Zooplankton respiration and its relation to plankton dynamics in two lakes of contrasting trophic state1

Abstract

The seasonal cycles of respiration of net zooplankton and microplankton were determined for euphotic zones of Lake Washington and Findley Lake. In Lake Washington net zooplankton respiration rates estimated from ETS activity ranged from 22.4 to 1,194 mg O·m−2·d−1 with the maximum occurring during the spring bloom. Net zooplankton respiration rates in Findley Lake ranged from 27 mg O·m−2·d−1 under ice cover to a maximum of 205 mg O·m−2·d−1, which occurred well after the bloom. Respiration rates estimated from ETS activity agreed well with those estimated from zooplankton species abundance. Zooplankton community respiration never exceeded 60% of primary production in Lake Washington; however, in Findley Lake zooplankton community respiration rates exceeded primary production during the latter part of the ice‐free growing season. Phosphorus regeneration rates calculated from zooplankton respiration appeared sufficient to supply most of the phytoplankton phosphorus requirement during summer stratification in Lake Washington.