A first documentation of Gloeotrichia pisum in Lake Kinneret: identification and characterization of a successful epiphytic colonial cyanobacterium

Abundant epiphytic colonies of the nostocalean cyanobacterium Gloeotrichia pisum Thuret ex Bornet & Flahault, 1886 were found for the first time in Lake Kinneret in August 2020, attached to inundated stems of the common reed, Phragmites australis. Here we report for the first time on the abundance and spatial distribution of the detected colonies, the morphological characteristics, as well as its characteristics pigments. We demonstrate that the colonies fix nitrogen and show the diazotropic community composition and phylogenetic relations. The genomic community composition of the colonies reveals that these colonies host a diverse microbial community of microalgae, cyanobacteria, bacteria, and archaea. This study is the first record of the genus in Israel, providing insight on the invasive nature of G. pisum, and the ecological implications of its appearance in a freshwater ecosystem.