Photosynthetic algae and heterotrophic protozoa play a key role in many recent and paleo ecosystems and habitats. They comprise a wide range of phylogenetic diverse taxonomic groups, morphologies, and life forms, ranging from microscopic cells to kelps of oceans. Primary biodiversity data are used in environmental monitoring and in taxonomical, ecological, limnological, marine, and paleontological research. To reach all those user groups, our BioCASe portal aims at giving common access to all relevant data published in the Global Biodiversity Information Facility and to enrich those with additional information.