Charting a Sea Change: The Life and Times of Snails and Clams By Marci Janas
	Reefs through Time and Space: Winter Term in St. Croix		FEBRUARY 28, 2000--Think of filmmaker Michael Apted's longitudinal documentation of British schoolchildren through adolescence and adulthood, and you have some idea of what Assistant Professor of Geology Karla Parsons-Hubbard does with snails, clams, and other armored organisms. Instead of time and a camera, however, she uses time and the sea. And a few Oberlin students. The exact nature of her work is taphonomy, which concerns the processes of preservation, especially of mollusks and echinoderms. Put another way: how animals become fossils in the first place. She is part of a larger research group that has placed hundreds of mollusks, urchins, crabs, and woody plants out on the sea floor. At certain intervals the researchers retrieve the organisms, studying the changes wrought by the sea. To deploy and retrieve the samples, which settle deep (as far as 500 meters, or 1800 feet, in some cases), all the work is done from research submersibles. Geology major Christopher Nytch--a senior from Durham, Connecticut, who was part of the St. Croix group--has been working with her, studying epibiont overgrowth found on sea urchin skeletons that Parsons-Hubbard's research group deployed in the Bahamas. (Barnacles covering a wooden pier are an example of epibiont overgrowth.) Nytch's focus has been on the epibiontic overgrowth known as bryozoans, microscopic animals that encrust hard surfaces. "He has done a tremendous amount of work simply identifying the genera," says Parsons-Hubbard. "There are not many bryozoan experts in the world, and I think Chris has been in contact with a majority of them." When asked what a sea urchin skeleton encrusted with bryozoan overgrowth looks like, Nytch jokes, "It looks like a whole lot of data to me!" A photograph he took under a scanning electron microscope tells the pictorial story. Geology major Rebecca Lincoln, a senior from Chicago, is studying the taphonomy of crabs deployed in the Bahamas. Her project, Parsons-Hubbard says, "is a broader look at the overall decay of the crab skeleton with time and depth." Nytch and Lincoln will present their findings at the Geological Society of America's North-Central Conference in Indianapolis in April. Another of Parsons-Hubbard's students, Andrew Madof, a senior from Wynnewood, Pennsylvania, will also present at the conference. His work involves ancient fossil communities in Medina County, Ohio. Parsons-Hubbard will accompany her young assistants to the conference. James Altieri, a TIMARA and geology major who was at St. Croix for Winter Term, has been helping Parsons-Hubbard with studies on gross urchin taphonomy, a project he began in earnest last summer on campus. "We're looking forward to finishing that work," says Parsons-Hubbard, "and getting it published this coming summer." This Thursday, March 2, Parsons-Hubbard will give a lecture on her research for the Oberlin chapter of Sigma Xi, the international honor society of scientific and engineering research. The talk takes place at 12:20 P.M. in Severance, Room 108. How did Parsons-Hubbard ever become interested in this field? "I did a senior honors thesis [as an undergraduate at Beloit College] on a collection of beautifully preserved echinoderms that the college owned. The echinoderms (crinoids, or sea lilies) normally completely fall apart within hours of their death. They have very little tissue holding them together. I wondered, What were the conditions of their death that allowed such incredible preservation? Could their preservation quality help to reconstruct the environment of the sea floor 330 million years ago? It was a fascinating topic."
			Please send comments, questions, and suggestions about Oberlin Online news and feature articles to online.news@oberlin.edu.