The influence of biotic factors on phytoplankton pigment composition and resources in Baltic ecosystems: new analytical results

Mathematical expressions were derived describing the distribution and concentration of individual phytoplankton pigments with respect to biotic factors in the southern Baltic. Relationships were established between the chlorophyll a concentration and the total phytoplankton biomass (represented by the organic carbon content), as well as between the concentration of marker pigments and the biomasses of the corresponding phytoplankton classes. Knowledge of chlorophyll a concentrations allows the phytoplankton biomass to be estimated with a precision characterised by relative statistical errors according to logarithmic statistics of sigma_ = ca 56%. The best approximation was obtained for the dependence of the Bacillariophyceae biomass on the fucoxanthin concentration (sigma_ = 60%), Chlorophyceae on the lutein concentration (sigma_ = 48%), and the total biomass of Dinophyceae,Bacillariophyceae and Euglenophyceae on the concentration of diadinoxanthin, the main carotenoid pigment present in cells of species from these classes (sigma_ = 60%).