Proceedings of the International Ocean Discovery Program, Volume 376: by Cornel E J de Ronde uow.edu.au - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from uow.edu.au Daily Mail and Mail on Sunday newspapers.
Something Wiped Out Nearly All Sharks 19 Million Years Ago, New Research Suggests
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A careful arrangement of shark scales, or dermal denticles. (Image: Leah Rubin)
Scientists have stumbled upon a previously unknown extinction event that decimated ocean shark populations 19 million years ago. The cause of this sudden die-off, in which global shark populations plummeted by 90%, is a complete mystery.
The previously unidentified extinction event, as described in a Science paper published today, was discovered by accident. Elizabeth Sibert, the first author of the study and a postdoctoral fellow from the Yale Institute for Biospheric Sciences at Yale University, detected evidence of the extinction event while studying fossilized fish teeth and shark scales. Sibert was seeking to learn more about these mysterious bits and pieces, collectively known as ichthyoliths, so she, along with co-author Leah Rubin, a student at the College of the Atlantic at the time of the research, embark
reconstructed from sub-ice shelf and offshore sediments
J.A. Smith; C.-D. Hillenbrand; C. Subt; B.E. Rosenheim; T. Frederichs .
Abstract:
Because ice shelves respond to climatic forcing over a range of time
scales, from years to millennia, an understanding of their long-term
history is critically needed for predicting their future evolution. We
present the first detailed reconstruction of the Larsen C Ice Shelf (LCIS),
eastern Antarctic Peninsula (AP), based on data from sediment cores
recovered from below and in front of the ice shelf. Sedimentologic and
chronologic information reveals that the grounding line (GL) of an expanded
AP ice sheet had started its retreat from the midshelf prior to 17.7 ± 0.53