New alien-like place found in Earth’s deep sea

Astronomy news are often about newly discovered galaxies or previously undetected planets. But there are places never seen before right here on Earth too, which may seem like extraterrestrial environments.

On Friday, a team of Irish and British scientists announced the discovery of a previously unknown system of deep-sea hydrothermal vents along the volcanic Mid-Atlantic Ridge — a boundary of tectonic plates that crosses the Atlantic Ocean. The vent field was discovered a few hundred kilometers north of the Portuguese islands of Azores, and has tall chimneys of metals and minerals that are home to alien-like lifeforms.

Researches watched vivid-orange shrimp-like creatures, that are believed to see in the infrared through a third eye which detect light through a sheet of retinal cells on their backs, crawling around the chimneys. “Elsewhere there are writhing scale-worms, swirling mats of bacteria and eel-like fish — a riot of life in this unlikely haven on the ocean floor,” stated team member Jon Copley, from the University of Southampton, in a press release. (See Jon’s comment below for more information on the strange shrimps!)

“It is too early to say whether some of them are new species or not but we are confident that at least three will prove to be,” said mission leader Andy Wheeler, from University College Cork, to the Irish Examiner.

Hydrothermal vents are cracks in the Earth’s crust from where seawater heated to boiling point by subterranean volcanic activity is spewed. This water is enriched with minerals from the molten rock, which can precipitate and eventually form roughly cylindrical chimneys resembling miniature underwater volcanos. These structures are home to an ecosystem that, in complete darkness, relies on the vent field as its primary source of energy. The rich marine life in the vents thrives on bacteria that transform chemicals in the heated water into organic material.

The vents now found are at depths of 3000 metres, and the system is the first to be explored on the Mid-Atlantic Ridge north of the Azores. The team spent 23 days on board of the Irish research vessel Celtic Explorer, and used the remotely operated vehicle Holland 1 to find the field.

Researches named the newly charted system Moytirra, meaning ‘Plain of the Pillars,’ after a battlefield in Irish mythology. “The largest chimney we have found is huge — more than ten metres tall — and we have named it ‘Balor’ after a legendary giant,” Patrick Collins from the University of Galway in Ireland said in a press release. “In comparison with other vent fields, Moytirra contains some monstrous chimneys and is in an unusual setting at the bottom of a cliff — a real beauty.”

Aside from researchers and technicians, the mission carried a TV crew from National Geographic. They filmed the discovery to include in an upcoming series called ‘Alien Deep,’ which will premiere in 2012 in the National Geographic Channel.

Moytirra3_small.jpg

Chimney of metal sulphides in the Moytirra vent field. Credit: VENTuRE Project. Source: Ryan Institute, University of Galway.
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7 thoughts on “New alien-like place found in Earth’s deep sea

  1. Jon Copley

    Glad you find this kind of discovery just as exciting as astronomy news! 😉 Given that this is a Nature network blog, I think it’s worth correcting a few errors that crept into some of the linked newspaper coverage here.
    The vent shrimp don’t really "see in the infrared through a third eye".  Their species name, "exoculata", denotes their lack of typical stalked shrimp eyes. So the unusual eye that they do have is not really a "third eye" – it’s their only functional eye.
    That "eye" is a thoracic photoreceptor – a sheet of retinal cells on their backs. It doesn’t have a lens, and so can’t form an image – it’s a "light detector", rather than an "eye" like ours.
    The shrimp don’t "see" infrared wavelengths with it either. The peak sensitivity of their visual pigment is around 500 nm, which is visual wavelength (see Van Dover et al., 1989, A novel eye in ‘eyeless’ shrimp from hydrothermal vents of the Mid-Atlantic Ridge, Nature 337: 458-460).
    So what light are the shrimp detecting around the vents? They seem to be capable of detecting light at equivalent visible wavelengths produced by the black-body radiation of hot vent fluids (see Pelli and Chamberlain, 1989, The visibility of 350C black-body radiation by the shrimp Rimicaris exoculata and man, Nature 337: 460-461). That’s not really the same as "seeing in the infrared" (in fact, if the black-body radiation from vents were just a bit "brighter", we’d be able to see their "glow" with our eyes too).
    And at vents, there also appear to be other, still-mysterious sources of light at visual wavelengths (see Van Dover et al., 1996, Light at deep-sea hydrothermal vents, Geophysical Research Letters 23: 2049-2052).

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  2. Barbara Ferreira

    Jon, thank you very much for commenting, and for pointing out the mistakes present in the news pieces I used as sources. Indeed, the "third eye" thing did raise red flags. But because there was no scientific paper announcing the discovery that I could read to fact check, I chose to believe the Irish Examiner was right. I apologise for this. I should have only trusted in the information given in the press release!
    The explanation you gave on the nature of these strange shrimps is far better (and cooler!) than anything I managed to find online, so thanks for that too. It reminds I should contact the scientists when writing blog posts, rather than simply searching for information online. If only I had more time to dedicate to this blog…

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  3. No worries, Barbara – what’s great about blogs like this is that we can chat about stories.  And the story of the vent shrimp gets even stranger…
    In a sense the unusual "eye" that they have on their backs as adults is a "third eye" if we think in terms of their life cycle.  What’s really unusual about the vent shrimp is that their larval and postlarval stages have "normal" decapod eyes, i.e. a pair of eyes, on stalks, with image-forming optics etc.
    But when they become adults, they lose those eyes, and form the "light detector" on their backs.  There’s even an intermediate juvenile stage (where the dorsal photoreceptor is not fully developed) that was originally described as a separate species ("Rimicaris aurantiaca" – Martin et al., Proc Biol Soc Wash 110: 399-411, 1997) before vent biologists figured out what was going on (Shank et al., Mol Mar Biol Biotechnol 7: 88-96, 1998).
    So why do the vent shrimp have "regular" eyes as larvae/postlarvae, and then swap them for their dorsal photoreceptor as adults?  Well, the shrimp live away from the vents in the early stages of their lives, up in the water column where they feed on ultimately photosynthetically-derived food sinking from above.  There they are subject to the same visual field and selection pressures as other mid-water deep-sea decapods (which use vision to detect bioluminescence etc).  At vents, however, gross photon sensitivity may confer a greater advantage than the visual acuity of image-forming optics (ok, I’ll admit there’s some arm-waving and a bit of a "Just-So" story in there!).
    Like most animals at vents, the adults that we see around the "black smokers", with the unusual "eye" on their backs, are just one snapshot from their life story.  The earlier stages of their lives, adapted to living in the water column away from the vents, may be crucial in allowing the shrimp to disperse between vent fields along the mid-ocean ridge.
    An individual vent field doesn’t last forever, so the species that thrive at vents all have some means of ultimately dispersing between vent fields.  In the Atlantic, because the mid-ocean ridge is "slow spreading" and less volcanically active, vent fields may be hundreds of kilometres apart.  But there appears to be surprisingly little genetic differentiation among shrimp populations over thousands of kilometres of the Mid-Atlantic Ridge, suggesting that they have a high dispersal capability (Teixeira et al., J Biogeogr 38: 564-574, 2011). 
    What I’d love to know is whether (and how) the dispersing shrimp can detect a vent field, which is typically only a few football pitches in size, somewhere in the darkness below them. Although we’re getting better at finding vent fields ourselves (this recent expedition was a prime example, thanks to the team we had on board), perhaps the vent shrimp could teach us a thing or two.

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  4. Barbara Ferreira

    Thanks again for more interesting info about these strange shrimps. They are indeed curious creatures! Let me know if you would like to write a "guest post" about them. I think it would interest the readers of Dinner Party Science (most of them probably didn’t notice your comments).

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