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SUMMARY:The evolution of sea floor ecology in the Cenozoic of Antarctica -
  Dr Rowan Whittle - British Antarctic Survey\, Cambridge
DTSTART:20200313T162500Z
DTEND:20200313T170000Z
UID:TALK139117@talks.cam.ac.uk
CONTACT:Natalie Forrest
DESCRIPTION:Assessing changes in the ecology of fossil communities\, and h
 ow this affected the evolution of marine life\, gives insight into how mod
 ern communities will react to environmental change. Modern Antarctic sea f
 loor invertebrate marine communities are described as archaic and retrogra
 de\, dominated by surface living suspension feeding organisms. Previous st
 udies suggested this evolved in the Eocene\, with cooling decreasing shell
  crushing predation. However\, some recent evidence does not corroborate t
 his hypothesis. Looking back to the start of the Cenozoic\, the Cretaceous
 -Paleogene mass extinction did not cause a distinct change in Antarctic be
 nthic community ecology\, although the effects of the extinction in terms 
 of species loss was comparable with other areas globally. Other global sig
 nals at this time\, for example a shift in dominance between bivalves and 
 gastropods\, do occur in the Paleocene of Antarctica. During the Eocene\, 
 there was a radiation of many taxa. Stalked crinoids\, the main evidence f
 or the original hypothesis that Antarctic community structure arising at t
 his time\, are present. However\, we have linked this to asynchronous timi
 ng of the Marine Mesozoic Revolution in the Southern Hemisphere. Evidence 
 of the first glaciations in the west Antarctica comes from King George Isl
 and (South Shetland Islands). The Polonez Cove and Cape Melville Formation
 s preserve marine sedimentary sequences from the Oligocene and Miocene. Dr
 opstones\, diamictites and striated rocks confirm deposition in a glacial 
 environment. Both preserve abundant fossils\, representing Antarctica’s 
 first glacial sea floor communities. However\, the youngest unit\, does no
 t preserve an invertebrate community with the modern Antarctic ecological 
 structure. It is dominated by burrowing bivalves\, with a significant prop
 ortion of shell crushing decapods. Overall the ecology of Antarctic taxa h
 as links to climatic change\, but the story is much more complex than prev
 iously thought\, with links to predator and prey relationships and deposit
 ional environment. \n\n_Dr Rowan Whittle is a palaeobiologist at the Briti
 sh Antarctic Survey\, Cambridge._\n \n\n_Her research aims to answer the q
 uestion 'How did Antarctic sea floor ecology evolve?'  Her studies have fo
 cussed on the effects of global events such as the Cretaceous- Paleogene (
 K-Pg) mass extinction on invertebrate communities\, as well as tracing the
  fossil record of Antarctic invertebrates through time. Rowan has spent ti
 me collecting geological and biological samples in Antarctica to address t
 hese questions._ 
LOCATION:Tilley Lecture Theatre\, Department of Earth Sciences\, Downing S
 treet
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