Distribution of the Palynomorph Group: Phytoplankton Subgroup, Marine Dinoflagellate Cysts (Dinocysts)

Abstract

There is no simple relationship between cyst abundance and dinoflagellate primary productivity (Wall et al., 1977, p. 173). This is partly because the cyst-forming taxa and individuals are a small and inconsistent proportion of both the dinoflagellate and the total phytoplankton population (section 9.2), and partly because their distribution is modified by sedimentological and hydrographic factors. Once produced, the hydrodynamic behaviour of dinocysts is similar to that of other small sedimentary particles; most are medium to coarse silt-sized (16–62 (µm), but behave like fine silt or clay (≤ 15 µm) and thus become selectively concentrated in finegrained sediments (McKee et al., 1959, p. 540; Rossignol, 1969, p. 143; Davey, 1970, p. 342; Wall, 1971, p. 401; Dale, 1976; Rogers and Bremner, 1991, p. 64). Within the same general region where the motile phase forms blooms, hydrographic and sedimentary processes commonly lead to the corresponding cysts being selectively deposited in areas of fine-grained sediment termed ‘seed beds’ (≤ 2000 km⁻²; White and Lewis, 1982, p. 1186).