AME 17:37-47 (1999)  -  doi:10.3354/ame017037

Seasonal dynamics of cyst formation of pelagic strombidiid ciliates in a deep prealpine lake

Helga Müller*, Christine Wünsch

Limnological Institute, PO Box 5560, D-78434 Konstanz, Germany

ABSTRACT: Population dynamics of the oligotrich ciliates Limnostrombidium viride and Pelagostrombidium fallax were recorded in prealpine Lake Constance, Germany, from February through November 1997. Simultaneously, their flask-shaped resting cysts were collected in sediment traps. We describe for the first time the resting stages of L. viride. Motile stages and cysts of this species were restricted to April/May, with a maximum flux rate of 2 x 104 cysts m-2 d-1. Pelagostrombidium fallax, a dominant species throughout the year, encysted in March to June and September to November. Maximum flux rates of 1.8 x 105 and 2.1 x 105 cysts m-2 d-1 were observed in spring and autumn, respectively. Mean flux rates were 4 x 104 cysts m-2 d-1 in spring and 3 x 104 cysts m-2 d-1 in autumn. In summer, cyst formation ceased over a period when water temperatures were >18°C close to the lake surface. Encystment of P. fallax in spring was significantly negatively correlated with chlorophyll a.

KEY WORDS: Oligotrichida · Cyst · Limnostrombidium viride · Pelagostrombidium

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