Temperature, length and width of Tuberculodinium vancampoae (the resting cyst of Pyrophacus steinii) from surface sediments in the Omura Bay

Cyst forming dinoflagellates are useful in reconstructing past environments. For accuracy it is essential to know how environmental parameters such as salinity, temperature and light influence dinoflagellate cyst production and morphology. Here the effect of variation in these parameters on production and morphology of Tuberculodinium vancampoae (the resting stage of Pyrophacus steinii) is detailed. Encystment of T. vancampoae has been observed in all studied culture-experiments although only a few cysts are being formed at the limits of the temperature and salinity ranges (16.5°C, 34.8 °C and 20, 45 psu) with highest cyst production at 27 °C and 35 psu. Temperature clearly affects cyst morphology; cysts formed in cultures grown at 16.5 °C and 34.8 °C possess small, flattened processes. These cysts are not completely absent in cultures grown at intermediate temperatures but form only a minor part of the association.