@article{fdi:010082655,
  title = {{D}iazotroph-derived nitrogen assimilation strategies differ by scleractinian coral species},
  author = {{M}eunier, {V}. and {B}onnet, {S}ophie and {B}enavides, {M}ar and {R}avache, {A}. and {G}rosso, {O}. and {L}ambert, {C}. and {H}oulbr{\`e}que, {F}anny},
  editor = {},
  language = {{ENG}},
  abstract = {{R}eef-building corals generally thrive in nutrient-poor tropical waters, where among other elements, nitrogen ({N}) availability often limits primary productivity. {I}n addition to their close association with endosymbiotic dinoflagellates of the family {S}ymbiodiniaceae, enabling an effective use and retention of dissolved inorganic nitrogen ({DIN}), scleractinian corals have developed strategies to acquire new {N}: (1) {T}hey can ingest {N}-rich sediment particles and preys (from picoplankton to macro-zooplankton) via heterotrophy, including diazotrophs [plankton fixing dinitrogen ({N}2) and releasing part of this nitrogen-{D}iazotroph-{D}erived {N} ({DDN})-in seawater], a pathway called "heterotrophic nutrition on diazotrophs"; (2) {S}ymbiotic diazotrophs located in the coral holobiont have the molecular machinery to fix {N}2, a pathway called "symbiotic {N}2 fixation". {H}ere we used the 15{N}2 isotopic labeling in a series of incubations to investigate the relative contribution of each of these {DDN} transfer pathways in three worldwide distributed coral species: {A}cropora muricata, {G}alaxea fascicularis, and {P}ocillopora damicornis. {W}e show that {N} provision via "symbiotic {N}2 fixation" is negligible compared to that obtained via "heterotrophic nutrition on diazotrophs," with {DDN} assimilation rates about a thousand times lower for {P}. damicornis and {G}. fascicularis, or assimilation rates via "symbiotic {N}2 fixation" almost nil for {A}. muricata. {T}hrough heterotrophic feeding on planktonic diazotrophs, only {G}. fascicularis and {P}. damicornis can successfully obtain {N} and fulfill a large part of their {N} requirements ({DDN} asimilation rates: 0.111 +/- 0.056 and 0.517 +/- 0.070 mu g {N} cm-2 h-1 in their {S}ymbiodiniaceae, respectively). {W}hereas this contribution is again negligible for {A}. muricata. {T}hey also largely consume the picoplankton that likely benefit from this {DDN} ({P}rochlorococcus and {S}ynechococcus cells; respectively, 2.56 +/- 1.57 104 and 2.70 +/- 1.66 104 cell h-1 cm-2 for {G}. fascicularis; 3.02 +/- 0.19 105 and 1.14 +/- 0.79 104 cell h-1 cm-2 for {P}. damicornis). {T}he present study confirms the different dependencies of the three tested species regarding heterotrophy, with {P}. damicornis and {G}. fascicularis appearing highly efficient at capturing plankton, while {A}. muricata, considered as mainly autotroph, does not rely on these food resources to meet its {N} and energy needs.},
  keywords = {dinitrogen fixation ; {DDN} assimilation ; scleractinian corals ; heterotrophy ; diazotrophs ; picoplankton ; {N}ew {C}aledonia ; {NOUVELLE} {CALEDONIE} ; {PACIFIQUE}},
  booktitle = {},
  journal = {{F}rontiers in {M}arine {S}cience},
  volume = {8},
  numero = {},
  pages = {692248 [11 ]},
  year = {2021},
  DOI = {10.3389/fmars.2021.692248},
  URL = {https://www.documentation.ird.fr/hor/fdi:010082655},
}