The finite nature of fossil energy supply constrain the human community to tap new or not used primary energy resources beside increased efforts for an efficient use of energy. The exploitation of energy out of herbal biomass migth be such a potential source for primary energy. Because of a competition between "energy plants" and plants for food production on cultivable land the use of aquatic photoautotroph organisms ("algae") can be an interesting alternative solution.
In aquatic environments existing different conditions of limitation and photosynthetic apparatus than in terrestrial ecosystems. Because of this an estimation of expected yields can not be done by approximate values used in agriculture.
So it was necessary to investigate the full spectrum of strategies for ligth acclimitation in order to estimate the photosynthetic capacity in aquatic environments basicly. Another important thing was to consider the influence of epiphytes and other surface depositions on the photosynthetic effort. In terrestrial areas both phenomena just play a minor role because of a low atmospheric nutrient content.