ShareThisBy DAN SORENSON
Sunday, November 19, 2006
The jury is still out on our effect on Kartchner Cavern's mama bats, but we're a big hit with cave slime.
Since humans started visiting in numbers _ the cave opened in 1999 _ some microscopic cave species are "getting fat and happy," said Raina Maier, a University of Arizona professor of soil, water and environmental science studying the cave's microbes.
Maier heads a UA team recently awarded a five-year, $1.6 million National Science Foundation grant to monitor microbial activity in the caves 50 miles southeast of Tucson.
Although the National Science Foundation-funded portion of the study is just getting under way, Maier said ongoing work at Kartchner shows that the microbes that appear to be thriving aren't directly connected with humans. But, she said, it's likely they're thriving thanks to the nutrients cave visitors leave behind.
She said human visitors inadvertently leave behind skin cells, hair and lint, which can become food for microbes.
In the case of the aforementioned bacterial slime, the manmade dinner is even more disgusting than skin, hair and lint. Maier said what got researchers' attention in the first place was "a copious slime" living and dining on paint that had been applied to Fiberglass housings concealing electrical and plumbing systems.
But in parts of the cave far off the human path, it's apparently still slim picking for microbes. Nearer the human pathways, the microbes are living higher on the hog, though it could not be called "nutrient rich," said Maier.
Oddly enough, though microbes near the human paths appear to be thriving, there are fewer species of microbes close to pathways (22 to date) than in areas more removed from humans (32 species, so far), said Maier.
It is not yet clear how the suspected nutrients get to the microbes, though Maier said she suspects that the lint and skin cells become airborne in the damp cave air and stick to the humid walls, where they become food for the miniature creatures.
Monday night, soon after the last of the day's tourists cleared out, project scientists took samples in trailside and remote sites in Kartchner's Big Room.
Maier said they will return to take samples twice a year, being careful to take samples in exactly the same spots each time.
Microbes _ a broad term encompassing all microscopic organisms _ are of interest to scientists for several reasons, some of them having to do with the health of the cave and others possibly having to do with the health of humans outside.
