@article{fdi:010080067,
  title = {{S}easonal shifts in {D}iazotrophs players: patterns observed over a two-year time series in the {N}ew {C}aledonian lagoon ({W}estern tropical {S}outh {P}acific ocean)},
  author = {{S}aulia, {E}mmrick and {B}enavides, {M}ar and {H}enke, {B}. and {T}urk-{K}ubo, {K}. and {C}ooperguard, {H}. and {G}rosso, {O}. and {D}esnues, {A}nne and {R}odier, {M}artine and {D}upouy, {C}{\'e}cile and {R}iemann, {L}. and {B}onnet, {S}ophie},
  editor = {},
  language = {{ENG}},
  abstract = {{C}oastal and open ocean regions of the {W}estern {T}ropical {S}outh {P}acific ocean have been identified as a hotspot of {N}2 fixation. {H}owever, the environmental factors driving the temporal variability of abundance, composition, and activity of diazotrophs are still poorly understood, especially during the winter season. {T}o address this, we quantified {N}2 fixation rates and the abundance of seven diazotroph phylotypes ({UCYN}-{A}1 symbiosis, {UCYN}-{B}, {UCYN}-{C}, {T}richodesmium, {H}et-1, {H}et-2, and {H}et-3) on a monthly basis during two full years (2012 to 2014) at four stations along a coast to open ocean transect in the {N}ew {C}aledonian lagoon. {T}he total nif{H} gene concentration (sum of all nif{H} gene copies) clearly decreased from the barrier reef to the shore. {A}part from {UCYN}-{B}, which peaked at very high abundances (10 6-10 8 nif{H} gene copies {L} -1) at two occasions at the coastal station, the {UCYN}-{A}1 symbiosis was the most abundant group at all stations, accounting for 79% of the total nif{H} gene copy counts along the transect (average abundance 4.2 +/- 10.3 x 10 4 nif{H} gene copies {L}-1). {T}he next most abundant groups were in order {T}richodesmium (accounting for 14% of the total nif{H} gene copies), {H}et-groups (6% of the total) and {UCYN}-{C} (1% of the total). {S}tatistical analyses reveal that the {UCYN}-{A}1 symbiosis and {H}et groups were associated with cold (<25°{C}) waters, high {NO}x and {PO}4 3-, weak winds from the south (occasionally southwest), while {T}richodesmium and {UCYN}-{C} were associated with warmer (>25°{C}) waters, low {NO}x and {PO}4 3- concentrations, strong and (mostly) easterly winds. {A}verage {N}2 fixation rates over the survey were 6.5 +/- 6.7 nmol {N} {L}-1 d-1 and did not differ significantly among seasons. {T}he year to year variability was more pronounced with average integrated rates significantly higher in the second year of the survey (162 +/- 122 mmol {N} m-2 d-1) than the first year (66 +/-91 mmol {N} m-2 d-1). {T}his dataset suggests that seasonality is less pronounced than previously thought, and that relatively high {N}2 fixation rates are maintained in the {N}ew {C}aledonian lagoon all year long, despite seasonal changes in the diazotroph community composition.},
  keywords = {{BACTERIE} ; {ABONDANCE} ; {FIXATION} {BIOLOGIQUE} {DE} {L}'{AZOTE} ; {CYCLE} {BIOGEOCHIMIQUE} ; {PRODUCTION} {BIOLOGIQUE} ; {BENTHOS} ; {LAGON} ; {MILIEU} {MARIN} ; {NOUVELLE} {CALEDONIE} ; {PACIFIQUE}},
  booktitle = {},
  journal = {{F}rontiers in {M}arine {S}cience},
  volume = {7},
  numero = {},
  pages = {581755 [11 ]},
  ISSN = {2296-7745},
  year = {2020},
  DOI = {10.3389/fmars.2020.581755},
  URL = {https://www.documentation.ird.fr/hor/fdi:010080067},
}