Shifts in DNA yield and biological community composition in stored sediment: implications for paleogenomic studies

Lake sediments hold a wealth of information from past environments that is highly valuable for paleolimnological reconstructions. These studies increasingly apply modern molecular tools targeting sedimentary DNA (sedDNA). However, sediment core sampling can be logistically difficult, making immediate subsampling sedDNA challenging. Sediment cores are often refrigerated (4 °C) weeks or months before subsampling. We investigated the impact storage time on changes in (purified as cell lysate) concentrations and shifts biological communities following lake surface at 4 °C up to 24 weeks. samples (~ 0.22 g, triplicate per point) were spiked with purified (100 200 ng) lysate brackish water cyanobacterium produces cyanotoxin nodularin non-spiked. Samples analysed every 1–4 over 24-week period. Droplet digital PCR showed no significant decrease target gene ( synthetase – subunit F; ndaF ) period DNA, while copy number decreased by more than half lysate-spiked samples. There was change bacteria eukaryotic community composition assessed using metabarcoding. Amongst bacteria, cyanobacterial signal became negligible after 5 Proteobacteria increased. In community, Cercozoa dominant 6 data demonstrate yields shift significantly when stored chilled This highlights need rapid appropriate paleogenomic studies.