DNA- and RNA-based bacterial communities and geochemical zonation under changing sediment porewater dynamics on the Aldabra Atoll

Aldabra Atoll's pristine carbonate sediments reveal distinct bacterial community shifts driven by geochemical zonation, contradicting initial expectations. Research found that while diversity decreases with depth, the lagoon's bacterial composition transitions from Pseudomonas-dominated sand to a complex mix of sulfate reducers (e.g., Desulfovibrio), sulfur oxidizers (Arcobacteraceae), and photo(hetero)trophs (Cyanobacteria) in anaerobic mud. Unexpectedly, deeper sediments showed high abundances of Halomonas or Alphaproteobacteria, linked to increased salinity and organic matter complexity. The study used 16S rRNA gene and transcript analysis to differentiate between live and dead bacterial populations, providing insights into sediment porewater dynamics under changing conditions.

von Hoyningen-Huene, A. J. E., Schneider, D., Fussmann, D., Reimer, A., Arp, G., & Daniel, R. (2022). DNA- and RNA-based bacterial communities and geochemical zonation under changing sediment porewater dynamics on the Aldabra Atoll. Scientific Reports, 12(1). https://doi.org/10.1038/s41598-022-07980-0