Bacterial and Eukaryote communities in particulate organic matter of a meromictic mine pit lake

This study provides novel insights into the basal microbial resource communities and the resulting dietaryniche of a keystone grazer, Daphnia pulex, in a meromictic mining lake, revealing how environmentalgradients influence its food resources and primary carbon sources. Based on 16S/18S rRNA genesequencing, we observed that although the diversity of food resources available to Daphniapulex remained relatively constant with depth, variations in microbial community composition and in the13C and 15N isotopic signatures of particulate organic matter (POM) along the water column indicated ashift from surface-derived photosynthetic carbon to deeper, microbially reworked carbon sources.