A sealed ecosystem deep below ground
By Matthew Kalman, Globe Correspondent | June 1, 2006
JERUSALEM -- A chance discovery by a teenage spelunker has revealed the existence of eight new animal species in an underground cave in Israel, including the first terrestrial animal with no known relative found only in a cave , scientists announced yesterday.
The new life-forms were discovered in a huge limestone cavern more than 300 feet below ground that experts said had probably been undisturbed for millions of years.
Scientists at the Hebrew University in Jerusalem said at a press conference four aquatic species and four terrestrial species were found in the cave and that they were probably unique to the undisturbed ecosystem. Seven of the species were thought to be related to other known species, they said.
Matan Avital, 18, from Beit Horon, a West Bank settlement near Jerusalem, stumbled across the animals earlier this month as a member of a small team of volunteer spelunkers exploring a newly discovered network of natural underground tunnels exposed near a cement quarry alongside the main Jerusalem-Tel Aviv highway.
``I went down to check out an underground lake we found in this huge cavern when I noticed there were tiny animals swimming around in the water," Avital said in an interview. Avital said he called to Israel Naaman, a master's student in geography at Hebrew University who was directing the cave exploration. Naaman caught the swimming creature in a plastic container.
``It was very difficult to catch it because it was swimming so fast," Avital said. ``It took us five or six minutes to catch this little thing. . . . We had no idea what it was. Israel took it to the experts. The more they examined it they realized it was something out of the ordinary, a new discovery," Avital said.
Joel Despain, a cave management specialist for Sequoia and Kings Canyon National Parks, who helped discover 27 new species in a network of California caves earlier this year, called the discovery ``a big deal."
``It's definitely quite significant," he said in a telephone interview when told of the Israeli scientists' discovery. ``It could have important ramifications for taxonomy, the science of classifying animals and plants. Biologists are constantly revising the family trees. Finding something very new and unique will have an impact on how things are classified in that branch of the tree."
Avital, who said he has ``always loved exploring since I was a small boy," is volunteering at the cave research unit in the Geography Department of Hebrew University during a year off between high school and service in the Israeli Army. He said some of the underground tunnels were barely large enough to crawl through, while others had perilous drops which could only be negotiated using climbing gear.
Avital's find led university scientists to explore the 1.5-mile-long underground network where they discovered the eight species in and around the underground lake.
The largest of the aquatic animals is an albino crustacean about two inches long with a cigar-shaped body, six legs, and two pincer-like claws.
The creature appears to be related to a species found in only three other places -- southern Italy, the coast of Libya, and the northern corner of the nearby Sea of Galilee.
But tests show the newly discovered animal has a different DNA and a different physical structure.
Like all the species discovered in the cave, it has no eyes.
Two of the aquatic crustaceans found in the brackish lake were saltwater species, while the other two were freshwater, suggesting they arrived in the cave from different sources at different times. All but one of the life forms -- a tiny scorpion -- were found alive. The scientists said they were confident further exploration would yield live examples of this creature as well.
The scientists said yesterday the animals have been sent to specialists around the world for laboratory testing. The animals have not yet been named.
The sealed cavern, dubbed the Ayalon Cave by the scientists, lies 300 feet below ground level and is impermeable to rainwater because of a thick layer of chalk above the roof. It appears to have been isolated from the outside world for millions of years, creating a unique ecosystem.
``Normally, chalk is slightly porous, but a layer tens of meters thick as this was would not have allowed surface water to penetrate into the cave," said professor Amos Frumkin of the Hebrew University Department of Geography.
The temperature of the cave water was 88 degrees, 13 degrees warmer than surface water would be in that area, suggesting it was fed by sources from deep inside the earth, said scientists.
``This is the first discovery of terrestrial animals found only in a cave and not on the surface," said Hanan Dimentman of the Hebrew University Alexander Silberman Institute of Life Sciences.
``Ecologically, this is a unique cave unparalleled anywhere else in the world. Water, nutrients, and animals cannot enter from above. It has been isolated from above for millennia," he said.
He said there were no plants in the cavern because the lack of sunlight ruled out photosynthesis, but he had identified several bacteria which served as the basic food which supported the unique life system inside the cave.
``The eight species found thus far are only the beginning" of what promises to be ``a fantastic biodiversity," said Dimentman, adding that he expects further exploration to reveal more unique life forms.
The cave was uncovered during routine digging in a cement quarry near the central Israeli town of Ramle. It has now been closed off to prevent contamination while scientists continue to explore for more life forms.
Despain, the American scientist, said the Israeli find was unusual because the cave was isolated from the outside world and had a unique source of energy.
``There is a similar cave in Romania which is also cut off from the outside though not as deep, which like the Israeli cave also has food sources which come from sulphur compounds in the water. They discovered 20 unique species in that cave," he said.
``It's probably only the second time that an ecosystem of this type has been found intact and functioning. We have indications of similar systems in disused caves but to find them still functioning is extremely rare. They are tremendous laboratories for scientific study."