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| A dorment hypothermal vent |
ScienceDaily, January 24, 2012
Scientists at USC
have uncovered evidence that even when hydrothermal sea vents go dormant and
their blistering warmth turns to frigid cold, life goes on.
Or rather, it is
replaced.
A team led by USC
microbiologist Katrina Edwards found that the microbes that thrive on hot fluid
methane and sulfur spewed by active hydrothermal vents are supplanted, once the
vents go cold, by microbes that feed on the solid iron and sulfur that make up
the vents themselves.
The findings --
based on samples collected for Edwards by the U.S. Navy deep sea submersible
Alvin (famed for its exploration of the Titanic in 1986) -- provide a rare
example of ecological succession in microbes.
The findings were
published in an mBio article authored by Edwards, USC postdoctoral researcher
Jason Sylvan and Brandy Toner of the University of Minnesota.
Ecological
succession is the biological phenomenon whereby one form of life takes the
place of another as conditions in an area change -- a phenomenon documented in
plants and animals.
For example, after
a forest fire, different species of trees replace the older ones that stood for
decades.
Scientists long
have known that active vents provided the heat and nutrients necessary to
maintain microbes. But dormant vents -- lacking a flow of hot, nutrient-rich
water -- were thought to be devoid of life.
Hydrothermal vents
are formed on the ocean floor with the motion of tectonic plates. Where the sea
floor becomes thin, the hot magma below the surface creates a fissure that
spews geothermally heated water -- reaching temperatures of more than 400
degrees Celsius.
After a
geologically brief time of actively venting into the ocean, the same sea floor
spreading that brought them into being shuffles them away from the hotspot, and
the vents grow cold and dormant.
"Hydrothermal
vents are really ephemeral in nature," said Edwards, professor of
biological sciences at the USC Dornsife College of Letters, Arts and Sciences.
Microbial
communities on sea floor vents have been studied since the vents themselves
were discovered in the late 1970s. Until recently, little attention had been
paid to them once they stopped venting.
Sylvan said he
would like to take samples on vents of various ages to catalog exactly how the
succession from one population of microbes to the next occurs.
Edwards, who
recently returned from a two-month expedition to collect samples of microbes
deep below the ocean floor, said that the next step will be to see if the
ecological succession is mirrored in microbes that exist beneath the surface of
the rock.
"The next
thing is to go subterranean," she said.
The
research was funded by the W. M. Keck Foundation, the Gordon and Betty Moore
Foundation, the National Research Council and NASA postdoctoral fellowship
programs.
Story Source:
The above story is reprinted from materials provided by University of Southern California. The original article was written by Robert Perkins.Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Jason B. Sylvana, Brandy M. Tonerb, and Katrina J. Edwardsa. Life and Death of Deep-Sea Vents: Bacterial Diversity and Ecosystem Succession on Inactive Hydrothermal Sulfides. mBio, 2012 DOI: 10.1128/mBio.00279-11
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