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Blacksburg, Va. -- Tiny tropical plants survived their continental-drift relocation to the Arctic by adapting to its harsh climate. Research into such adaptations of millennia ago, when ancient tropical continents drifted into frigid climes, helps understand "the steps of wisdom of life," said Stephen Scheckler, professor of botany in the Department of Biology at Virginia Tech.
Scheckler spends July of each year close to the top of the world, on Ellesmere Island next to the top of Greenland and on nearby Melville Island, where the sun shines 24 hours a day. Scheckler and his co-researchers are locating and collecting fossils for studies with James Basinger, head of geological sciences at the University of Saskatchewan. Through loan from that university, Scheckler obtains some of the fossils for his and his students' research. "It is important to study the Arctic because, climatically, it will change the most and that change will influence the rest of the planet in an accelerating way," he said.
Even when it is summer, the ground is permanently frozen, thawing only six inches deep at its warmest. Because the area is remote and desolate, no one can go alone, and the scientists must contact base twice a day or search parties will start looking for them. They live near a source of water, in tents, and store perishables in the thawed permafrost, hoping the foxes, wolves, and bears don’t get them. They never leave camp without a gun because of polar bears, but cannot shoot unless their lives are in imminent danger.
The scientists walk or travel by all-terrain vehicles 10 or more miles from camp daily to hammer out and bring back ancient fossils that sometimes resemble parsley or dill or fern, but look odd because the leaves are small and dissected. The researchers look mainly along rivers that have eroded the permafrost back, exposing the fossils.
With funding from the National Science Foundation and the Polar Continental Shelf Programme and a partnership with Basinger, Scheckler is looking at plants and how they adapted when the continents shifted around to different paleoclimates during the mid to late Devonian period. In this ancient world, plants were much more alike because they grew in tropical forests. As the continents shuffled around, the plants had to change or die. Scheckler’s hypothesis is that plants have been adapting ever since there have been plants.
"If we know the paleo-ecology of the ancient world, we can predict where there should have been tropical forests, frosts, and other such things," Scheckler said. "What we see as we recover fossil plants from these different locations in the modern world perhaps can help us understand how they adapted to different climates at that time."
When they go to the Arctic, Scheckler and his colleagues are looking for fossils that provide one of two types of information: 1) identity or the kinds of plants—the community of plants as compared to those from other places of the world, or 2) the potential to reveal the biology of a plant—how it grows and reproduces. Besides actual fossils, the scientists also bring back photos and field notes of their Arctic expeditions.
"We’re trying to understand the vegetation diversity of ancient times," Scheckler said.
They frequently find plants never seen before and can study how they are organized and what other plants they could be related to, information that can tell how the plants evolved and adapted to different areas. As plants moved into colder regions, they began to reflect more of their environment, Scheckler said.
"If there’s adequate rainfall, they will grow big," he said. "That way, we can tell when there was rain. If there was enough sun, they will have different kinds of leaves than they would have in a short growing season. We can tell how plants are adapting by how they are constructed. We can understand the steps needed for plants to specialize for diverse environments. The complexity of the roots, stems, and leaves tells us what the microenvironment was like and how they were covering the land."
The scientists, too, are studying possible causes of extinctions, both animal and plant. If they can find fossils, they can add to the information used in debates about whether some extinctions are caused by traumatic events such as asteroids, or whether other extinctions are a gradual process that results from climate changes at a particular time and place.
"We’re looking at floristic changes to see what’s been going on," he said. He thinks extinctions didn’t happen all at once. "Something was going on before the asteroid."
Scheckler’s work helps understand how the Earth rebounds from big extinctions, what organisms are susceptible to extinction and why. "People in the U.S. are beginning to track near-Earth orbiting asteroids in the solar system to see which will come near Earth’s orbit in the next 50 years," he said. "The planet would be entirely different after than before an extinction."
With model plants, the scientists also can develop ecological models of carbon cycling. Scheckler is looking at land when forests first appeared, a time when carbon dioxide went from high to low. "Now we’re in the opposite scenario, the deforestation of land for agriculture or sale of wood or creation of living space. At the same time, many farms are being abandoned and vegetation and trees are re-growing, but they are deforesting faster than the land is replenishing. I predict that carbon dioxide will go closer to its original high," Scheckler said.
Plants, animals, and Earth events create a delicate balance of creating and using carbon dioxide. "If we mess with one of the components, equilibrium can be higher or lower," Scheckler said. At present, in North Africa, China, North America and South America, forests are being cut down. "We’re fiddling with that equilibrium," Scheckler said. And if carbon dioxide in the air reaches 5 percent, "we’ll all be unconscious."
Even if his work had no relevance to current events, knowledge of fossils, of history, is important, Scheckler said. "Before humans, the Earth had a history, and we’re concerned about that history. The magic of creation is important. We’re seeing the stages of the wisdom of life."
PR CONTACT: Sally Harris, (540) 231-6759 slharris@vt.edu