Giosan and colleagues approached the question in a new way. Instead of looking underwater, like previous studies have done, they drilled a 42-meter (140-foot) hole in the Danube delta -- a flat plain that has formed out of sediments deposited by the Danube River as it pours into the Black Sea. Layer by layer, their core samples went back more than 10,000 years -- allowing the scientists to see what happened both before and after the flood. By dating sediment layers as well as clam shells that were still closed shut (indicating that the animals were buried and preserved in the same place they lived), Giosan's group determined that the Black Sea was 30 meters (98 feet) below present its level at the time of the flood, not 80 meters (262 feet) as Ryan's team maintains. That suggests the flood was much smaller than originally thought. "It moves the balance of evidence from this being a big, catastrophic event to its not being such a big event," said oceanographer Mark Siddall, of the University of Bristol in the United Kingdom. Ryan remains skeptical about the new paper, which he said depended largely on analyses of just two mollusk shells that were completely destroyed by the work, leaving no opportunity for the results to be replicated. Giosan said he has invited Ryan to join him in an effort to replicate and extend the results by drilling more cores in the Danube delta. Now that the area is open for business, scientists hope that gaining a clearer picture of the Black Sea's past will help them get to the bottom of another important question: How much has climate change contributed to the region's history, and what does the future hold in store? Related Links: |
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