@article{fdi:010067775,
  title = {{G}lobal analysis of gene expression dynamics within the marine microbial community during the {VAHINE} mesocosm experiment in the southwest {P}acific},
  author = {{P}freundt, {U}. and {S}pungin, {D}. and {B}onnet, {S}ophie and {B}erman-{F}rank, {I}. and {H}ess, {W}. {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{M}icrobial gene expression was followed for 23 days within a mesocosm ({M}1) isolating 50m(3) of seawater and in the surrounding waters in the {N}oumea lagoon, {N}ew {C}aledonia, in the southwest {P}acific as part of the {VA}riability of vertical and trop{HI}c transfer of diazotroph derived {N} in the south w{E}st {P}acific ({VAHINE}) experiment. {T}he aim of {VAHINE} was to examine the fate of diazotroph-derived nitrogen ({DDN}) in a low-nutrient, low-chlorophyll ecosystem. {O}n day 4 of the experiment, the mesocosm was fertilized with phosphate. {I}n the lagoon, gene expression was dominated by the cyanobacterium {S}ynechococcus, closely followed by {A}lphaproteobacteria. {I}n contrast, drastic changes in the microbial community composition and transcriptional activity were triggered within the mesocosm within the first 4 days, with transcription bursts from different heterotrophic bacteria in rapid succession. {T}he microbial composition and activity of the surrounding lagoon ecosystem appeared more stable, although following similar temporal trends as in {M}1. {W}e detected significant gene expression from {C}hromerida in {M}1, as well as the {N}oumea lagoon, suggesting these photoautotrophic alveolates were present in substantial numbers in the open water. {O}ther groups contributing substantially to the metatranscriptome were affiliated with marine {E}uryarchaeota {C}andidatus {T}halassoarchaea (inside and outside) and {M}yoviridae bacteriophages likely infecting {S}ynechococcus, specifically inside {M}1. {H}igh transcript abundances for ammonium transporters and glutamine synthetase in many different taxa (e.g., {P}elagibacteraceae, {S}ynechococcus, {P}rochlorococcus, and {R}hodobacteraceae) was consistent with the known preference of most bacteria for this nitrogen source. {I}n contrast, {A}lteromonadaceae highly expressed urease genes; {R}hodobacteraceae and {P}rochlorococcus showed some urease expression, too. {N}itrate reductase transcripts were detected on day 10 very prominently in {S}ynechococcus and in {H}alomonadaceae. {A}lkaline phosphatase was expressed prominently only between days 12 and 23 in different organisms, suggesting that the microbial community was not limited by phosphate, even before the fertilization on day 4, whereas the post-fertilization community was. {W}e observed high expression of the {S}ynechococcus sqd{B} gene, only transiently lowered following phosphate fertilization. {S}qd{B} encodes {UDP}-sulfoquinovose synthase, possibly enabling marine picocyanobacteria to minimize their phosphorus requirements by substitution of phospholipids with sulphur-containing glycerolipids. {T}his result suggests a link between sqd{B} expression and phosphate availability in situ. {G}ene expression of diazotrophic cyanobacteria was mainly attributed to {T}richodesmium and {R}ichelia intracellularis (diatom-diazotroph association) in the {N}oumea lagoon and initially in {M}1. {UCYN}-{A} ({C}andidatus {A}telocyanobacterium) transcripts were the third most abundant and declined both inside and outside after day 4, consistent with 16{S}- and nif{H}-based analyses. {T}ranscripts related to the {E}pithemia turgida endosymbiont and {C}yanothece {ATCC} 51142 increased during the second half of the experiment.},
  keywords = {{NOUVELLE} {CALEDONIE} ; {PACIFIQUE} {SUD} {OUEST}},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {13},
  numero = {14},
  pages = {4135--4149},
  ISSN = {1726-4170},
  year = {2016},
  DOI = {10.5194/bg-13-4135-2016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010067775},
}