FN Archimer Export Format
PT J
TI Stress factors resulting from the Arctic vernal sea-ice melt : Impact on the viability of bacterial communities associated with sympagic algae
BT 
AF Amiraux, Rémi
   Burot, Christopher
   Bonin, Patricia
   Massé, Guillaume
   Guasco, Sophie
   Babin, Marcel
   Vaultier, Frédéric
   Rontani, Jean-François
AS 1:1,2,3;2:1;3:1;4:3;5:1;6:3;7:1;8:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 Aix-Marseille University, Université de Toulon, CNRS/INSU/IRD, Mediterranean Institute of Oceanography (MIO), Marseille, France
   UMR 6539 Laboratoire des Sciences de l’Environnement Marin (CNRS, UBO, IRD, Ifremer) Institut Universitaire Européen de la Mer (IUEM) Plouzané, France
   Takuvik Joint International Laboratory, Laval University (Canada)—CNRS, Département de Biologie, Université Laval, Québec, Canada
C2 UNIV AIX MARSEILLE, FRANCE
   UBO, FRANCE
   UNIV LAVAL, CANADA
UM LEMAR
IN WOS Cotutelle UMR
   DOAJ
   copubli-france
   copubli-univ-france
   copubli-int-hors-europe
IF 6.053
TC 7
UR https://archimer.ifremer.fr/doc/00681/79329/81840.pdf
LA English
DT Article
DE ;Bacteria;Sea ice;Sympagic algae;Ice biota;Viability;Stress factors;Salinity;Bactericidal free fatty acids;Carbon export
AB During sea-ice melt in the Arctic, primary production by sympagic (sea-ice) algae can be exported efficiently to the seabed if sinking rates are rapid and activities of associated heterotrophic bacteria are limited. Salinity stress due to melting ice has been suggested to account for such low bacterial activity. We further tested this hypothesis by analyzing samples of sea ice and sinking particles collected from May 18 to June 29, 2016, in western Baffin Bay as part of the Green Edge project. We applied a method not previously used in polar regions—quantitative PCR coupled to the propidium monoazide DNA-binding method—to evaluate the viability of bacteria associated with sympagic and sinking algae. We also measured cis-trans isomerase activity, known to indicate rapid bacterial response to salinity stress in culture studies, as well as free fatty acids known to be produced by algae as bactericidal compounds. The viability of sympagic-associated bacteria was strong in May (only approximately 10% mortality of total bacteria) and weaker in June (average mortality of 43%; maximum of 75%), with instances of elevated mortality in sinking particle samples across the time series (up to 72%). Short-term stress reflected by cis-trans isomerase activity was observed only in samples of sinking particles collected early in the time series. Following snow melt, however, and saturating levels of photosynthetically active radiation in June, we observed enhanced ice-algal production of bactericidal compounds (free palmitoleic acid; up to 4.8 mg L–1). We thus suggest that protection of sinking sympagic material from bacterial degradation early in a melt season results from low bacterial activity due to salinity stress, while later in the season, algal production of bactericidal compounds induces bacterial mortality. A succession of bacterial stressors during Arctic ice melt helps to explain the efficient export of sea-ice algal material to the seabed. 
PY 2020
SO Elementa-science Of The Anthropocene
SN 2325-1026
PU University of California Press
VL 8
IS 1
UT 000615210600018
DI 10.1525/elementa.076
ID 79329
ER

EF