Aquifer: A Novel (14 page)

Over thousands of years, flowing groundwater gradually dissolves channels through the limestone. This process can create underground caverns which grow in size until finally, their roofs cannot support the weight of overlying soil and rock. A sinkhole is created when the surface materials either collapse or are dissolved into the underground cavern or cave system.

Reid had done his homework and knew that one of the largest sinkhole systems in the area was formed spontaneously on May 6, 1978 when several large sinkholes opened beneath a 37-acre sewage lagoon serving the city of West Plains, Missouri, only forty miles away. These new sinkholes immediately drained the lagoon’s entire 50-million gallon contents of raw sewage, sucking it underground. From there it was funneled through underground streams and rivers until it eventually returned to the surface again. This time, however, the sewage was disgorged from the mouth of Mammoth Spring, just over the state line in Arkansas, thirty miles away.

Reid had also learned that one of the area’s largest sinkholes, named The Devil’s Well, was located just a few miles north of Round Spring. It had been formed when seeping groundwater eroded the roof of a subterranean cave causing it to collapse. The resulting sinkhole opening was over one hundred and fifty feet across at ground level and narrowed to a constricting funnel opening only twenty-five feet wide which crashed through the cave’s massive domed roof about fifty feet below the surface of the ground. From that point there was nothing but empty air space for another hundred feet. At the bottom of the cavernous room lay a huge, crystal clear underground lake, larger than four football fields in size and over one hundred and twenty-five feet deep.

Yes
, thought Reid,
the sinkhole disguise will work perfectly
. He knew that no one would question the sudden formation of a new sinkhole, even one as large as the crater produced by the alien space craft.

=/\=

C
HAPTER
F
OURTEEN

Chytrid

The darkness of a moonless night settled over the Current River, bringing with it the usual chorus of night songs and other sounds associated with the Ozark riverways. Far in the distance the baying of hounds could be heard as they chased their quarry through the dense forest. Occasional splashes echoed over the river as fish rose to catch their evening meal.

Dr. Clayton and Larry, both decked out in fisherman’s waders, slowly made their way through waist-deep water along the bank in a backwater eddy of the river. The lenses of their flashlights were covered with yellow cellophane. Both of the men were carrying large nets at the end of long poles, somewhat like butterfly nets only considerably more sturdy. They also had specimen collection boxes slung over their shoulders and wore fisherman vests with several zippered and velcro pockets filled with sample vials and assorted miniature tools. Clayton, as was his trademark, wore a tan felt hat with an arching brim that curved down in both the front and back, a combination of a cowboy hat and an Australian bush hat. Larry, in keeping with his generation, wore a baseball cap, backwards.

“I’m still amazed that frogs can’t see yellow light,” Larry whispered.

“Well, they can to a degree but their eyes aren’t very sensitive to it so they are less likely to be alarmed,” Clayton explained in muted tones.

The men crept up on an unsuspecting frog that had puffed up his throat and was singing quite loudly while sitting on a partially submerged log near the bank. Larry slowly brought his net forward until it was about two feet in front of the frog. At that point the wary frog stopped singing and carefully watched the net before him. Then, with his other hand, Larry extended a long pole with a small paddle on its end and brought it up behind the frog. Gently, he tapped the frog on its back with the paddle. The frog leapt forward in an attempt to jump over the net. Larry quickly raised the net, snagged his catch, and rotated the pole ninety degrees to seal the frog inside the net.

He passed the net end of his pole to Clayton who gently removed and immobilized the frog with his left hand while grabbing a pair of small cuticle scissors which hung from a string pinned to his fishing vest with the other hand.

“We haven’t found as much evidence of Chytrid as I had feared,” Clayton commented. “But the infestation rate is still higher than I’d like to see.”

“Since Chytrid is a fungus that normally feeds on dead vegetation, why does it sometimes attack frogs?” asked Larry, as he held the flashlight and focused its beam upon the frog in Clayton’s hand.

Clayton carefully cut off one of the frog’s hind toes and placed the severed toe into a pre-labeled specimen vial.

“No one knows for sure, but we know that it feeds on the Keratin in the frog’s skin.”

“Keratin?” asked Larry, “Isn’t that the protein that creates calluses?”

“Yes,” Clayton responded, as he snapped the lid onto the sample vial. “But in amphibians it also creates those horny epidermal tissues - or warts, as some people call them.”

“So how come Chytrid kills frogs but doesn’t seem to affect other amphibians very much?”

“Well, frogs have very primitive lungs that don’t work very well. Much of their oxygen requirement is obtained by direct absorption through their skin.” Clayton unzipped a pouch in his fishing vest and placed the sealed vial inside. “Since frogs drink and breathe through their skin some researchers believe that the fungus kills them by disrupting these mechanisms. However, several of my colleagues and I believe that Chytrid is actually a relatively harmless parasite in and of itself. It just happens to produce an extremely toxic waste by-product which is especially lethal to frogs,” explained Clayton, letting go of the now empty net and pointing to the next victim poised on a log about ten feet to their left.

“So instead of asphyxiating them it poisons them?

“That’s what I believe, and I’d like to prove it.”

“What difference does it make? Either way the frogs still die.” Larry extended the netted pole. He then prodded the next unsuspecting frog with the long paddle and snared another captive.

“True, but the method of death could prove significant in how pollution affects them. But that’s one of the side projects to work on after this summer’s research is completed.”

“Well, poisoning would make sense,” Larry commented as he passed the net to Clayton with the newest victim awaiting toe amputation. “Many types of fungus are harmless while producing deadly toxins. Like toxic black mold that sometimes invade homes making them impossible for the family to remain there.”

“Yes, you’re seeing the pattern. An interesting anomaly about frogs, though, is that tadpoles only have keratin in their mouths. So though they may carry the fungus in their mouths, they will not succumb to it, at least not while they are young. But once they metamorphose into a frog, the fungus can take hold and kill it.”

“That’s interesting,” said Larry. “So the tadpoles are like little
Typhoid Marys
spreading the disease throughout the population, culminating in their own deaths when they reach adulthood.”

“That’s right,” Clayton responded, releasing the most recent frog victim back into the water. “If the fungus gets out of control it can totally destroy an entire species in a matter of a few weeks. We’ve tried to develop a preventative drug, but so far we’ve been totally unsuccessful. I’m afraid we’re years away from prophylaxes.”

“Isn't there another way to monitor for the fungus . . . I mean besides . . .?” Larry raised his right hand and formed a “V” with his index and middle fingers and quickly opened and closed his fingers as if they were a pair of scissors.

“Unfortunately for the frogs, no.” The men started wading toward another log several feet away. “We must either kill them and perform a histological examination, or cut off a toe and examine it back at the lab. We suspect that tannic acid leaches from the logger's sawdust piles and gets into the water supply. It apparently weakens the frog's natural defenses which allows the Chytrid to take root.”

Larry had just passed the net end of his pole to Clayton when an unusual noise caught Clayton’s ear. It was faint and appeared to come from fifty yards or so from the woods behind them. Being a zoologist and spending much of his professional life on location in one wildlife area or another, Clayton had become quite accustomed to all of the noises that nature produces. This was not one of them.

“Did you hear that?” whispered Clayton. He was not alarmed, just curious.

“How can you expect me to hear anything over the racket of these frogs and cicadas?” Larry protested. “What did it sound like?”

“I’m not sure. It was a sound I couldn’t place but it seemed mechanical . . . a snap, a click, something short and abrupt,” Clayton replied while completing the amputation and releasing the previously captured specimen.

Larry proceeded to sneak up on another unsuspecting frog but Clayton remained distracted. He glanced around their surroundings, searching for anything that could have produced the curious sound. Simultaneously, his mind unsuccessfully searched for a match.
Where had he heard that sound before
? But his mental search was futile.

Larry netted another unsuspecting quarry and passed the net end of his pole to Clayton, who absent-mindedly began the process of removing the new captive from the net. With his left hand, Larry raised his flashlight and shined the cellophaned beam onto the frog so that Clayton could use both of his hands to free it. But when the light’s beam struck the frog Larry was shocked to see that the frog had three hind legs and one of its eyes was in the middle of its back instead of in the usual eye socket.

“Whoa! A mutant!” exclaimed Larry.

“Damnable loggers!” muttered Clayton. “Their tannic acid pollution causes mutations like this if it comes into direct contact with developing eggs. We need tougher environmental laws to prevent stuff like this,” he ranted disgustedly. In his anger he forgot all about the strange sound. He became so absorbed in venting that he did not hear the click of the lens cap snapping into place as a stalker replaced the night vision goggles into its carrying case and silently retreated deeper into the woods.

*

The next morning, Sunday, Clayton and Larry examined the toe clippings collected during their previous nocturnal excursion. They used an array of oils and stains which they dropped onto cross sections of the toe specimens while examining them under a microscope. The stains highlighted the Chytrid organisms and facilitated searching for and identifying them.

All Chytrids belong to the microscopic fungal division of the most primitive fungi,
chytridiomycetes
. There are thousands of different types of Chytrid organisms spread over several phylum, order, genus and species. Chytrid organisms (pronounced
kít-rid
), can be very destructive to the agricultural industry, especially to corn and hay. Other strains of the organism are aquatic, though they prefer fresh water to brackish. Most Chytrids are totally harmless to frogs. The ones that aren’t, however, are deadly – 100% of the time. The time from infection to death is generally one to two weeks for any given frog and four to six weeks for an entire population.

Frogs in both North and South America have co-existed for thousands of years with hundreds of harmless strains of Chytrid organisms. It is believed that the newly introduced killer strains came from Africa in the late 1970s or early 1980s, probably introduced by the importation of pet frogs from that region. Since then many of the native amphibian populations, and especially frogs, have been greatly decimated by the foreign microscopic fungi.

“I’ve never seen a full blown Chytrid infection. What happens?” asked Larry.

Clayton continued working on toe specimens and answered while he peered through the microscope dropping stains onto the microscope slide. “Well, the frog’s skin sloughs off as the fungus eats away the keratin. Their bellies usually turn a reddish color and they become lethargic. The fungus also damages the nervous system, affecting their behavior. When they move they often become very clumsy, tripping over themselves. When the neurological signs appear they usually die within 10-12 hours.” Clayton raised his head from the microscope and peered very seriously at Larry. “Once you get a few frogs that have advanced to that stage it is usually too late. The whole population will be gone in a matter of a few weeks, and there’s nothing we can do to stop it.”

Pausing momentarily, Clayton made a few notes in his log, removed the slide from the microscope and snapped a fresh one into place. He placed a drop of reagent upon a new specimen, made a couple of adjustments in the focus of the microscope and then continued, “Fortunately, unless the frogs are extremely stressed, the Chytrid remains on their toes where their immune systems can fight it pretty well.”

“I’ve noticed that there’s more Chytrid on the toes of the frogs from the Current River than the ones from the Jack’s Fork,” Larry noted.

“That’s right. The Current River is spring-fed with cold water. Chytrid likes it cold.”

Larry glanced at the clock, which read 12:30 in the afternoon. “We should start cleaning up. We've only got thirty minutes to get to the Chitwood’s.”

“I’ve nothing in common with these backwoods, uneducated, country folks. You go on, I'll stay here and work,” protested Clayton.