SPECTROFLUOROMETRIC APPLICATIONS IN STUDYING MACROALGAL EXUDATES

In this paper we present a one-year investigation on the fluorescence characteristics of released products of selected Adriatic seaweeds. Th e technique chosen was W-fluorescence spectroscopy with the synchronou s mode, which involves the stepping of the excitation and emission mon ochromators. The five species of representative macrophytes, Cystoseir a compressa, Dictyopteris polypodioides, Gracilaria bursapastoris, Pte rocladia capillacea, and Ulva rigida, were chosen on the basis of thei r dominance in the plant communities typical for the area near Split - Central Adriatic. Our results suggest that macroalgal-related dissolv ed fluorescent matter can be categorized into two distinct groups of f luorescing compounds with the following excitation wavelengths: one fr om 320-360 nm, probably for compounds with 2 fused aromatic rings, and another from 360-420 nm, corresponding with 3 & 4 fused rings. The co ntribution of aromatics with 2 and with 3 & 4 rings was very similar i n the brown algae Cystoseira compressa and Dictyopteris polypodioides, while in the red algae Gracilaria bursapastoris and Pterocladia capil lacea as well in the green alga Ulva rigida the group with 2 rings dom inated.