In this study we considered the seasonal and spatial variability of the maximum specific rate of photosynthesis
(assimilation number, PB
m), which describes the photosynthetic abilities of marine phytoplankton. Based on ship
(in situ) data from the global database of the photosynthetic curve parameters (PANGAEA), the dependence
of PB
m on Sea Surface Temperature (SST) and chlorophyll-a concentration (Chl-a) in the surface layer (0-30
meters) for the period from 2002 to 2013 was analyzed. The strongest relationship between PB
m and SST (r=0.82,
p-level<0.01) was observed in winter (December), while in spring and summer (March-August) the relationship
was moderate (r=0.30, p-level<0.01), and there was no correlation between the parameters in fall. The relationship
between PB
m and Chl-a was strong only near the Grand Banks of Newfoundland (r=-0.61, p-level<0.01). We
revealed a connection between PB
m values with the growing season of marine phytoplankton and compared regional
features and the range of PB
m variability: during spring bloom PB
m values varied in a wide range, decreased over
the summer and reached their minimum in fall, the maximum values were observed in winter. In addition, wellknown algorithms of PB
m as a function of seawater temperature have been reviewed and validated: they showed
a significant correlation with in situ data (r=0.44-0.81 at p<0.01). Moreover, due to the necessary to take into
account the seasonal and regional variability of PB
m the new empirical algorithms were developed. These new
algorithms showed a better performance compared to the other algorithms.