@article{fdi:010066683,
  title = {{I}mportance of {N}-2-fixation on the productivity at the {N}orth-{W}estern {A}zores current/front system, and the abundance of diazotrophic unicellular cyanobacteria},
  author = {{R}iou, {V}. and {F}onseca-{B}atista, {D}. and {R}oukaerts, {A}. and {B}iegala, {I}sabelle and {P}rakya, {S}. {R}. and {L}oureiro, {C}. {M}. and {S}antos, {M}. and {M}uniz-{P}iniella, {A}. {E}. and {S}chmiing, {M}. and {E}lskens, {M}. and {B}rion, {N}. and {M}artins, {M}. {A}. and {D}ehairs, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}o understand the impact of the northwestern {A}zores {C}urrent {F}ront ({NW}-{A}z{C}/{A}z{F}) system on {HCO}3-- and {N}-2-fixation activities and unicellular diazotrophic cyanobacteria ({UCYN}) distribution, we combined geochemical and biological approaches from the oligotrophic surface to upper mesopelagic waters. {N}-2-fixation was observed to sustain 45-85% of the {HCO}3--fixation in the picoplanktonic fraction performing 47% of the total {C}-fixation at the deep chlorophyll maximum north and south of the {A}z{F}. {N}2-fixation rates as high as 10.9 mu mol {N} m(-3) d(-1) and surface nitrate delta {N}-15 as low as 2.7 parts per thousand were found in the warm (18-24 degrees {C}), most saline (36.5-37.0) and least productive waters south of the {A}z{F}, where {UCYN} were the least abundant. {H}owever, picoplanktonic {UCYN} abundances up to 55 cells m{L}(-1) were found at 45-200m depths in the coolest nutrient-rich waters north of the {A}z{F}. {I}n this area, {N}-2-fixation rates up to 4.5 mu mol {N} m(-3) d(-1) were detected, associated with depth-integrated ({HCO}3-)-{C}-13-fixation rates at least 50% higher than observed south of the {A}z{F}. {T}he numerous eddies generated at the {NW}-{A}z{C}/{A}z{F} seem to enhance exchanges of plankton between water masses, as well as vertical and horizontal diapycnal diffusion of nutrients, whose increase probably enhances the growth of diazotrophs and the productivity of {C}-fixers.},
  keywords = {{ATLANTIQUE} ; {PORTUGAL} ; {ACORES}},
  booktitle = {},
  journal = {{P}los {O}ne},
  volume = {11},
  numero = {3},
  pages = {e0150827 [22 p.]},
  ISSN = {1932-6203},
  year = {2016},
  DOI = {10.1371/journal.pone.0150827},
  URL = {https://www.documentation.ird.fr/hor/fdi:010066683},
}