%0 Journal Article
%T Planktonic dinitrogen fixation along a longitudinal gradient across the Mediterranean Sea during the stratified period (BOUM cruise)
%+ Institut méditerranéen d'océanologie (MIO)
%+ Laboratoire d'océanographie et de biogéochimie (LOB)
%A Bonnet, Sophie
%A Grosso, Olivier
%A Moutin, Thierry
%Z The publication of this article is financed by CNRS-INSU
%< avec comité de lecture
%Z MIO:11-104
%@ 1726-4170
%J Biogeosciences
%I European Geosciences Union
%V 8
%N 8
%P 2257-2267
%8 2011
%D 2011
%R 10.5194/bg-8-2257-2011
%K TROPICAL ATLANTIC
%K TRICHODESMIUM SPP.
%K PHOSPHORUS LIMITATION
%K PRIMARY PRODUCTIVITY
%K NORTH PACIFIC-OCEAN
%K NITROGEN-FIXATION
%K N-2 FIXATION
%K ATMOSPHERIC DEPOSITION
%K PHOSPHATE AVAILABILITY
%K HIGH-RATES
%Z Sciences of the Universe [physics]/Earth Sciences/OceanographyJournal articles
%X This study provides extensive data on planktonic N-2 fixation rates across the whole Mediterranean Sea. They show that N-2 fixation occurs in Mediterranean waters during the stratification period, with a clear decreasing trend from the oligotrophic western basin (10-76 mu mol m(-2) d(-1)) to the ultra oligotrophic eastern basin (0-0.4 mu mol m(-2) d(-1)). Highest rates are measured in the less oligotrophic western basin, between the surface and 75 m-depth, where 45 to 75% of N-2 fixation are found within the picoplanktonic fraction (<3 mu m). While the biogeochemical impact of N-2 fixation in the eastern basin seems negligible, N-2 fixation is able to sustain up to 35% of new primary production during the stratified period in the western basin. These data disagree with indirect estimates of N-2 fixation based on geochemical tracers and nutrient budgets, which indicates that N-2 fixation increases with increasing N:P ratios and decreasing stable N isotopic signature of particulate organic nitrogen and NO3- from west to east. These results finally point out the need to assess N-2 fixation at a higher temporal resolution in order to better understand the diazotrophs' dynamic under contrasted biogeochemical conditions.
%G English
%2 https://hal.science/hal-00724468/document
%2 https://hal.science/hal-00724468/file/bg-8-2257-2011.pdf
%L hal-00724468
%U https://hal.science/hal-00724468
%~ IRD
%~ INSU
%~ UNIV-TLN
%~ CNRS
%~ UNIV-AMU
%~ MIO
%~ OSU-INSTITUT-PYTHEAS
%~ GIP-BE
%~ LOPB
%~ MIO-CYBELE
%~ TEST3-HALCNRS