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

Antarctic Australasian Antarctic Expedition (AAE) Benthic Iceberg B09B Invertebrates Irradiance Light Macroalgae Phase shift Regime 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

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