Cysts and Sediments: Gonyaulax Polyedra (Lingulodinium Machaerophorum) in Loch Creran

Abstract

The distribution of dinoflagellate cysts in sediments is a subject of increasing interest. There have been several approaches, of which two are relevant to this investigation. The studies of palynologists who endeavour to relate the distribution of cyst assemblages to environmental factors (for example Reid, 1972; Wall et al. 1977; Harland, 1983) and the studies of phycologists, concerned with toxic dinoflagellate blooms, who concentrate on the distributions of cysts of bloom species (for example Anderson, Kulis et al. 1982; Thayer et al. 1983). Consequently an increasing amount of information on quantitative distribution of cysts has become available. In 1976 Dale reported the investigation of sediments from Trondheimsfjord, relating the abundance of cysts to the percentage abundance of finer sediment. Wall et al. (1977) provided a more comprehensive picture of this relationship showing that cyst density (numbers of cysts per gram dry weight of sediment) increased logarithmically with increased percentage of the silt plus clay mineral fraction to a level where this comprised 50–60% of the sediment, after this no further increase occurred.