ANTARCTIC DISTRIBUTION, PIGMENT AND LIPID COMPOSITION, AND MOLECULAR IDENTIFICATION OF THE BRINE DINOFLAGELLATE POLARELLA GLACIALIS (DINOPHYCEAE)

Authors

  • Paul G. Thomson,

    1. Department of the Environment and Heritage, Australian Antarctic Division and the Antarctic Climate and Ecosystems CRC, Channel Highway, Kingston, Tasmania 7050, Australia
    Search for more papers by this author
  • Simon W. Wright,

    1. Department of the Environment and Heritage, Australian Antarctic Division and the Antarctic Climate and Ecosystems CRC, Channel Highway, Kingston, Tasmania 7050, Australia
    Search for more papers by this author
  • Christopher J. S. Bolch,

    1. School of Aquaculture, University of Tasmania, P.O. Box 1370, Launceston, Tasmania 7250, Australia
    Search for more papers by this author
  • Peter D. Nichols,

    1. CSIRO Marine Research and Antarctic Climate and Ecosystems CRC, P.O. Box 1538, Hobart, Tasmania 7001, Australia
    Search for more papers by this author
  • Jennifer H. Skerratt,

    1. CSIRO Marine Research and Antarctic Climate and Ecosystems CRC, P.O. Box 1538, Hobart, Tasmania 7001, Australia
    Search for more papers by this author
  • Andrew McMinn

    1. Institute of Antarctic and Southern Ocean Studies and the Antarctic Climate and Ecosystems CRC, University of Tasmania, P.O. Box 252–77, Hobart, Tasmania 7001, Australia
    Search for more papers by this author

  • 1 Received 16 September 2003. Accepted 22 June 2004.

Abstract

Polarella glacialis (Montresor et al.) was identified in Davis Station sea ice by morphological and DNA sequence comparison of cultures with those of the authentic strain P. glacialis CCMP 1383 isolated from McMurdo Sound. Cells and cysts of the Davis isolate (FL1B) were morphologically indistinguishable from P. glacialis, and comparison of the large subunit rDNA of both cultures demonstrated only 0.2% sequence divergence over 1366 base pairs. The photosynthetic pigments of P. glacialis (strains FL1B and CCMP 1383) were typical of dinoflagellates, with peridinin (contributing up to 31%) as the major accessory pigment. Extremely high levels of polyunsaturated fatty acids (PUFA, up to 76.3%) were characteristic of P. glacialis isolate FL1B. The high PUFA concentration of this species is thought to be an adaptation to survive the cold temperatures of the upper fast ice. The sterol profile of FL1B was atypical of dinoflagellates, with 4-desmethylsterols (up to 79%) in greater abundance than 4α-methyl sterols (up to 24%). 27-Nor-24-methylcholest-5,22E-dien-3β-ol was identified as the principle sterol in P. glacialis, contributing up to 64% of the total sterol composition.

Ancillary