The fluorescence in centrifuged sea water samples has been studied to find out the mechanism of the fluorescent dissolved organic matter origination. The centrifuging causes evolving of a large amount of the dissolved fluorescent matter in the form of several gravitational fractions with different spectra of the excitation and fluorescence. The excitation spectra of centrifuged seawater samples change depending on the depth and the season. The applied centrifuging method allowed proving the existence of excitation and fluorescence bands in the short-wave spectra of the seawater samples. It was established that some layers of organic suspension are formed in the photic sea zone, and their origination is connected with the seasonal bioproductivity.