For This Deep-Sea Animal, Oxygen-Free Is the Way to Be

By Andrew Moseman | April 8, 2010 10:37 am

LoriciferanMicroorganisms can live the far reaches of the planet, in extreme temperatures and pressures, and in some cases even without oxygen. But now scientists say they have found the first multicellular organisms inhabiting an anoxic environment. In other words: They’ve found the first animals living without oxygen.

They belong to the group called loriciferans, a phylum of creatures that live in marine sediment. About a millimeter long, they look something like a half-jellyfish, half-crab. The beasts live in conditions that would kill every other known animal. As well as lacking oxygen, the sediments are choked with salt and swamped with hydrogen sulphide gas [New Scientist].

Roberto Danovaro and his colleagues, who documented this find in BMC Biology, had been searching the salty, oxygen-free depths of the Mediterranean Sea down below 10,000 feet for life. When previous searches turned up animal bodies, he says, researchers wrote them off, thinking they had fallen to those depths from oxygenated waters closer to the surface. But Danovaro says his team recovered living loriciferans from the area, including ones with eggs.

Unlike plants, all previously discovered animals, and fungi, the newly discovered animal species don’t use mitochondria, the cellular organelle that converts sugar and oxygen into water, CO2 and, energy, to power their cells [Popular Science]. Instead, the animals pack the hydrogenosome organelle, a feature common among the miccoorganisms that live in oxygen-free zones.

Danovaro’s find should lead other life-hunters to start seeking animal life in locations that had been labeled inhospitable to animals, like subduction zones, hydrothermal vents, and other places only simpler organisms had been discovered. And every time we push back the preconceived limits of life on our own planet, it excites those seeking life on others. Says oceanographer Lisa Levin: “Are there metazoans on other planets with atmospheres different from our own?” Levin added. “Our ability to answer this question would be strengthened considerably by more intensive studies of animal-microbe interactions in extreme settings of our own inner space — the deep ocean” [LiveScience].

Related Content:
DISCOVER: Science Nation Video: Extremophile Hunter
DISCOVER: Looking for Life in All the Wrong Places
80beats: Tiny Invertebrates Survive a Trip Through the Vacuum of Space
80beats: Where Would Martian Life Hang Out? Under a Giant Volcano, Naturally

Image: Roberto Danovaro

  • Torah Kachur

    Once again – the power of evolution is incredible and cannot be categorized. Every time humans try to classify something we always find exceptions to the rule. What’s next – non-cellular life? Extraterrestrial life?

  • Ken Lee

    Anything is possible, sometimes our view on what’s possible is way too narrow.

  • AlexB

    amazing! now,

  • Wsa

    “There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy”

    I usually do not comment scientific blogs by quoting Shakespeare – but hey, this is a thrilling find! And by Italian scientists! It’s the first time I’m once again proud of my country since the last football World Cup!

  • Lucas

    This is amazing and also disheartening. Disheartening because so many of us believe that life cannot exist without water and oxygen. We forget though that we’re more alien than the “aliens” that we are trying to discover. It would be like a creature who breaths a harmful gas, like methane thinking it’s crazy that we breath oxygen. When really, it’s found on so many planets and moons. We’re not special because we’re the only ones living in this solar system, we’re dumb thinking that we are.

  • JJ

    I know I could probably find this out if I read more, but do they have mitochondria at all, or have they lost them completely like some of the parasitic protists?

  • Lily

    That is awesome! I can’t believe they can survive without oxygen. These are very special creatures that we should take care of and protect.

  • Vex

    Lily –

    With all due respect, how do you figure on “taking care of” and “protecting” organisms that exist 10,000 feet below the sea, in an environment not suited for any other multi-celled organism known?

    I would say that this hardy creature has already found a way to evolve and flourish in it’s environment without human interference or protection.

    I agree that this is an extremely special creature – but rather than being so eagar to “protect” it, we should marvel at this discovery and be eager to continue our search for other amazing creatures. This is an incredibly important discovery towards our understanding of just how resilient life can be!

  • Jizz Stain

    I want that millimetre thing in my coc

  • http://seaanimals cod

    which region the cod live and what is the specialty of cod


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