@article{fdi:010085391,
  title = {{S}inking {T}richodesmium fixes nitrogen in the dark ocean},
  author = {{B}enavides, {M}ar and {B}onnet, {S}ophie and {L}e {M}oigne, {F}. {A}. {C}. and {A}rmin, {G}. and {I}nomura, {K}. and {H}allstrom, {S}. and {R}iemann, {L}. and {B}erman-{F}rank, {I}. and {P}oletti, {E}. and {G}arel, {M}. and {G}rosso, {O}. and {L}eblanc, {K}. and {G}uigue, {C}. and {T}edetti, {M}arc and {D}upouy, {C}{\'e}cile},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he photosynthetic cyanobacterium {T}richodesmium is widely distributed in the surface low latitude ocean where it contributes significantly to {N}-2 fixation and primary productivity. {P}revious studies found nif{H} genes and intact {T}richodesmium colonies in the sunlight-deprived meso- and bathypelagic layers of the ocean (200-4000 m depth). {Y}et, the ability of {T}richodesmium to fix {N}-2 in the dark ocean has not been explored. {W}e performed {N}-15(2) incubations in sediment traps at 170, 270 and 1000 m at two locations in the {S}outh {P}acific. {S}inking {T}richodesmium colonies fixed {N}-2 at similar rates than previously observed in the surface ocean (36-214 fmol {N} cell(-1) d(-1)). {T}his activity accounted for 40 +/- 28% of the bulk {N}-2 fixation rates measured in the traps, indicating that other diazotrophs were also active in the mesopelagic zone. {A}ccordingly, c{DNA} nif{H} amplicon sequencing revealed that while {T}richodesmium accounted for most of the expressed nif{H} genes in the traps, other diazotrophs such as {C}hlorobium and {D}eltaproteobacteria were also active. {L}aboratory experiments simulating mesopelagic conditions confirmed that increasing hydrostatic pressure and decreasing temperature reduced but did not completely inhibit {N}-2 fixation in {T}richodesmium. {F}inally, using a cell metabolism model we predict that {T}richodesmium uses photosynthesis-derived stored carbon to sustain {N}-2 fixation while sinking into the mesopelagic. {W}e conclude that sinking {T}richodesmium provides ammonium, dissolved organic matter and biomass to mesopelagic prokaryotes.},
  keywords = {{PACIFIQUE} {SUD} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{ISME} {J}ournal},
  volume = {[{E}arly access]},
  numero = {},
  pages = {[8 p.]},
  ISSN = {1751-7362},
  year = {2022},
  DOI = {10.1038/s41396-022-01289-6},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085391},
}