Variations in dinoflagellate cyst morphology under conditions of changing salinity during the last 2000 years in the Limfjord, Denmark

Morphological variations are examined in the dinoflagellate cysts Spiniferi tes spp., Lingulodinium polyedrum and Protoceratium reticulatum (= Operculo dinium centrocarpum) from a core taken in the Bjornsholm Bay, the Limfjord, Denmark. The fjord has a history of changing salinity, and unusual cyst mo rphotypes are found in the greatest numbers during periods of inferred low salinity. Variation occurs primarily in cyst process morphology, and the ab errant morphotypes have processes that are shorter, thicker and/or more mem branous. The different morphotypes are described and compared with other va rieties and forms of the three taxa and to other closely related taxa. (C) 2000 Elsevier Science B.V. All rights reserved.