Publication
From the Surface Ocean to the Seafloor: Linking Modern and Paleo-Genetics at the Sabrina Coast, East Antarctica (IN2017_V01)
Publisher:
American Geophysical Union (AGU)
Date:
04-2023
DOI:
10.1029/2022JG007252
Abstract: 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 ersity 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 licon sequencing (modern DNA) and shotgun metagenomics (sedimentary ancient DNA, sed aDNA). 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 sed aDNA is preserved in the sediments, which are instead dominated by Proteobacteria and Retaria. We compare the diatom microfossil and sed aDNA record and link the weak preservation of diatom sed aDNA 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.
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