First Ever Multicellular Animals Found In Oxygen-Free Enviro

[Steven Snyder]

From our friends at Popular Science
Linky

First Ever Multicellular Animals Found In Oxygen-Free Environment
By Stuart Fox Posted 04.06.2010 at 5:30 pm 9 Comments

In the 236 years since oxygen was identified as a life-giving necessity, no scientist anywhere has discovered a multicellular animal capable of living without the stuff. Until now. Researchers from the Polytechnic University of Marche in Ancona, Italy*, have discovered three new species that live their entire life in an anoxic pit beneath the Mediterranean Sea. This discovery drastically revises science's understand of where animals can thrive.

Prior to this discovery, the only organisms capable of life in oxygen-free environments were viruses and bacteria.

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. Instead, these weird creatures have an organelle that resembles a hydrogenosome, a cellular component used by some microbes to produce energy with complex enzymatic reactions.

The organisms themselves, none of which have been named yet, all belong to the phylum Loricifera, measure less than 0.04 inches long, and were found almost 10,000 feet down in sediment previous assumed to contain only viruses and bacteria. This is not the first time that scientists have discovered animals living in an anoxic environment, but all the previously discovered species needed to surface periodically for some O2. That makes these creatures the first animals ever discovered that spend their whole lives without oxygen.

How these animals evolved, and what else might be down in this forbidding environment remains to be seen. University of Marche scientists still have a great deal of analysis to do on these animals, but one thing is for sure: our understanding of animal life will never be the same.

* This post originally identified the researchers as working for Scripps Institution of Oceanography in La Jolla, California.

So an entirely new type of animals that don't need oxygen and don't have mitochondria? Wow...

[Samuel]

Why are they multicellular? What advantage does it give them when they can't use mitochondria?

[Steven Snyder]

Why are they multicellular? What advantage does it give them when they can't use mitochondria?

I don't know how to answer the first question, they are multicellular.

I think the reason that they do not use mitochondria is that the production of ATP in the mitochondria requires oxygen, which is unavailable to them.

...another article that goes a bit deeper.

New Scientist Linky

Zoologger: The mud creature that lives without oxygen
16:50 07 April 2010 by Andy Coghlan
For similar stories, visit the Zoologger , Mysteries of the Deep Sea and Astrobiology Topic Guides
Species name: Not yet assigned, but of the phylum Loricifera, genus Spinoloricus

Habitat: Deep sediments lacking oxygen in the L'Atalante basin of the Mediterranean Sea south of Greece – and who knows where else…

This tiny creature may not look spectacular, but it is one of the most remarkable ever discovered: the first that can survive and reproduce entirely without oxygen.

As well as proving that animals that don't have to breathe oxygen have already evolved on Earth, it bolsters claims that complex animals can evolve on other planets even if there's no oxygen. Some have speculated, for example, that sulphur-rich areas of Mars might support life.

On Earth, bacteria, viruses and ancient archaea that survive without oxygen are well-known, but they are simple, single-celled organisms. What marks out the new animal is that it has millions of cells and functions independently.

Toxic depths
Roberto Danovaro of the Polytechnic University of Marche, Ancona, Italy, led the team that discovered the creature, plus two others that live an oxygen-free existence, in sediments buried deep beneath the Mediterranean Sea. They've identified the creatures as loriciferans, tiny sediment-dwelling creatures so named from Greek because their abdomens resemble girdles.

Assigned the genus Spinoloricus, the animal is less than a millimetre long. The other two new loriciferan species Danovaro found resemble water fleas, one given the genus name Rugiloricus and the other Pliciloricus. Some specimens contained an unfertilised egg.

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.

Power supply
None of the animals has mitochondria, the "power stations" that generate energy from oxygen in the cells of all oxygen-using organisms. Instead, they rely on structures called hydrogenosomes, which generate energy from molecules other than oxygen, including hydrogen sulphide.

Hydrogenosomes are well known in protozoa and archaea that live in oxygen-free environments, but the three new creatures are the first animals to be found that rely completely on them. One possibility is that the loriciferans acquired the hydrogenosomes from archaea.

Detailed light microscopy images reveal that its abdomen "girdle" consists of eight plates connected to form a cone, tipped with a honeycomb structure of unknown function.

Lisa Levin of the Scripps Institution of Oceanography in La Jolla, California, says that the discoveries offer the tantalising promise that animal life will be found in other environments devoid of oxygen, including beyond our planet. Perhaps, she speculates, there are animals on other planets with atmospheres different from our own. More encouragement could come from further exploration of our own "inner space", the deep ocean.

Journal reference: BMC Biology, DOI: 10.1186/1741-7007-8-3

[GrandMasterTerwynn]

Why are they multicellular? What advantage does it give them when they can't use mitochondria?

They use hydrogenosomes, which are a mitochondria-like cellular organelle which produces ATP without using oxygen. What they breathe is all that hydrogen sulfide in the mud

[Solauren]

And those little critters just tossed a MASSIVE monkey-wrench into searching for extra-terrestrial life.

Free Oxygen is no longer a required component.

I mean, wow.

[Broomstick]

Why are they multicellular? What advantage does it give them when they can't use mitochondria?

Didn't you read the article? They have a different organelle that performs a similar function, but along a different chemical pathway where oxygen is not needed.

Why is anything multicellular? What advantage do YOU have in being multicelluar?

And those little critters just tossed a MASSIVE monkey-wrench into searching for extra-terrestrial life.

Free Oxygen is no longer a required component.

I mean, wow.

Yes, wow.

This makes it more likely that we are not alone in the universe.

[Samuel]

Didn't you read the article? They have a different organelle that performs a similar function, but along a different chemical pathway where oxygen is not needed.

Why is anything multicellular? What advantage do YOU have in being multicelluar?

I didn't realize it was equivalent to mitochondria- especially since

Hydrogenosomes are well known in protozoa and archaea that live in oxygen-free environments,

which implies that you can have them in bacteria.

[Admiral Valdemar]

...which implies that you can have them in bacteria.

You can have all sorts of organelles in other species that may/may not utilise them. Most bacteria won't need the same metabolic pathways that extremophiles use, for instance.

This is an amazing discovery. The idea that we can have such complex life in a totally hostile environment to what we'd expect on Earth, is a great prospect for finding life elsewhere, as Broomie mentions. There may be organisms out there that aren't merely unicellular and fairly basic in ecology, it could lead to much more, though the limits to this kind of metabolism may be different.

[Temujin]

And those little critters just tossed a MASSIVE monkey-wrench into searching for extra-terrestrial life.

Free Oxygen is no longer a required component.

I mean, wow.

Yeah, this is just awesome!

I was just thinking about the Drake equation the other day and running some numbers on a Drake calculator. This certainly will support the case for using a more liberal outlook on just where life can arise and thrive, not to mention evolve into more complex forms.

[Ilya Muromets]

And those little critters just tossed a MASSIVE monkey-wrench into searching for extra-terrestrial life.

Free Oxygen is no longer a required component.

I mean, wow.

Well, there were all those speculation about possible non-oxygen-guzzling lifeforms. But now there's actual proof!

Science, fuck yeah!

[Sarevok]

Impressive find. But I would not raise hope for any sentient life arising on planets with no oxygen content. If I am not mistaken anaerobic respiration is very inefficient so large and complex thinking creatures are unlikely to survive without breathing at least some oxygen.

[Knife]

Impressive find. But I would not raise hope for any sentient life arising on planets with no oxygen content. If I am not mistaken anaerobic respiration is very inefficient so large and complex thinking creatures are unlikely to survive without breathing at least some oxygen.

Indeed, Kreb cycle. IIRC, 36 ATP's as opposed to 2 ATP's in anaerobic production.

Edit: fact checking myself, it is actually 30 ATP's per glucose molecule going through the cycle.

[Ilya Muromets]

Impressive find. But I would not raise hope for any sentient life arising on planets with no oxygen content. If I am not mistaken anaerobic respiration is very inefficient so large and complex thinking creatures are unlikely to survive without breathing at least some oxygen.

I'm not so much excited for implications of sentient life rather than for just any sort of extraterrestrial life in general.

At this point, I'd be happy with solid proof for non-Earthly microbes. Even that is gonna have big implications for science as we know it.

[Duckie]

Sadly, this type of life would be harder to spot in the cosmos though. Why? Well, if we detect a planet, we can easily spectroscopy it, and if it has an usual amount of oxygen in its atmosphere in addition to organic compounds and is in a habitable zone, that's an unavoidable hallmark of either a new stellar process we don't know about or earthlike life, with emphasis on the latter.

If we discovered an exoplanet with this sort of life on it, we'd sadly not be able to tell short of sending a probe to it and landing on the damn thing to scoop samples. Which is obviously far less convenient and probably never going to happen outside of our solar system.

[Surlethe]

Whoah, guys, of course free oxygen isn't necessary for life. Life on the Earth started without free oxygen. The implications about extraterrestrial life are what Duckie said: there may be some planets where this kind of life dominates, and we wouldn't be able -- at this point -- to detect it via spectroscopy.

[Serafina]

Whoah, guys, of course free oxygen isn't necessary for life. Life on the Earth started without free oxygen. The implications about extraterrestrial life are what Duckie said: there may be some planets where this kind of life dominates, and we wouldn't be able -- at this point -- to detect it via spectroscopy.

Actually, i think the news about this is that it is multicellular life without free oxygen.
As far as i know, that was mostly considered too impractical to evolve before that.

[wautd]

Wow, fascinating news. This surely adds to the probability of extraterrestrial life in the universe.

[Admiral Valdemar]

Whoah, guys, of course free oxygen isn't necessary for life. Life on the Earth started without free oxygen. The implications about extraterrestrial life are what Duckie said: there may be some planets where this kind of life dominates, and we wouldn't be able -- at this point -- to detect it via spectroscopy.

Serafina got this. There's nothing unique about the metabolic pathways utilised by this organism, it's simply the scale of complexity which warrants awe. It'd be like running a marathon without breathing, whereas before all you got was to the end of your drive.

[Bedlam]

I wonder what direction this came to its current form from.

Was it an multi cellular organism which lost its mitochondira after living in an anoxic enviroment or was it a unicellular organism which in a form of parallel evolution developed a multi-cellular structure.

I'm not sure which would be most likely, the first probably requires the least number of steps to acheive.

I also wonder if its constantly multi-cellular or if like some bacterial communities it groups up under certain conditions, how specalised are its verious cells, does it have anything like organs even if they only consist of a few specalised cells.

[Broomstick]

Obviously, more research is needed.

[Vehrec]

I wonder what direction this came to its current form from.

Was it an multi cellular organism which lost its mitochondira after living in an anoxic enviroment or was it a unicellular organism which in a form of parallel evolution developed a multi-cellular structure.

I'm not sure which would be most likely, the first probably requires the least number of steps to acheive.

I also wonder if its constantly multi-cellular or if like some bacterial communities it groups up under certain conditions, how specalised are its verious cells, does it have anything like organs even if they only consist of a few specalised cells.

Best way to tell would be genotyping, but given that they belong to a known Phylum, I'm guessing the former rather than the later.

[Gil Hamilton]

Sadly, this type of life would be harder to spot in the cosmos though. Why? Well, if we detect a planet, we can easily spectroscopy it, and if it has an usual amount of oxygen in its atmosphere in addition to organic compounds and is in a habitable zone, that's an unavoidable hallmark of either a new stellar process we don't know about or earthlike life, with emphasis on the latter.

Actually, we cannot spectroscopy it, at least not unless we get much closer. All extrasolar planets are detected by seeing how it affects its primary, not by visualizing the planet itself. We certainly do radio astronomy to do rotational spectroscopy, but its on massive gas clouds, not planets. We can only do emission spectroscopy on stars because they are enormous radiators; planets are not, as a general rule, unless they start blasting out radio waves... and that is a better indication that something is alive down there than spectroscopy for obvious reasons.