Today's Oldest Living Things
from the book, "Petrified Lightning"

Book: 
Petrified Lightning

Today's Oldest Living Things

A little over 7,000 years ago bacterial spores were embedded in mud lining Elk Lake in present—day Minnesota. Scientists from the United States Geological Survey collected samples of this mud in 1988. In the laboratory they warmed the spores to surface air temperature and put them in a nutrient—rich culture where, to quote one of the scientists, "They grew like crazy!" After 70 centuries they were still alive; they had survived by living in a frozen state of suspended animation. The scientists were sure they had discovered the oldest living things. And they were right, at least for a short time.

In 1992 scientists discovered what could be the largest and nearly the oldest living thing on earth. The organism is a giant fungus, an interwoven filigree of mushrooms and rootlike tentacles spawned by a single fertilized spore nearly 10,000 years ago at the close of the last ice age. It's come a long way from that single spore, for it now extends over more than 30 acres in the soil of a forest near Crystal Falls, Michigan, along the Wisconsin border.

The fungus Armillaria bulbosa is genetically uniform from one end of its expanse to the other, which is why scientists say it rightly deserves to be called a single individual. If all its mushrooms and tendrils are considered together, the fungus weighs about 100 tons, about as much as the more compact blue whale. The organism survives by feeding on dead wood and other detritus, spreading outward right beneath the surface as it senses the presence of nutrients nearby.

To quote one leading fungus researcher's comments on this discovery, "The catchy part of it is, when you really begin to appreciate how large this thing is, it's mind—boggling. People usually think of a mushroom as a little creature, but most of the action of a fungus is underground." It is almost the world's oldest living thing but not quite.

The Michigan mushroom probably got its start several years after a California creosote bush sprouted in the East Mohave. This complex growing in Soggy Dry Lake has colonized the area with a circle of bushes 25 meters (over 81 feet) in diameter. Any creosote bush that has become established in an arid area captures moisture so efficiently that no other plant can grow near, not even another creosote bush. The individual bush takes over the area by sending out new stems around its base, to be nourished by the spreading underground roots. All are part of the single organism. The current circle of creosotes suggests that this single organism has been growing and expanding for over 10,000 years.

Centuries ago an ailing mastodon stumbled onto the grounds of what is at present the Burning Tree Golf Course, located about 25 miles east of Columbus, Ohio. The mastodon came there to die. Perhaps the moisture of what is still a peat bog felt soothing to its aching body as it lay down and soon breathed its last.

The carcass of the mastodon was slowly engulfed in the bog and buried by subsequent deposits of silt and clay. Much of the body was preserved in its original state. Eons later, in 1989 to be precise, workers excavating the peat bog to create a small lake between the 11th and 15th tees uncovered the remains of the fossil mastodon.

Authorities, hurriedly consulted, excavated the mastodon's remains scientifically. In the abdominal region of the skeleton were the remains of the mastodon's last meal. It consisted mainly of swamp grass, leaves, small branches of pine trees, and seeds. The plant material was traced back to the time of the last ice age. Radiometric dating of the wood from the mastodon's meal indicated an age of about 11,500 years.

Enclosed in the woody material near the ribs was a reddish—brown cylinder of malodorous material. Back in the laboratory, analysis of this foul—smelling, decaying material revealed it to be tens of thousands of bacteria. These single—celled organisms were identified as two strains of Enterobacter cloacae, bacteria commonly found in the intestinal tracts of mammals to aid in digestion. They were cultured by the scientists because, amazingly, they were still alive!

After searching for, and not finding, the bacteria in 12 soil samples from the excavation site, the scientists determined that they did not come from the surrounding soil. A second, "blind" analysis by another laboratory in Columbus confirmed these negative results. The bacterial strain definitely came from within the mastodon. The bacteria had survived because they were sealed under clay and sediment. The bog water entrapping them slowed down the bacterial growth enough to cause them to go into a state of suspended animation.

At the moment that these minute bacteria awakened from their 11,500—year nap, they became the oldest living things. Until another organism, most likely a bacterium or fungus, is discovered in some airtight bog or layer of permafrost that is more ancient, these E. cloacae will continue to hold the geriatric record.