BioProject

We present a method for reconstructing past cyanobacterial communities using a temporally high resolved genetic approach on sedimentary DNA (sedDNA) from two stratified peri-alpine lakes in Switzerland (Lake Greifensee and Lake Zurich). More...

We present a method for reconstructing past cyanobacterial communities using a temporally high resolved genetic approach on sedimentary DNA (sedDNA) from two stratified peri-alpine lakes in Switzerland (Lake Greifensee and Lake Zurich). We successfully sequenced a 400 nucleotides-long amplicon in the 16S rRNA gene using high-throughput sequencing. The amplicons were used to build a phylogeny summarizing the diversity over the past 200 years in the two lakes. Sequencing revealed a high diversity of cyanobacteria in both lakes. Operational taxonomic units (OTUs) spanned the whole phylum Cyanobacteria and included representatives of a newly described line of bacteria termed Malainabacteria which share common ancestry with cyanobacteria, and have not been previously reported in lakes. The sequencing data was validated using a dataset comprising of 40 years of pelagic phytoplankton microscopic identification from each lake. Common taxa identified in the pelagic samples were also recovered from the sediments. The linear model confirmed a strong and significant relationship (R2=0.86) between pelagic species richness estimated by microscopy and OTU richness from the sediments. The slope for each lake was close to the 1:1 line, but the diversity derived from the sedDNA had a higher baseline compared to microscopy. The water-sediments richness relationship differed among cyanobacterial orders, revealing that diversity of Chroococcales and Synechococcales was widely underestimated by microscopy. Our results demonstrate the feasibility of this approach for the reconstruction of past cyanobacterial pelagic communities using lake sedDNA, and its potential for exploring variation in phylogenetic diversity and community structure over long-term lake historical changes. Less...