File contains experimental data from the microcosm experiment, namely: flask ID, author initials, date, initial microcosm richness (species), initial microcosm richness (groups), presence dummies for all 8 species, total biovolume, cell counts for each of the 5 groups, temperature before exposure (TB), minimum, maximum, standard deviation (sd) of TB within Petri dish, time of measurement of TB, temperature after exposure to light (TA), minimum, maximum, sd of TA, time of measure of TA, temperature difference (TA-TB), mean, sd, minimum, maximum RGB, "second batch" dummy, time trend for the first batch, time (in hours, minutes), time trend of the second batch, dummy for the presence of the IG (isomorphic group), complementarity and sampling effects (and intermediary calculations) within each microcosm. Volumes are in 10e-6 m3, temperatures in °C.