FN Archimer Export Format
PT J
TI Assessing the contribution of diazotrophs to microbial Fe uptake using a group specific approach in the Western Tropical South Pacific Ocean
BT 
AF Lory, C.
   Van Wambeke, F.
   Fourquez, M.
   Barani, A.
   Guieu, C.
   Tilliette, C.
   Marie, D.
   Nunige, S.
   Berman-Frank, I.
   Bonnet, Sophie
AS 1:1;2:1;3:1;4:1;5:2;6:2;7:3;8:1;9:4;10:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;
C1 Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO, Marseille, France
   Sorbonne Université, CNRS, Laboratoire d’Océanographie de Villefranche, LOV, F-06230, Villefranche-sur-Mer, France
   Sorbonne Université, CNRS, Station Biologique de Roscoff, Roscoff, France
   Department of Marine Biology, The Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
C2 UNIV AIX MARSEILLE, FRANCE
   UNIV SORBONNE, FRANCE
   UNIV SORBONNE, FRANCE
   UNIV HAIFA, ISRAEL
TC 9
UR https://archimer.ifremer.fr/doc/00768/87958/93591.pdf
   https://archimer.ifremer.fr/doc/00768/87958/93592.docx
LA English
DT Article
CR OUTPACE
   TONGA 2019
BO L'Atalante
AB Diazotrophs are often limited by iron (Fe) availability in the oligotrophic ocean. The Western Tropical South Pacific (WTSP) ocean has been suggested as an intense N2 fixation area due to Fe fertilizations through shallow hydrothermal activity. Yet, the Fe demand of diazotrophs in their natural habitat, where they cohabit with other microbial organisms also requiring Fe, remains unknown. Here we develop and apply a method consisting of coupling 55Fe uptake experiments with cell-sorting by flow cytometry, and provide group-specific rates of in situ Fe uptake by the microbial community in the WTSP, in addition to bulk and size fractionation rates. We reveal that the diazotrophs Crocosphaera watsonii and Trichodesmium contribute substantially to the bulk in situ Fe uptake (~33% on average over the studied area), despite being numerically less abundant compared to the rest of the planktonic community. Trichodesmium had the highest cell-specific Fe uptake rates, followed by C. watsonii, picoeukaryotes, Prochlorococcus, Synechococcus and finally heterotrophic bacteria. Calculated Fe:C quotas were higher (by 2 to 52-fold) for both studied diazotrophs compared to those of the non-diazotrophic plankton, reflecting their high intrinsic Fe demand. This translates into a diazotroph biogeographical distribution that appears to be influenced by ambient dissolved Fe concentrations in the WTSP. Despite having low cell-specific uptake rates, Prochlorococcus and heterotrophic bacteria were largely the main contributors to the bulk Fe uptake (~23% and ~12%, respectively). Overall, this group-specific approach increases our ability to examine the ecophysiological role of functional groups, including those of less abundant and/or less active microbes. 
PY 2022
PD APR
SO Isme Communications
SN 2730-6151
PU Springer Science and Business Media LLC
VL 2
IS 1
UT 001105650100001
DI 10.1038/s43705-022-00122-7
ID 87958
ER

EF