Post by L Roebuck on Sept 15, 2006 7:19:47 GMT -5
Strange array of creatures lies under Alabama
UA scientists to study ecosystems
Friday, September 15, 2006
KATHERINE BOUMA
News staff writer
Beneath Alabama are creatures as strange and unexamined as any on Earth, animals living with no known source of food - blind and nearly invisible fish, shrimp, crayfish and salamanders.
Alabama has more caves than any other state. And scientists believe those subterranean ecosystems cradle the nation's greatest diversity of groundwater creatures.
But they know little beyond that. Life underground is an area that has been, until now, largely ignored by biologists.
While cavers have enthusiastically embraced the sport of exploring underground Alabama, ecologists qualified to study wildlife have rarely followed.
A pair of University of Alabama professors plan to change that, beginning with research funded by a three-year state wildlife grant.
"We're going to be able to answer a lot of questions with this study," said biology Professor Bernard Kuhajda. "It's the great unknown."
Kuhajda has already discovered how little is known about life in Alabama's caves. Although he is not an expert in crustaceans, in 1999 he discovered a new species of shrimp in two caves just west of Tuscumbia.
"That's caving," he said. "You just never know what you're going to find."
He and colleague Alex Huryn believe their research will raise even more questions than it answers. As they delve into the caves, they hope to find creatures and habitats that lead to more reasons to study until they can expand their work to the entire underground freshwater ecosystem.
Amazing finds:
They are beginning by chasing something of a fish tale.
Huryn got hooked on underground exploration when he went caving with Kuhajda to try to find a spot appropriate for a field trip for his freshwater ecology class.
Already an expert on crayfish, he was amazed to find large, white creatures that, with their outsized limbs and antennae, look something like miniature albino lobsters.
Searching the literature to see what was known about the cave crayfish, he found that a graduate student had written his dissertation in the early 1970s on the same species. The student measured the 2- to 3-inch animals, marked them, returned them, captured them again and measured them some more.
From their rate of growth, he concluded that the crayfish live for 100 years - as much as 25 times as long as their above-ground relatives. If that were correct, a graduate student would have discovered one of the world's longest-lived species. So it's somewhat surprising that he never published the findings.
"I wonder if he wasn't skeptical himself," Huryn said. "But he found how much they grow over the years by measuring them and recapturing them. And they just grow very, very slowly. There's no doubt about that."
Underground, animals are known to have slower metabolisms, which would lead to longer lives.
"Long-lived animals have low reproductive rates, (and) are going to be very susceptible to anything that affects their environment," Huryn said. "If these animals are super long-lived, and they don't move around very well, then once a population is knocked out, it's going to take a long, long time for that thing to recover. It's going to be a lot different from something that reproduces every year."
A pesticide spill, for example, could wipe out an entire population, captive and unable to rebound.
Besides finding out how quickly they grow, the biologists hope to learn how the cave dwellers survive, since there's no obvious source of food underground.
"On the surface, it's the sun that drives all growth," Kuhajda said. "Things eat plants, and those things eat other things. In the cave, all the energy has to be brought in from other sources."
Sometimes the only obvious source of nutrients is bat guano, so the pair is studying whether growth rates are faster in caves with a bat colony. In pit caves, rain can wash down leaves, sticks and nutrients from above.
"Energy has to get into the cave somehow, and we really don't know how," Kuhajda said.
Underground world:
Caves have been left alone, in part, because underground exploration is so difficult.
"There are 4,000 caves in Alabama, and most of them have not been searched," said James Godwin, an aquatic zoologist for the state. "Biologically, they've hardly been touched."
He and other biologists guess that only 200 of the caves have been entered for biological exploration.
Scientists already know where limestone formations are right for formation of caves, and they have maps showing where the groundwater is running under their feet. For years, they have had access to dye tests that reveal where the groundwater flows and which caves it connects.
But the caves aren't the entire underground. They're actually a small portion of the subterranean world - windows and entryways into what lies below.
Kuhajda compares studying the underground via caves to researching a vast forest by peering in from the edge of a parking lot.
Kuhajda and Huryn, with cavers often volunteering as guides, rappel into pit caves, slide through narrow openings and snorkel in rivers and pools, wearing headlights. But they cannot plunge to the depths of the underground waters or follow rivers when they disappear into limestone.
Scientists often have no idea of the depth or length of the waters they are studying. And they usually are searching them using only headlights or flashlights, looking for pale or translucent animals.
Colors are unnecessary in the deep, black underground, where all the permanent residents are sightless. Even when they locate the animals, scientists can be deceived by the lack of color.
Many species appear so similar that only a genetic test shows that they differ.
"All these organisms evolve toward the same kind of body form," Kuhajda said. "You lose your eyes, lose your color, expand your tactile senses. So all these cave critters are going to look pretty much the same."
Biologists do have a good idea why Alabama's caves are among the world's most aquatically diverse.
During the last ice age, the glaciers that covered the upper half of the continent never reached this far south. So the animals of Alabama's caves were able to thrive and continue to evolve for thousands of years longer than others, in the dark, unchanging underground.
To biologists, it's important to find them and note their presence. The cave species are part of a larger ecosystem in which no one knows precisely which ones serve which function - which ones might be the key to the clean groundwater or the continuation of the ecosystem, Kuhajda said.
But to him, he admits, study and protection of cave creatures is far more basic: "They're just really cool, and I want them around."
E-mail: kbouma@bhamnews.com
Article
UA scientists to study ecosystems
Friday, September 15, 2006
KATHERINE BOUMA
News staff writer
Beneath Alabama are creatures as strange and unexamined as any on Earth, animals living with no known source of food - blind and nearly invisible fish, shrimp, crayfish and salamanders.
Alabama has more caves than any other state. And scientists believe those subterranean ecosystems cradle the nation's greatest diversity of groundwater creatures.
But they know little beyond that. Life underground is an area that has been, until now, largely ignored by biologists.
While cavers have enthusiastically embraced the sport of exploring underground Alabama, ecologists qualified to study wildlife have rarely followed.
A pair of University of Alabama professors plan to change that, beginning with research funded by a three-year state wildlife grant.
"We're going to be able to answer a lot of questions with this study," said biology Professor Bernard Kuhajda. "It's the great unknown."
Kuhajda has already discovered how little is known about life in Alabama's caves. Although he is not an expert in crustaceans, in 1999 he discovered a new species of shrimp in two caves just west of Tuscumbia.
"That's caving," he said. "You just never know what you're going to find."
He and colleague Alex Huryn believe their research will raise even more questions than it answers. As they delve into the caves, they hope to find creatures and habitats that lead to more reasons to study until they can expand their work to the entire underground freshwater ecosystem.
Amazing finds:
They are beginning by chasing something of a fish tale.
Huryn got hooked on underground exploration when he went caving with Kuhajda to try to find a spot appropriate for a field trip for his freshwater ecology class.
Already an expert on crayfish, he was amazed to find large, white creatures that, with their outsized limbs and antennae, look something like miniature albino lobsters.
Searching the literature to see what was known about the cave crayfish, he found that a graduate student had written his dissertation in the early 1970s on the same species. The student measured the 2- to 3-inch animals, marked them, returned them, captured them again and measured them some more.
From their rate of growth, he concluded that the crayfish live for 100 years - as much as 25 times as long as their above-ground relatives. If that were correct, a graduate student would have discovered one of the world's longest-lived species. So it's somewhat surprising that he never published the findings.
"I wonder if he wasn't skeptical himself," Huryn said. "But he found how much they grow over the years by measuring them and recapturing them. And they just grow very, very slowly. There's no doubt about that."
Underground, animals are known to have slower metabolisms, which would lead to longer lives.
"Long-lived animals have low reproductive rates, (and) are going to be very susceptible to anything that affects their environment," Huryn said. "If these animals are super long-lived, and they don't move around very well, then once a population is knocked out, it's going to take a long, long time for that thing to recover. It's going to be a lot different from something that reproduces every year."
A pesticide spill, for example, could wipe out an entire population, captive and unable to rebound.
Besides finding out how quickly they grow, the biologists hope to learn how the cave dwellers survive, since there's no obvious source of food underground.
"On the surface, it's the sun that drives all growth," Kuhajda said. "Things eat plants, and those things eat other things. In the cave, all the energy has to be brought in from other sources."
Sometimes the only obvious source of nutrients is bat guano, so the pair is studying whether growth rates are faster in caves with a bat colony. In pit caves, rain can wash down leaves, sticks and nutrients from above.
"Energy has to get into the cave somehow, and we really don't know how," Kuhajda said.
Underground world:
Caves have been left alone, in part, because underground exploration is so difficult.
"There are 4,000 caves in Alabama, and most of them have not been searched," said James Godwin, an aquatic zoologist for the state. "Biologically, they've hardly been touched."
He and other biologists guess that only 200 of the caves have been entered for biological exploration.
Scientists already know where limestone formations are right for formation of caves, and they have maps showing where the groundwater is running under their feet. For years, they have had access to dye tests that reveal where the groundwater flows and which caves it connects.
But the caves aren't the entire underground. They're actually a small portion of the subterranean world - windows and entryways into what lies below.
Kuhajda compares studying the underground via caves to researching a vast forest by peering in from the edge of a parking lot.
Kuhajda and Huryn, with cavers often volunteering as guides, rappel into pit caves, slide through narrow openings and snorkel in rivers and pools, wearing headlights. But they cannot plunge to the depths of the underground waters or follow rivers when they disappear into limestone.
Scientists often have no idea of the depth or length of the waters they are studying. And they usually are searching them using only headlights or flashlights, looking for pale or translucent animals.
Colors are unnecessary in the deep, black underground, where all the permanent residents are sightless. Even when they locate the animals, scientists can be deceived by the lack of color.
Many species appear so similar that only a genetic test shows that they differ.
"All these organisms evolve toward the same kind of body form," Kuhajda said. "You lose your eyes, lose your color, expand your tactile senses. So all these cave critters are going to look pretty much the same."
Biologists do have a good idea why Alabama's caves are among the world's most aquatically diverse.
During the last ice age, the glaciers that covered the upper half of the continent never reached this far south. So the animals of Alabama's caves were able to thrive and continue to evolve for thousands of years longer than others, in the dark, unchanging underground.
To biologists, it's important to find them and note their presence. The cave species are part of a larger ecosystem in which no one knows precisely which ones serve which function - which ones might be the key to the clean groundwater or the continuation of the ecosystem, Kuhajda said.
But to him, he admits, study and protection of cave creatures is far more basic: "They're just really cool, and I want them around."
E-mail: kbouma@bhamnews.com
Article