During the spring seasons of 1983, 1986 and 1987 the development of phytoplankton in Lake
Zürich was investigated (from February to May) using samples taken at short term intervals. The
aim was to describe the effects of the short term dynamics of environmental factors on the algal
growth. The results could then be used to discuss the existing theories to assess the start of phytoplankton
growth pulses in spring.