Contrasting patterns of freshwater microbial metabolic potentials and functional gene interactions between an acidic mining lake and a weakly alkaline lake

Abstract

AbstractAcidic coal mining lakes (AMLs) are characterized by low pH, low biodiversity, and high concentrations of sulfate and metals. However, to date, knowledge is inadequate on the involvement of the aquatic microbial functions in biogeochemical processes of an AML. Here, we use a natural weakly alkaline lake (WAL) as a reference to investigate the functional gene structure of microbial communities in the aerobic surface waters of an AML by using a metagenomic approach with GeoChip‐based functional gene arrays (GeoChip 5.0). We found significant differences in the compositions of the microbial functional genes between the two lake types. The AML had significantly lower gene diversity than the WAL, and the functional genes detected in the AML were almost a subset of those in the WAL. We also found significant differences in the microbial metabolic potentials between the two lake types. In the AML, the microbial communities had higher functional capacities in phosphorus‐utilization, sulfur oxidation, and metal‐detoxification and had lower metabolic potentials of carbon and nitrogen fixation, and the degradation of starch, hemicellulose, cellulose, chitin, and lignin than those in the WAL. By performing null model and network analyses, we observed stronger deterministic effects of the functional gene assemblages and greater clustering among the co‐occurring functional genes in the AML than those in the WAL. Altogether, we demonstrated contrasting patterns of freshwater microbial metabolic potentials and functional gene interactions between an AML and a WAL, which may advance the understanding of microbial functional response to acidification in freshwater lakes.