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Burdige Research Findings Ranked 12th Most Important for 2009 by Discover Magazine

David Burdige

Discover magazine has ranked geological research findings of Old Dominion University faculty member David Burdige as the 12th most important discovery of 2009.

Burdige, an expert in biogeochemical oceanography and an ODU professor and eminent scholar of ocean, earth and atmospheric sciences, won the distinction for research findings reporting the earliest geological evidence for animals on Earth.

An article he wrote with colleagues in the May 2009 issue of Geology magazine places the existence of multicellular organisms around 800 million years ago, which is several million years earlier than the previously reported fossil or geochemical evidence of animals.

Canadian geologist Fritz Neuweiler of Laval University in Quebec is the first author of the article and Elizabeth Turner, a paleontologist from Laurentian University in Ontario, is also an author. The journal Geology is published by the Geological Society of America.

Discover magazine (see http://discover.coverleaf.com/discovermagazine/20100102?pg=36#pg36) notes that the origin of animals has long perplexed scientists. "DNA studies of creatures living today suggest that their common ancestor appeared nearly 800 million years ago, yet the fossil record contains no clear evidence of animals more than 555 million years old," the magazine states.

The discovery reported in Geology, and another similar discovery reported in the journal Nature, "are starting to resolve that apparent conflict," according to Discover.

In addition to the Discover ranking, Quebec Science magazine named the findings of Neuweiler, Turner and Burdige as one of the top 10 scientific discoveries of 2009.

The research team found evidence in the Northwest Territories of Canada indicating that primitive, sponge-like organisms existed during a period known as the Neoproterozoic interval of "hidden evolution." The Neoproterozoic age was from about 779 to 1,083 million years ago.

The scientists describe microscopic features they found in limestone about 800 million years old that are much like the texture known to develop today when aragonite crystals precipitate on the decaying connective tissue of sponges in sediment on the sea floor.

A complex texture of calcareous material and voids is produced as sponges decay in sediment at the ocean floor. This texture identified in modern sediments has been shown previously to be identical to those found in limestone about 500 million years old. Now, Neuweiler, Turner and Burdige have produced evidence of the texture in limestone that is several hundred million of years older. Their samples came from the Little Dal formation, which is renowned among geologists for its well-preserved record of Earth's evolution.

The animals, known as metazoans, that would have produced this new evidence did not have the canal system of sponges, which are the simplest form of animal life known today. The scientists say the organisms likely were a structured consortium of protists living in a shared scaffold of extra-cellular collagenous matrix up to a size of several centimeters.

The scientists note that an alternative interpretation of their evidence cannot be ruled out, but that features of the Little Dal reef indicate that the samples were not produced by macroalgae or some other grouping of unicellular organisms too small and simple to be animals. They describe their findings as "intriguing enough to stimulate further research aimed at unraveling the interval of hidden evolution, beyond the limits defined by conspicuous body fossils or metazoan biominerals."

Burdige and Neuweiler have collaborated previously on articles in the Journal of Sedimentary Research and the journal Sedimentary Geology, reporting research findings related to the calcification of sponges on the Great Bahama Bank. They began their collaboration in 2004 when Neuweiler was awarded a fellowship to work in Burdige's lab learning the fluorescence techniques that eventually formed the basis of the work presented in this article.

Burdige served as vice chair of the August 2009 Gordon Research Conference on Chemical Oceanography in Tilton, N.H., and will be chair of the 2011 biennial meeting. The chemical oceanography conference, which has been held since 1969, is part of the Gordon Research Conferences (GRC) lineup of international forums in biological, chemical and physical sciences. GRC is a nonprofit organization managed by and for the benefit of the scientific community.

The research of the ODU scientist focuses on biogeochemical processes in estuarine and marine sediments. He is the author of the textbook "Geochemistry of Marine Sediments," published in 2006 by Princeton University Press.

This article was posted on: January 25, 2010

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