PUBLICATIONS Inside Illinois Vol. 20, No. 11, Dec. 7, 2000

''Cool' finds
Geology professor digs finding Antarctic fossils

James E. Kloeppel, News Bureau Staff Writer
(217) 244-1073; kloeppel@illinois.edu

Base Camp This field station on Seymour Island in Antarctica served as the research base from which fossil-collecting expeditions were launched on previous excursions. During this trip – UI geologist Dan Blake's third – the crew will be based on a ship from which the fossils will be cataloged and packed for shipment.

Geologist Dan Blake is not dreaming of a white Christmas. In fact, he’s dreading snow in December. That’s because Blake, a professor from the UI, hopes to be collecting fossils on a small island off the Antarctic Peninsula, and a blanket of snow would stop his work cold.

Although December falls during summer in the Southern Hemisphere, the Antarctic weather will be far from warm, with temperatures hovering near freezing. "Any snowfall will cover the fossils and halt our collecting," he said. "Then, all we can do is sit around and hope that it melts before we have to head home."

In addition to the occasional blizzard, the expedition to Seymour Island presents other hazards as well. "Antarctica is not a user friendly place," said Blake, who had to pass a rigorous health exam as a requirement for going on the trip. "It’s not necessarily unsafe, but you must be careful and avoid risks. If you get into serious trouble, the nearest physician is thousands of miles away."

This will be Blake’s third trip to Seymour Island. During previous expeditions, he and colleague Richard Aronson – a marine biologist at the Dauphin Island Sea Lab in Alabama – documented how a long-term trend of declining temperature in Antarctica at the end of the Eocene epoch disrupted certain predator-prey relationships.

Local resident Penguins are one of the local residents of Seymour Island, which is about 13 miles long and from 2 to 5 miles wide. It is called an "oasis" because it has extensive dry valleys with bare rock and little snow. Volcanic dust deposited within the valleys promotes the melting of any snow and ice, leading to further exposure of the rock surface, which makes it ideal for collecting fossils.

Global climate change late in the Eocene had an important influence in Antarctica. "This was the beginning of the transition from a cool-temperate climate in Antarctica to the polar climate that exists there today," Blake said. "The cooling trend strongly

influenced the structure of shallow-water communities, and these effects are still evident in the peculiar ecological relationships among species living today."

The researchers’ early work concentrated on populations of crinoids and brittlestars. "We argued that as the temperature cooled, it upset the balance of nature and resulted in reduced predation," Blake said. "Now we want to go back and examine effects of predation in more detail by studying populations of other organisms – specifically snails and clams."

Some of the snails the researchers are interested in earned their livelihood by drilling holes in the shells of clams and extracting the tender meat inside. Cooling temperatures reduced the abundance of fish and crabs, which in turn altered predation patterns of the snails that fed upon the clams. A number of outcomes of these changes are possible, each of which will be interpreted differently.

"For example, the drilling of clams by predatory snails could increase with time, since the drillers themselves were subject to lower predation pressure as temperatures declined," Blake said. "Drilled shells in this outcome will become more common through time. We will look for and compare such changes in predation rates as we walk through the stratigraphic section and across the climatic change revealed in the rocks."

The fossil record has many exciting things to say about both past and present marine ecology, Blake said. "The fossil outcrops on Seymour Island provide a unique opportunity to learn how climate change affected Antarctic marine communities. Understanding the response of fossil faunas to global cooling in the late Eocene will provide insight into the rapidly changing structure of modern communities."

Funded by the National Science Foundation, this year’s trip will involve a weeklong reconnaissance mission on the island – in preparation for a five-week-long fossil-hunting expedition to occur next year. The research team includes Blake, Aronson and Blake’s graduate student, Alex Glass.

"It’s very important for students to go on such field expeditions," Blake said. "In addition to the adventure, they can learn an aspect of geology that they just can’t learn in the laboratory … as long as it doesn’t snow."