlikely to be engulfed by a vent plume doesn't mean we shouldn't pay attention. That's because vent systems (and presumably other deep-sea features) occasionally fling out massive plume eruptions — called megaplumes — that could reshape wide areas of the deep ocean.

How do megaplumes escape a vent's chimney? They're actually caused by sudden tectonic shifts or magmaMolten rock beneath the Earth's surface. When it erupts, it is called lava. intrusions that release enormous volumes of hot, mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure.-rich fluid in a single burst. In the case of some documented megaplumes, these colossal discharges can spread across hundreds of cubic miles of ocean. Here's hoping one never erupts beneath a fragile deep-sea ecosystem we're still discovering.

5. Deep Ocean Vents Also Give Birth to New Species and Determine How Many Creatures a Reef Gets

In the same way that mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure. plumes are expelled from the vent chimney, a recent discovery shows that vent ecosystems occasionally nurture enough larvae and microbial life to seed wholenew colonieson distant sections of the seafloor. Even more remarkable, some of these colonizers drift far beyond their vent of origin, carried by deep-ocean currents.

And a 2018 study in the journal Nature Ecology suggests that hydrothermal vents not only support new species, theyshape how many species a vent community getsby directly impacting how quickly the process of ecological succession unfolds. Species diversity, perhaps strangely, develops more quickly at vents with smaller — in a manner of speaking — chimney structures at the center.

Learn more about deep-sea vent species colonization:

6. It's Possible to Peer Into the Abyss

The new deep-sea submersible fleet — powered by some of the world's most advanced remotely operated vehicles — recently captured first-time footage of thevent chimneys and surrounding ecosystems at several hydrothermal fields. One is the famous Lost City in the Atlantic and the other is a towering vent field at the bottom of the Indian Ocean, over 7,000 feet deep. The imagery from the latter,now widely circulated, astonished marine biologists in 2022, but the expedition also raised new interest in ongoing questions about what lives near vents and the mind-warping biology that thrives there.

7. Yet Another Deep-Sea Vent Head-Scratcher

Marine biologists in the Pacific recently stumbled upon a region of the deep ocean where hydrothermal vents along several ridge segments arealigned in the same orientation. That is, their mineralA naturally occurring, inorganic solid with a definite chemical composition and crystal structure. plumes all jet out as though they were synchronized by design. Current theories can't explain how vents up to hundreds of miles apart appear to be acting in concert. In fact, the only way it's possible, say researchers, is if these vents share the same deep crustal plumbing — something that may have been established during the formation of the ridge system millions of years ago.

Why the Deep Ocean Matters to Nature Lovers

The deep ocean is our planet's largest habitat and its wonders help us appreciate the hidden diversity of life on Earth. Exploring hydrothermal vents and the deep sea can also help us learn about what's happening to our climate. Deep-sea research has helped us better understand ocean chemistry, carbon cycles, and even the origins of life itself.