Distribution and adaptations of sea ice inhabiting Harpacticoida (Crustacea, Copepoda) of the Weddell Sea (Antarctica)

• Main Authors: Dahms, H.-U., Bergmans, M., Schminke, H.K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 1990
• Subjects: Biogeography; Dormancy; Ecology; Life history; Salinity tolerance; Harpacticoida; PSW; Weddell Sea; Antarctic; Weddell; Antarc*; Antarctica; Sea ice
• Online Access: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3067

Seven harpacticoid species were found to be associated with sea ice collected during 5 Antarctic cruises of the RV Polarstern . Their distribution within the fast ice and pack ice zones of the Weddell Sea is presented. Whereas some individuals probably become entrapped into the ice only accidentally, at least 4 species are genuinely sympagic. These have evolved remarkable adaptations, as evidenced by field and laboratory studies of Drescheriella glacialis , which is by far the most abundant. Such adaptations include: the ability to penetrate deep into ice; a comparatively high salinity tolerance allowing it to endure large salinity fluctuations associated with ice crystal formation and melting; good swimming ability, necessary both for horizontal dispersal and for a planktonic intermezzo after annual melting of the sea ice. D. glacialis is the first polar non-vertebrate metazoan to be cultivated through its entire life cycle. Its life history suggests an r-strategy; this would be the first indication of such a trait in the polar environment. A new species of Drescheriella , on the other hand, exhibits resting stages (CIV-V) known to date only for Calanoida but not reported for Harpacticoida .