The Archives of the World
A professor is on a quest to discover how the environment has controlled life on Earth, and how life adapts and even alters the environment, for better or for worse.
Amanz Gressly, a quiet, quirky man, regularly set off on hikes in the Alps, disappearing for months at a time. This Swiss geologist would spend the night wherever he could, in a barn or house, and he lived simply and frugally, filling his pockets with fossils as he went.
On one trek in the 1830s, Gressly noticed that the beautiful rocks in the Alps were full of corals, and he concluded that there used to be an ocean there. He also realized that by studying layers of rocks, you could reconstruct ancient environments. Gressly was a pioneer in sedimentology, and he continues to inspire researchers such as Bruce Fouke, University of Illinois geologist and microbiologist.
Like Gressly, Fouke’s research takes him to some of the most stunning environments in the world: the colorful coral reefs of the Caribbean island of Curaçao; the blindingly white deposits of travertine in Yellowstone National Park; and the dramatic arches of the Roman aqueducts in Italy. But Fouke says the thread running through all of his projects is the kind of work begun by Gressly. He seeks the past by studying today’s “rock record,” or what some have called “the archives of the world.”
Fouke’s quest is to discover how the environment has controlled life on Earth, and how life adapts and even alters the environment, for better or for worse. His team sometimes takes about 1,000 photographs in a single day, using the images as a stunning data repository. These pages display just a small sample.
Battling Black Band Disease with Black Boxes
It begins with a small black pinpoint of infection on the top of healthy “coral heads” along the reef tract of the southern Caribbean island of Curaçao. Unchecked, black band disease spreads down and out as a thick black ring, stripping away the coral’s tissue and leaving behind a naked coral skeleton.
“It’s like a flesh-eating lesion,” says Fouke.
Illinois researchers discovered that a community of bacteria, some of which come from human sewage, is the source of the problem. They also discovered that putting coral inside a box could combat the deadly disease. By covering the infected coral heads, they block the sunlight and kill the bacterial culprits behind black band disease. Researchers cover the coral for four or five days, which is enough to kill the bacteria without harming the coral itself.
Updating the Story of Roman Ruins
Rome wasn’t built in a day, and its infrastructure didn’t fall in a day—or even in a few hundred years. In fact, Illinois geologists have found that the most famous component of the Roman infrastructure—the aqueducts—actually survived and functioned as much as 400 years longer than once supposed.
Historians long believed that the famous Roman aqueducts stopped flowing in 537 A.D. after Ostrogoths breeched the walls of Rome. But after studying the steady buildup of travertine deposition within the aqueducts, Illinois researchers concluded that they continued to flow until nearly 950 A.D.—another 400 years after the barbarian conquest.
It makes sense, says Fouke, that Ostrogoths wouldn’t destroy the Roman infrastructure, such as the aqueducts. They would want to keep using this remarkable system, which moved spring water from the Apennine Mountains to Rome.
Fouke and his colleagues study travertine deposits within the aqueducts to answer many other questions about the water and the time period. What kinds of microbes lived in the water at the time? Were they photosynthetic? What were the depth, flow rate, and temperature of the water?
“We can reconstruct all of this from the rock record,” Fouke says.
From Yellowstone to Mars
Yellowstone National Park is best known for its macro-scale wildlife, such as bears, elk, and bison, but the park also teems with life on a micro scale. Illinois researchers are studying fossilized remains of these tiny creatures to get a clearer picture of the prehistoric past—research that is now playing a role in the search for life on Mars by the Curiosity Rover.
Travertine is a form of limestone on dramatic display in the terraced hot springs of Yellowstone. Illinois researchers study travertine to document how microbes become fossilized in the rocks—a process that tells scientists a wealth of information about the environmental conditions experienced by heat-loving microbes in the geological past.
“Yellowstone is a great natural laboratory,” says Fouke.
By studying the fossil record of bacteria in travertine deposits, Illinois researchers have also helped to identify what is and is not a fossilized microbe, which is difficult to do. Understanding how to identify fossilized microbes on Earth will help to identify microbial fossils on Mars, should they be discovered from current rover drilling activities into the crust of the Red Planet.
By Doug Peterson