Aliens in the Abyss

I loved the movie “The Abyss”, despite the fact that the idea of underwater aliens seemed kind of silly at the time.

Maybe it’s not so silly…

An astounding batch of new deep-sea discoveries, from strange shark behavior to gigantic bacteria, was announced today by an international group of 2,000 scientists from 82 nations.

The Census of Marine Life is a 10-year project to determine what’s down there. Among the new findings:

A large proportion of deep sea octopus species worldwide evolved from common ancestor species that still exist in the Southern Ocean. Octopuses started migrating to new ocean basins more than 30 million years ago when, as Antarctica cooled and a large icesheet grew, nature created a “thermohaline expressway,” a northbound flow of tasty frigid water with high salt and oxygen content. Isolated in new habitat conditions, many different species evolved; some octopuses, for example, losing their defensive ink sacs – pointless at perpetually dark depths. ..

…In the eastern South Pacific, researchers found a diverse set of giant, filamentous, multi-cellular marine bacteria. They may be “living fossils” that developed in the earliest ocean when oxygen was either absent or much diminished, living on the toxic gas hydrogen sulfide, the scientists said.

methane tubeworms

methane breathing tubeworms

Deep sea explorers have found other animals that live and thrive in unearthly conditions. How do they survive?

Through chemosynthesis, it turns out. Vent species rely not on photons from the sun but on chemicals from the Earth’s interior. Tiny microbes oxidize the hydrogen sulfide that diffuses out of the vents, providing nutrients for animals higher up the food chain. Some creatures, such as the mollusks known as gastropod snails, feast on the bacteria directly; others, including predatory fish, dine on animals that have eaten or otherwise made use of the microbes; still others, like tubeworms, host the microorganisms in their tissues in exchange for organic compounds that the bacteria fashion from the vent chemicals and seawater. (The only element from above that these microbes require for their artistry is oxygen, which is abundant in seawater and was originally produced, of course, by plants. So when it comes right down to it, even these life forms ultimately rely on sunlight. Which likely made those flabbergasted biologists breathe a little easier.)

As if utter darkness were not enough, vent animals must contend with a witch’s cauldron of deadly toxicants. Foremost among them is hydrogen sulfide, one of the principal ingredients of the broiling water spewing from vents and black smokers. While vent microbes thrive on the stuff, this gas is lethal to most other organisms, including the creatures that live within wafting distance. Yet not only do those animals survive it, they depend on it as intrinsically as they do on the microbes. Hydrogen sulfide reacts spontaneously with oxygen, so as soon as vent fluids come into contact with seawater, a swift reaction occurs, releasing energy. All that energy would go to waste if it were it not for the microbes. They harness that reaction and use carbon dioxide to make organic compounds that tubeworms, for example, need to live.

If these strange lifeforms have been thriving, on earth, in these alien environments, is it such a stretch to believe that there could be all sorts of lifeforms out there that we can’t even begin to contact, or imagine, as ‘life’?

It might be a good idea to fund these underwater explorations through NASA.

About marypmadigan

Writer/photographer (profession), foreign policy wonk (hobby).
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