Antarctic Science



Evolution and diversity of the benthic fauna of the Southern Ocean continental shelf


ANDREW CLARKE a1c1, RICHARD B. ARONSON a2, J. ALISTAIR CRAME a1, JOSEP-MARIA GILI a3 and DANIEL B. BLAKE a4
a1 British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3 0ET, UK
a2 Dauphin Island Sea Lab, 101 Bienville Boulevard, Dauphin Island, AL 36528, USA
a3 Dept Biologia Marina, Institut de Ciències del Mar, CMIMA-CSIC, Passeig Maritim de la Barceloneta, 37-49, 08003 Barcelona, Spain
a4 Department of Geology, 1301 West Green Street, University of Illinois, Urbana, IL 61801, USA

Article author query
clarke a   [PubMed][Google Scholar] 
aronson rb   [PubMed][Google Scholar] 
crame ja   [PubMed][Google Scholar] 
gili jm   [PubMed][Google Scholar] 
blake db   [PubMed][Google Scholar] 

Abstract

The modern benthic fauna of the Antarctic continental shelf is characterized by the lack of active, skeleton-breaking (durophagous) predators such as crabs, lobsters and many fish, and the dominance in many areas of epifaunal suspension feeders. It has often been remarked that these ecological characteristics give the fauna a distinctly Palaeozoic feel, with the assumption that it may be an evolutionary relic. We now know that this is not so, and fossil evidence shows clearly that many of the taxa and life-styles that are absent now were previously present. The modern fauna has been shaped by a number of factors, important among which have been oceanographic changes and the onset of Cenozoic glaciation. Sea-water cooling, and periodic fragmentation of ranges and bathymetric shifts in distribution driven by variability in the size and extent of the continental ice cap on Milankovitch frequencies will all have caused both extinction and allopatric speciation. The modern glacial setting with relatively low terrestrial impact away from immediate coastal regions, and scouring by icebergs are the key factors influencing the ecology and population dynamics for the modern Antarctic benthos.

(Received February 5 2004)
(Accepted May 17 2004)


Key Words: climatic cooling; extinction; glaciations; Milankovitch; predation; speciation.

Correspondence:
c1 corresponding author: accl@bas.ac.uk


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