Use of Stress Signals of Their Attached Bacteria to Monitor Sympagic Algae Preservation in Canadian Arctic Sediments

International audience Based on the strong aggregation of sympagic (ice-associated) algae and the high mortality or inactivity of bacteria attached to them, it was previously hypothesized that sympagic algae should be significant contributors to the export of carbon to Arctic sediments. In the prese...

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Bibliographic Details
Published in:Microorganisms
Main Authors: Amiraux, Rémi, Bonin, Patricia, Christopher, Burot, Rontani, Jean-Francois
Other Authors: Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2021
Subjects:
sympagic algae
Arctic
bacterial stress
lipid tracers
sediments
preservation
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
Global warming
Sea ice
Online Access:https://hal.science/hal-03525505
https://hal.science/hal-03525505/document
https://hal.science/hal-03525505/file/manuscript.v8.pdf
https://doi.org/10.3390/microorganisms9122626
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Summary:International audience Based on the strong aggregation of sympagic (ice-associated) algae and the high mortality or inactivity of bacteria attached to them, it was previously hypothesized that sympagic algae should be significant contributors to the export of carbon to Arctic sediments. In the present work, the lipid content of 30 sediment samples collected in the Canadian Arctic was investigated to test this hypothesis. The detection of high proportions of trans vaccenic fatty acid (resulting from cis-trans isomerase (CTI) activity of bacteria under hypersaline conditions) and 10S-hydroxyhexadec-8(trans)-enoic acid (resulting from 10S-DOX bacterial detoxification activity in the presence of deleterious free palmitoleic acid) confirmed: (i) the strong contribution of sympagic material to some Arctic sediments, and (ii) the impaired physiological status of its associated bacterial communities. Unlike terrestrial material, sympagic algae that had escaped zooplanktonic grazing appeared relatively preserved from biotic degradation in Arctic sediments. The expected reduction in sea ice cover resulting from global warming should cause a shift in the relative contributions of ice-associated vs. pelagic algae to the seafloor, and thus to a strong modification of the carbon cycle.

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