The seasonal occurrence and depth zonation of radiolarians in Korsfjorden, Western Norway

Radiolarians with well developed skeleton from monthly plankton samples taken between November 1969 and May 1971 in Korsfjorden were studied. The taxonomy and vertical zonation of the five most common species: Echinomma leptodermum, Cromyechinus borealis, Lithomelissa setosa, Protocystis tridens, and Challengeron diodon are discussed. A native radiolarian fauna in Korsfjorden is augmented every spring by species introduced by the influx of Atlantic water. Diversity and redundancy values have been calculated and discussed. The maximum occurrence was in late summer and early autumn and has been tried correlated in time with maximum occurrence of other dominating plankton groups.