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The Middle Miocene Mystery. CAS Assistant Professor of Earth Sciences David Marchant is investigating whether global climate changes are affecting the East Antarctic ice sheet, and if so, how those changes may be affecting the rest of the world.

The recent discovery by Marchant and colleagues of Miocene-age volcanic ash embedded in Antarctic sediment will allow scientists for the first time to reconstruct its precise climate and glaciological conditions 14 million years ago.

"This data is crucial to understanding the conditions that led to abrupt global cooling back then, as well as the emergence of the East Antarctic ice sheet itself," says Marchant. "This in turn will shed light on the implications of current climate changes."

Additional data will be supplied by another, unexpected discovery by Marchant’s team: the oldest fossil glacier ice in the world, formed more than 8.1 million years ago in the Dry Valleys region of Antarctica.

"The presence of Miocene-age ice less than 20 inches below the surface implies that temperatures have never warmed enough during the last 8.1 million years to allow significant melting in this area," he says. "It calls into question the view that during part of the Pliocene Epoch of three to four million years ago, East Antarctica was largely free of glacier ice, but rather points to the development of a polar ice sheet by Middle Miocene time."

The ice also holds samples of the earth’s Miocene-age atmosphere trapped within bubbles. This will enable Marchant to compare the Miocene atmosphere with today’s atmosphere and see how atmospheric chemistry over Antarctica has evolved. He says this will likely be the only data set on earth that records an ancient atmosphere.

Marchant’s work is funded by the National Science Foundation’s Office of Polar Programs.

Mirror, mirror, on the chip. Palm-sized computers and cell phones have put more power and function into ever-smaller packages. Nanotechnology, the art of building devices on the atomic or molecular level, will shrink things even further.

Thomas Bifano, ENG associate professor of mechanical engineering, and colleagues have used nanotechnology to develop a method of arranging tiny mirrors in arrays – up to 200 of them on a chip three millimeters across. Each is able to move precisely and independently.

With their ability to manipulate reflected light, the mirror arrays can be used to substantially improve the resolution of earth-based telescopes that look beyond the atmosphere. They can also be used by physicians to see the retina clearly through the eye’s normally cloudy vitreous liquid, and to improve the quality of wireless communication by using lasers to transmit clearer signals.

Bifano’s lab is also pursuing a multidisciplinary program to develop chips holding high-density protein arrays for basic research, drug discovery, and medical diagnosis.

The primary function of genes is to make proteins, which regulate most biological functions, serve as the principal targets of drugs, and are implicated in many diseases. Proteomics, the study of proteins, is one of the newest and most important fields of biomedical research. Bifano says his micro-mirror systems provide the basis for building the protein array chips. The multidisciplinary research team includes faculty and students from the departments of manufacturing engineering, bioinformatics, biomedical engineering, chemistry, and biology.

"Research Briefs" is written by Janice Zazinski in the Office of Public Relations. To read more about BU research, visit http://www.bu.edu/research.

2 March 2001
Boston University
Office of University Relations