title: Climate change and trophic response of the Antarctic bottom fauna.
abstract: BACKGROUND
  As Earth warms, temperate and subpolar marine species will increasingly shift their geographic ranges poleward. The endemic shelf fauna of Antarctica is especially vulnerable to climate-mediated biological invasions because cold temperatures currently exclude the durophagous (shell-breaking) predators that structure shallow-benthic communities elsewhere.
  
  
  RESULTS
  We used the Eocene fossil record from Seymour Island, Antarctic Peninsula, to project specifically how global warming will reorganize the nearshore benthos of Antarctica. A long-term cooling trend, which began with a sharp temperature drop approximately 41 Ma (million years ago), eliminated durophagous predators-teleosts (modern bony fish), decapod crustaceans (crabs and lobsters) and almost all neoselachian elasmobranchs (modern sharks and rays)-from Antarctic nearshore waters after the Eocene. Even prior to those extinctions, durophagous predators became less active as coastal sea temperatures declined from 41 Ma to the end of the Eocene, approximately 33.5 Ma. In response, dense populations of suspension-feeding ophiuroids and crinoids abruptly appeared. Dense aggregations of brachiopods transcended the cooling event with no apparent change in predation pressure, nor were there changes in the frequency of shell-drilling predation on venerid bivalves.
  
  
  CONCLUSIONS
  Rapid warming in the Southern Ocean is now removing the physiological barriers to shell-breaking predators, and crabs are returning to the Antarctic Peninsula. Over the coming decades to centuries, we predict a rapid reversal of the Eocene trends. Increasing predation will reduce or eliminate extant dense populations of suspension-feeding echinoderms from nearshore habitats along the Peninsula while brachiopods will continue to form large populations, and the intensity of shell-drilling predation on infaunal bivalves will not change appreciably. In time the ecological effects of global warming could spread to other portions of the Antarctic coast. The differential responses of faunal components will reduce the endemic character of Antarctic subtidal communities, homogenizing them with nearshore communities at lower latitudes.
authors.affiliation: Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida, United States of America. raronson@fit.edu
authors.forename: Richard B
authors.initials: RB
authors.lastname: Aronson
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Moody
authors.forename: Linda C
authors.initials: LC
authors.lastname: Ivany
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Blake
authors.forename: John E
authors.initials: JE
authors.lastname: Werner
authors.forename: Alexander
authors.initials: A
authors.lastname: Glass
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D044822:Biodiversity; D004447:Echinodermata / Q000502:physiology; D017753:Ecosystem; D053476:Extinction, Biological; D005580:Fossils; D005843:Geography; D017752:Greenhouse Effect; D049690:History, Ancient; D011235:Predatory Behavior; D025341:Principal Component Analysis; D013997:Time Factors