Media Releases

Thursday, April 30, 2015 (Halifax, N.S.) — The fossils of marine species that went extinct over the last 23 million years are giving an international team of scientists insight into the species that are at risk today, as well as where hotspots of extinction may be located.

Dr. Heike Lotze and Dr. Derek Tittensor of Dalhousie’s Faculty of Science joined a international research team of ecologists and paleontologists to study fossil records from the past 23 million years—a period most closely resembling Earth today—and combined that data with what we know about the present state of our oceans. The study will be published in Science on May 1.

“Our idea was to map marine extinctions in a world with and without humans, in order to understand the baseline of extinction risk in the ocean,” said Lotze, a Canada Research Chair in Marine Renewable Resources and associate professor at Dalhousie. “Areas that have naturally high extinction risk may need extra management and conservation efforts, especially if they also face high pressure from human activities in today’s ocean.”

“Examining the fossil record can help identify the species that were particularly vulnerable to extinction,” explained Tittensor, an adjunct biology professor with Dalhousie and researcher with the United Nations Environment Programme World Conservation Monitoring Centre. “Patterns of extinction over the last 23 million years can then be used to help us understand the extinction risk we’re seeing in modern ocean ecosystems.”

According to the fossil record, sharks and corals tended to be more resilient species, while whales, dolphins and seals were more prone to extinction. Species with smaller geographic ranges were also more prone to extinction.

The ecologists in the group then used what they learned from the fossil record to determine which marine areas and species would be most at risk today, given the added threats from human activities and climate change. The rich biodiversity, high impact levels, and concentration of extinction-vulnerable species in areas like the Caribbean and Indo-Pacific, led to them being identified as extinction hotspots in the study.

“Historically, the species in these areas had higher natural extinction risks,” said Tittensor. “Today, they may be increasingly prone to accelerated extinction rates because of pressures like overfishing, pollution and climate change.”

Other co-authors are from; University of California in Berkley; University of Massachusetts in Boston; Mount Allison University in Sackville, New Brunswick; University of Oslo in Norway; College of William and Mary in Williamsburg, VA; University of Washington, Seattle; Smithsonian Tropical Research Institute in Panamá; and University of Queensland in St. Lucia, Australia.

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Janet Bryson
Senior Communications Advisor
Dalhousie University
(902) 494-1269
janet.bryson@dal.ca