From the Surface Ocean to the Seafloor: Linking Modern and Paleo-Genetics at the Sabrina Coast, East Antarctica (IN2017_V01)
- 1Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia (linda.armbrecht@utas.edu.au)
- 2Australian Centre for Excellence in Antarctic Science (ACEAS)
- 3Climate Change Cluster, University of Technology Sydney, Sydney, Australia
- 4Research School of Earth Sciences, Australian National University, Acton, Australia
- 5Department of Geology, Colgate University, Hamilton, USA
- 6Department of Geology, University of Otago, Dunedin, New Zealand
- 7Department of Earth and Ocean Dynamics, University of Barcelona, Barcelona, Spain
- 8School of Natural Sciences, Macquarie University, Sydney, Australia
- 9Department of Stratigraphy and Paleontology, University of Granada, Granada, Spain
- 10Marine and Antarctic Geoscience, Geoscience Australia, Symonston, Australia
- 11Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
With ongoing climate change, research into the biological changes occurring in particularly vulnerable ecosystems, such as Antarctica, is critical. The Totten Glacier region, Sabrina Coast, is currently experiencing some of the highest rates of thinning across all East Antarctica. An assessment of the microscopic organisms supporting the ecosystem of the marginal sea-ice zone over the continental rise is important, yet there is a lack of knowledge about the diversity and distribution of these organisms throughout the water column, and their occurrence and/or preservation in the underlying sediments. Here, we provide a taxonomic overview of the modern and ancient marine bacterial and eukaryotic communities of the Totten Glacier region, using a combination of 16S and 18S rRNA gene amplicon sequencing (modern DNA) and shotgun metagenomics (sedimentary ancient DNA, sedaDNA). Our data show considerable differences between eukaryote and bacterial signals in the water column versus the sediments. Proteobacteria and diatoms dominate the bacterial and eukaryote composition in the upper water column, while diatoms, dinoflagellates, and haptophytes notably decrease in relative abundance with increasing water depth. Little diatom sedaDNA was recovered from the sediments. Instead, sedaDNA was dominated by Proteobacteria and Retaria. We compare the diatom microfossil and sedaDNA record and link the weak preservation of diatom sedaDNA to DNA degradation while sinking through the water column to the seafloor. This study provides the first assessment of DNA transfer from ocean waters to sediments and an overview of the microscopic communities occurring in the climatically important Totten Glacier region. Such knowledge is important when reconstructing past ecosystems using the emerging sedaDNA approach as a new paleo-proxy, and the interpretation of biological changes in response to Antarctic ice sheet advances and retreats.
How to cite: Armbrecht, L., Focardi, A., Lawler, K.-A., O’Brien, P., Leventer, A., Noble, T., Opdyke, B., Duffy, M., Evangelinos, D., George, S. C., Lieser, J., López-Quirós, A., Post, A., Ostrowski, M., Paulsen, I., and Armand, L.: From the Surface Ocean to the Seafloor: Linking Modern and Paleo-Genetics at the Sabrina Coast, East Antarctica (IN2017_V01), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13090, https://doi.org/10.5194/egusphere-egu24-13090, 2024.
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