The LakePulse Metagenome-Assembled Genome catalogue

Lakes are heterogenous ecosystems inhabited by a rich microbiome whose
genomic diversity is poorly defined. We present a continental-scale study
of metagenomes representing 6.5-million km2 of the most lake-rich
landscape on Earth. Analysis of 308 Canadian lakes resulted in a
metagenome-assembled genome (MAG) catalogue of 1,008 mostly novel
bacterial genomospecies. Lake trophic state was a leading driver of
taxonomic and functional diversity among MAG assemblages, reflecting the
responses of communities profiled by 16S rRNA amplicons and gene-centric
metagenomics. Coupling the MAG catalogue with watershed geomatics revealed
terrestrial influences of soils and land use on assemblages. Agriculture
and human population density were drivers of turnover, indicating
detectable anthropogenic imprints on lake bacteria at the continental
scale. The sensitivity of bacterial assemblages to human impact reinforces
lakes as sentinels of environmental change. Overall, the LakePulse MAG
catalogue greatly expands the freshwater genomic landscape, advancing an
integrative view of diversity across Earth's microbiomes.