Past cyanobacterial biodiversity in polar regions

Looking to the past, the FNRS project HERBA aims to study the past diversity and biogeography of cyanobacteria in polar regions by investigating herbaria specimens from the Smithsonian Institution (Washington, DC, USA). First results, obtained with 454 pyrosequencing of the 16S rRNA gene V3-V4 segment, showed that it was possible to retrieve the sequences of Antarctic samples taken in 1948-9 from Ross Island, in 1940 from Deception Island and in 1964 from Victoria Land. DNA could be amplified in all cases and 55 OTUs (97.5% similarity) were detected. Sequences of Nostoc sp., Microcoleus sp., Phormidesmis priestleyi, Leptolyngbya sp., and Timaviella sp. were retrieved and compared with present-day sequences. This study gives access to the cyanobacterial community composition in a period where anthropogenic and climatic pressures were still low in the remote polar regions and will allow to detect possible changes in biogeographic patterns or shifts of genotypes towards more generalist ones.