On the quantitative characteristics of the pelagic ecosystem of Dalnee lake (Kamchatka)

The parameters of biomass and productivity of the main components of the pelagic ecosystem have been estimated in lake Dalnee (Kamchatka) during the first phase of the period of vegetation in July 1969. The water column in the lake during this period was stratified. The layer-character of vertical distribution of bacteria, phytoplankton, protozoa, rotifers and young stages of crustaceans was elucidated. The adult copepods migrate during the day. The nutrition of the mass species of zooplankton was studied using the C¹⁴-method. The data on the spectrum of feeding, on rations and on optimal food concentrations were ascertained. All these data, together with the observations in the lake, were used for the construction of a scheme of energy flow. The scheme shows that the ecosystem of the lake receives the third part of its energy from the land as allochtonous organic matter via microbial biosynthesis. The main part of energy accessible to the animals of the second trophical level is used by protozoa, and of a third part by the predatory rotiferAsplanchna.