HETEROCAPSA ARCTICA SUBSP. FRIGIDA SUBSP. NOV. (PERIDINIALES, DINOPHYCEAE)—DESCRIPTION OF A NEW DINOFLAGELLATE AND ITS OCCURRENCE IN THE BALTIC SEA

Authors

  • Janne-Markus Rintala,

    1. Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland
      Finnish Institute of Marine Research, Erik Palménin aukio 1, P.O. Box 2, FI-00560 Helsinki, Finland
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    • Author for correspondence: e-mail janne-markus.rintala@ymparisto.fi.

    • Present addresses: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland; and Marine Research Centre, Finnish Environment Institute, Erik Palménin aukio 1, P.O. Box 140, FI-00251 Helsinki, Finland.

  • Heidi Hällfors,

    1. Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland
      Finnish Institute of Marine Research, Erik Palménin aukio 1, P.O. Box 2, FI-00560 Helsinki, Finland
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    • Present addresses: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland; and Marine Research Centre, Finnish Environment Institute, Erik Palménin aukio 1, P.O. Box 140, FI-00251 Helsinki, Finland.

  • Seija Hällfors,

    1. Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland
      Finnish Institute of Marine Research, Erik Palménin aukio 1, P.O. Box 2, FI-00560 Helsinki, Finland
    Search for more papers by this author
    • Present addresses: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland; and Marine Research Centre, Finnish Environment Institute, Erik Palménin aukio 1, P.O. Box 140, FI-00251 Helsinki, Finland.

  • Guy Hällfors,

    1. Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland
      Finnish Institute of Marine Research, Erik Palménin aukio 1, P.O. Box 2, FI-00560 Helsinki, Finland
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    • Present address: Haltiantie 8 C 20, FI-01600 Vantaa, Finland.

  • Markus Majaneva,

    1. Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland
      Finnish Institute of Marine Research, Erik Palménin aukio 1, P.O. Box 2, FI-00560 Helsinki, Finland
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    • Present addresses: Tvärminne Zoological Station, University of Helsinki, J.A. Palménin tie 260, FI-10900 Hanko, Finland; and Marine Research Centre, Finnish Environment Institute, Erik Palménin aukio 1, P.O. Box 140, FI-00251 Helsinki, Finland.

  • Jaanika Blomster

    1. Department of Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014 University of Helsinki, Finland
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  • Received 21 April 2009. Accepted 28 January 2010.

Abstract

Characteristics important in identification of Heterocapsa species (i.e., thecal plate pattern, body scale structure, and shape and position of the nucleus and pyrenoid) are practically identical in the dinoflagellate investigated here and in Heterocapsa arctica T. Horig. described from the Canadian Arctic. Analysis of internal transcribed spacer (ITS) sequences confirms that the two dinoflagellates are very closely related; however, there is a clear difference in their size and shape. Our experiments show that the low-salinity Baltic Sea brackish water does not reduce the size of the marine H. arctica to match that of the Baltic Sea morphotype. On the basis of these dissimilarities in general morphology and its geographic isolation in the Baltic Sea, we consider our material sufficiently differentiated from the typical H. arctica to warrant the status of a new subspecies, H. arctica subsp. frigida subsp. nov. Being of a distinct cell shape, the occurrence of subsp. frigida has been recorded in Algaline phytoplankton monitoring data collected since 1993. Although it has never been responsible for high biomass blooms, it commonly occurs in spring in the Northern Baltic Proper and in the western Gulf of Finland, when the water temperatures are <5°C.

Ancillary