Polar Biology

, Volume 32, Issue 1, pp 71–82

Do sulphuric acid and the brown alga Desmarestia viridis support community structure in Arctic kelp patches by altering grazing impact, distribution patterns, and behaviour of sea urchins?

  • Markus Molis
  • Hendrik Wessels
  • Wilhelm Hagen
  • Ulf Karsten
  • Christian Wiencke
Original Paper

DOI: 10.1007/s00300-008-0504-2

Cite this article as:
Molis, M., Wessels, H., Hagen, W. et al. Polar Biol (2009) 32: 71. doi:10.1007/s00300-008-0504-2

Abstract

Macrobenthic community structure and the distribution of the green sea urchin (Strongylocentrotus droebachiensis) were recorded inside and outside (=barrens) of kelp patches (Alaria esculenta) at Kongsfjordneset, Svalbard between August 2002 and October 2006. In manipulative field experiments, conducted at Kongsfjordneset, Svalbard in August 2002, the effect of the presence of the brown seaweed Desmarestia viridis on sea urchin distribution and kelp grazing was determined. Additionally, we studied the effect of sulphuric acid, which is produced and stored by D. viridis, on sea urchin movements in the laboratory at Ny-Ålesund, Svalbard, in May 2006. Sea urchin densities were two- to threefold lower in kelp patches than on barrens. The macrobenthic community inside kelp patches hosted 39% more species and was of different species composition than on barrens. Anchored pieces of the kelp A. esculenta were less consumed when surrounded by D. viridis than non-surrounded conspecifics. Changes in pH affected the behaviour of sea urchins. Exposing sea urchins to 500 μl seawater at pH 7.5 caused them to stop, while the exposure of as little as 25 μl at pH 1 caused sea urchins to move in the opposite direction. Acid-mediated escape responses in sea urchin behaviour suggest chemical protection by D. viridis as an additional mechanism to mechanical protection in the generation of kelp refuges. These results improve our understanding of how isolated kelp beds can persist over a wide range of environmental conditions, like wave-sheltered sites, and suggest that changes in community structure may be in part attributable to altered trophic interactions.

Keywords

Alaria esculenta Associative defense Desmarestia viridis Destructive grazing Kongsfjorden Plant–herbivore interactions Strongylocentrotus droebachiensis Svalbard 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Markus Molis
    • 1
  • Hendrik Wessels
    • 2
  • Wilhelm Hagen
    • 2
  • Ulf Karsten
    • 3
  • Christian Wiencke
    • 4
  1. 1.Section Seaweed Biology, Biologische Anstalt HelgolandAlfred-Wegener-Institute for Polar and Marine ResearchHelgolandGermany
  2. 2.Department of Marine ZoologyUniversity of BremenBremenGermany
  3. 3.Department of Applied Ecology, Institute of Biological SciencesUniversity of RostockRostockGermany
  4. 4.Section Seaweed BiologyAlfred-Wegener-Institute for Polar and Marine ResearchBremerhavenGermany

Personalised recommendations