PHOTOACOUSTIC SPECTRA AFFECTED BY FUEL-OIL IN THE CHLOROCOCCAL ALGA SCENEDESMUS-ARMATUS

Photoacoustic (PA) spectra of the green chlorococcal alga Scenedesmus armatus grown in batch. cultures with fuel oil have been examined. Con centration-dependent increase in PA-signals in the red chlorophyll and the blue carotenoid regions of the treated algae was observed, irresp ective of the culture time. The maxima in the differential PA-spectra after a short-term (3 h) effect of AFOE exhibit a drop of used energy yield absorbed and provided by light-harvesting pigments. These spectr a in relation to the long-term cultures additionally prove that quante s of energy transferred to the photosynthetic process are lowered. The PA signal ratios for 684, 484 and 434 nm of algae cultured with/witho ut fuel oil indicate that temporal changes in photoacoustic signals ar e correlated to the growth rate of the algae exposed. These ratios rea ched the maxima values in 7th (AFOE) and 9th (10 ppm) day of cultures. The phytotoxicity data (the growth of population, chlorophyll a and d ry matter content of cells) and PA spectra of algae cultured with AFOE are discussed.