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Frontiers
Cave Dwellers' Survival Skills Are Finally Brought to Light
May 1996
A scene out of science fiction: a remote cave
in Romania, completely cut off for 5 1/2 million years from light, seasonal
change, and circulating air.
But not cut off from life.
Movile Cave, discovered in 1986, is one of Earth's most unusual ecosystems, populated
with invertebrates that have adapted -- through a process called troglomorphy
-- to their underground prison. They have done this by:
- Losing pigmentation
- Learning to navigate blind
- Surviving on bacteria and fungi that derive energy from the
sulfide hot springs beneath the cave.
The predatory leeches, rare water scorpions, and other inhabitants
of Movile Cave are similar to species found in deep sea vent communities.
They depend on chemoautotrophic organisms (users of chemical energy)
instead of the more usual photoautotrophic organisms (users of photosynthetic
energy).
"Normally, food comes to a cave from the surface," University of Cincinnati
biologist Serban Sarbu told a recent meeting of the American Association for
the Advancement of Science. "But in this case, food is being produced in the
cave using the energy that results from the oxidation of hydrogen sulfide."
This alone makes the cave unique. But there is more--33 of the 48 species found
in Movile Cave are new to science.
Some differ from their above-ground counterparts in ways that suggest Movile
Cave may be, in effect, a time capsule from ancient Romania.
When Earth's climate changed 5.5 million years ago, the area went from being
tropical to temperate. "The only animals that survived were those living in warm
caves underground," explains Thomas Kane, a biologist at the University of Cincinnati.
He points out that the cave harbors a spider whose nearest relative is in the
Canary Islands.
Until research teams began exploring Movile Cave, its 12,000 square meters were
entirely sealed off. The radioactive isotopes common in Romanian soil since the
1986 Chernobyl accident were absent from the cave's sediment. The cave's water
had a different chemical makeup than above-ground wells nearby.
Today, NSF-funded U.S. scientists and their collaborators, Romanian scientists
from the Speleological Institute in Bucharest are trying to protect the cave
while research continues. To keep the research impact to a minimum, they have
put airlocks on the entrances, wear clean coveralls and limit the number of visitors
and the length of their visits.
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