the maximum photosynthesis intensity (
) and the initial slope of light curves 
B were studied. Throughout the year, the values of the photosynthetic parameters varied within one order of magnitude, i.e.,
from 1 to 11 mgC mgChl
1 h
1 and 
from 0.04 to 0.20 mgC mgChl
1 h
1/(W m
2). The spatial and temporal variability of
and B were lower than that of the chlorophyll concentration. The seasonal dynamics of the 
val-ues is characterized by their growth from winter to summer and their decrease by the end of the year. The annual
changes in
are controlled by temperature, and they have a weak dependence on the phytoplankton adap-tation to incident solar radiation. The share of the temperature in the overall variability of
and Ik is 56
70%, and the temperature dependencies of these parameters are described by exponential functions. The temporal dynamics of
B are nitrate- and chlorophyll a-dependent. The temporal changes in the maximum quantum yield of phytoplankton photosynthesis (
max) calculated by B and the average specific light absorp-tion by algae in the photosynthetically active radiation range (
) were analyzed. It was shown that max and 
were chlorophyll concentration-dependent parameters, but their changes are in the opposite direction. The max values increase with a rise in the chlorophyll concentration, whereas the 
values decrease. Over a wide range of chlorophyll concentration values (from 0.1 to 20 mg/m3), the relationship between the
B values and the chlorophyll concentration can be approximated by a dome-shaped curve with a maximum at about 3 mg/m3.