Thilo Bauer, Michael Butkay, Ralf Fontes, Stephan Krall, Michael Müller, Sebastian Hess and Sergio A. Muñoz-Gómez

We report a citizen science project started in 2021, which brings together the work of amateur microscopists and academic research. First, we selected specific genera to be collected in nature and to be subjected to morphological, ecological and genetic analysis. The sampling sites include various ephemeral to permanent habitats such as puddles, swamps and ponds. Samples are collected from nature, isolated strains are cultivated, where possible. The morphological details of the ciliates found are documented by light microscopy, including diverse staining techniques and silver impregnation techniques. A new fluorescence double-staining technique using Ho342 and acridine orange was established. The double-staining technique can replace the traditional methyl green-pyronin staining in ciliate research. The technique enables live-cell imaging for longer time using a fluorescence microscope, as it does not harm the cells. Further fluorochromes were tested and applied to document morphology and inner cell organisation of the studied ciliates, e.g. the presence and distribution of phagosomes, acidic granules, acidosomes or mitochondria, and ciliary pattern. Genomic analysis will include short genomic sequence analysis for species determination as well as whole genomic analysis for selected isolated ciliate species.