From the Surface Ocean to the Seafloor: Linking Modern and Paleo-Genetics at the Sabrina Coast, East Antarctica (IN2017_V01)
Metadatos
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American Geophysical Union
Date
2023-04Referencia bibliográfica
Armbrecht, L., Focardi, A., Lawler, K.-A., O’Brien, P., Leventer, A., Noble, T. L., et al. (2023). From the surface ocean to the seafloor: Linking modern and paleo-genetics at the Sabrina Coast, East Antarctica (IN2017_V01). Journal of Geophysical Research: Biogeosciences, 128, e2022JG007252. [https://doi.org/10.1029/2022JG007252]
Patrocinador
Australian Government's Australian Antarctic Science Grant Programs AAS 4419, DP170100557; Australian Research Council FL140100021; Australian Research Training Program (RTP) scholarship; AAS 4333; ARC DECRA DE210100929Résumé
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 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 is preserved in the
sediments, which are instead 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.