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Much interest in the astrobiology community has been generated by the discovery of biological communities populating deep-ocean hydrothermal vents (i.e. "black smokers"). (1) These ecosystems rely on chemoautotrophic bacteria/archaea extremophiles as primary producers living at 40-80 C temperatures.

However, the lifetimes of these black smokers have been estimated to be of order 25 years. How are these biological communities able to migrate to newer, active vent systems in conditions of extreme cold and high pressure?

(1) Lonsdale, P., 1977, Deep Sea Research, 24, 9

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Interesting question. I don't think the pressure would be a problem unless they have an air-filled cavity equalized to a lower pressure (which I can't imagine these organisms would have) or if the dispersal required rapid movement to other depths. As far as I understand it, if you live in water and are filled with water then pressure is no big deal. –  KennyPeanuts Dec 16 '11 at 17:31
    
Yes, I am sure that the temperature would be more of a challenge. –  Poshpaws Dec 16 '11 at 17:38
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2 Answers 2

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I did some research on the topic and came accross this paper by Johnson et al. I am not a zoologist, so everything I write here is taken from the references paper.

The authors used genetics to estimate gene flow between different populations of limpets Lepetodrilus fucensis which is considered to be an endemic hydrothermal vent animal. They used a mathematical demographic model "isolation with migration" to estimate the migration of the animals across different biotopes.

The vents are distributed along the ridge segments and can be seen as small islands isolated by tens of kms from each other along the same ridge segment and thousands of kilometers between distinct ridges.

The results suggest that there is certain migration between the adjacent vent locations, that means that the flora of one vent can indeed survive the distance towards the next most proximal vent.


So, from now on is my pure speculation. Since the distance between single vents along the same ridge segment seems not be to so high we can suggest that these organisms are capable to resist the pressure and temperature on the ocean bottom while travelling from one vent to another...

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+1 Thanks for the reference. Will investigate further. –  Poshpaws Dec 23 '11 at 17:37
    
I think you mean "fauna of the vent" rather than "flora". –  Marta Cz-C Feb 2 '12 at 8:03
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Following up on Alexander's response, I read a little more on the subject by looking at some of the references in the Johnson et al. paper.

This paper discusses an interesting case where researchers could study a hydrothermal vent ecology before and after a catastrophic eruption giving a "natural clearance" experiment. Since endemic organisms were eradicated, any pioneer species must come from other vent systems.

A number of species, in the form of larvae caught in larval traps, were observed to arrive at the vent. These species, including Cyathermia naticoides, Lepetodrilus spp and Gorgoleptis spiralis, arrived at a significantly different (P < 0.05, MANOVA and ANOVA) rate to the pre-eruption larval source population rate. Larvae of one gastropod species, Ctenopelta porifera, which had been seen only once pre-eruption, arrived in significant numbers post eruption. The source of these larvae may have been from a vent 300 km away.

These authors associate this change in the populations pre- and post-eruption with the specifics of the hydrodynamic transport processes operating in the region.

A more general sequence of vent re-population is given in this article.

However, the interesting thing for me was the significant, but changing fluxes of larval species at these deep-sea vents.

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