A database on photoprotective compounds in cyanobacteria, phytoplankton and macroalgae has been developed. It contains information on photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin and other not yet identified compounds reported in aquatic organisms, their habitat, the collection site and date and the reference. Further information on the absorption maxima and extinction coefficients of different photoprotective compounds as well as experimental procedures are provided (see http://www.biologie.uni-erlangen:de/botanik1/index.html). The database answers the urgent need for a library on these substances and provides scientists in the field with the necessary information to identify and quantify screening pigments in different aquatic organisms from various growing sites and different collection dates. (C) 2000 Elsevier Science B.V. All rights reserved.