Evaluation of primary production parameters in Lake Kinneret (Israel)

Summary

Complete ¹⁴C-profiles are laborious and time-consuming. They cannot be performed on a routine basis at several sampling stations simultaneously. Therefore simplified procedures have been attempted in Lake Kinneret, where weekly exposures were carried out from March, 1969, to September, 1970.

Application of Talling's photosynthetic model offers several opportunities to calculate areal assimilation rates, provided the phytoplankton is fairly uniformly distributed throughout the trophogenic layer. If so, only two parameters are needed: a certain depth of the photosynthetically most efficient component, I_mec, and the maximal assimilation rate, at optimal light intensity. In the Kinneret, the level of 15% of incident blue light (not the deeper penetrating green light) and the rate of a mixed sample, suspended at 50% of incident I_mec, were found to satisfy the model. In this way synoptical data could be obtained conveniently from up to 8 stations dispersed over the lake.

Validity tests of the simplified procedures are presented, and the limitations of the short-cut approach are discussed.