Atmospheric CO 2 Increase: A Potential for Primary Production Enhancement in Lake Kinneret

Due to precipitation reduction, nutrient inputs into Lake Kinneret through Jordan river discharge declined. Nitrogen (N) supply into the Kinneret ecosystem is mostly external and that of Phosphorus (P) is partly internal and dust deposition. Therefore, decline of N and slight elevation of P concentrations occurred in the Kinneret Epilimnion. As a result, suppression of Peridinium biomass and enhancement of Cyanophyta, Chlorophyta and Diatoms were recorded. The Peridinium decline caused Primary Production (PP) reduction and although increased later, it accompanied the nano-plankton elevation. It is suggested that the PP enhancement is partly due to the natural photosynthetic capacity of nano-plankton and partly to global increase of atmospheric concentration of CO2. The suggestion of atmospheric CO2 increase and consequently PP, was supported by the pH (and obviously Alkalinity) increase. The enhancement of CO2 diffusion was an incentive factor which enhanced PP capacity.