Polar Biology

, Volume 38, Issue 8, pp 1213–1222

Effects of sea-ice cover on marine benthic communities: a natural experiment in Commonwealth Bay, East Antarctica

  • Graeme F. Clark
  • Ezequiel M. Marzinelli
  • Christopher J. Fogwill
  • Chris S. M. Turney
  • Emma L. Johnston
Original Paper

DOI: 10.1007/s00300-015-1688-x

Cite this article as:
Clark, G.F., Marzinelli, E.M., Fogwill, C. et al. Polar Biol (2015) 38: 1213. doi:10.1007/s00300-015-1688-x

Abstract

Sea-ice is a key physical driver of Antarctic marine ecosystems. Understanding ecological effects of sea-ice is particularly important given current and future climate change, but a major obstacle is the impracticality of manipulating sea-ice at a relevant scale. However, large-scale anomalous events, such as those occurring in Commonwealth Bay, East Antarctica, provide opportunities for natural experiments. Historically, katabatic winds have kept Commonwealth Bay ice-free for most of each year, but since 2010, a massive grounded iceberg has resulted in year-round sea-ice cover. We surveyed benthic communities in Commonwealth Bay approximately 3 years after continuous sea-ice cover began and found algal bed communities in severe decline. The majority (~75 %) of large macroalgae were decomposing, and the remainder were discoloured or bleached, while approximately 40 % of encrusting coralline algae were bleached. Accompanying this, the presence of invertebrates such as ophiuroids and polychaetes suggests that communities are in the early stages of transitioning to an invertebrate-dominated state. With a known start date, monitoring benthic communities in Commonwealth Bay will allow quantification of rates of benthic regime shifts in response to sea-ice cover, and improve understanding of the vulnerability of polar ecosystems to climate change.

Keywords

AntarcticAustralasian Antarctic Expedition (AAE)BenthicIceberg B09BInvertebratesIrradianceLightMacroalgaePhase shiftRegime shift

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Graeme F. Clark
    • 1
  • Ezequiel M. Marzinelli
    • 1
    • 2
  • Christopher J. Fogwill
    • 1
  • Chris S. M. Turney
    • 1
  • Emma L. Johnston
    • 1
    • 2
  1. 1.Evolution and Ecology Research Centre, School of Biological, Earth and Environmental SciencesUniversity of New South WalesSydneyAustralia
  2. 2.Sydney Institute of Marine ScienceMosmanAustralia