In April 2014, dual bloom of green algae and purple bacteria occurred in a shallow, alkaline soda pan (Kiskunság National Park, Hungary). The water was only 5 cm deep, in which an upper green layer was clearly separated from a near-sediment purple one. Based on microscopy and DNA-based identification, the upper was inhabited by a dense population of the planktonic green alga,
Oocystis submarina
Lagerheim, while the deeper layer was formed by purple, bacteriochlorophyll-containing bacteria, predominated by
Thiorhodospira
and
Rhodobaca
. Additional bacterial taxa with a presumed capability of anoxygenic phototrophic growth belonged to the genera
Loktanella
and
Porphyrobacter
. Comparing the bacterial community of the purple layer with a former blooming event in a nearby soda pan, similar functional but different taxonomic composition was revealed. Members from many dominant bacterial groups were successfully cultivated including potentially new species, which could be the result of the application of newly designed media.
Electronic supplementary material
The online version of this article (10.1007/s00792-019-01098-4) contains supplementary material, which is available to authorized users.