Contrasted geographical distribution of N$_2$ fixation rates and $nif$H phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions - Archive ouverte HAL Access content directly
Journal Articles Global Biogeochemical Cycles Year : 2015

Contrasted geographical distribution of N$_2$ fixation rates and $nif$H phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions

(1) , (2, 3) , (4) , (5, 3) , (6) , (7, 5) , (1) , (1) , (5) , (8) , (8) , (1) , (9, 10) , (5)
1
2
3
4
5
6
7
8
9
10
Sophie Bonnet
Sophie Cravatte

Abstract

Biological dinitrogen (N$_2$) fixation and the distribution of diazotrophic phylotypes were investigated during two cruises in the Coral Sea and the Solomon Sea (southwestern Pacific) during austral winter conditions. N$_2$ fixation rates were measurable at every station, but integrated (0-150 m) rates were an order of magnitude higher in the Solomon Sea (30 to 5449 $\mu$mol N m$^{-2}$ d$^{-1}$ compared to those measured in the Coral Sea (2 to 109 $\mu$ mol N m$^{-2}$ d$^{-1}$. Rates measured in the Solomon Sea were in the upper range (100-1000 mu mol N m$^{-2}$ d$^{-1}$ or higher than rates compiled in the global MARine Ecosystem biomass DATa database, indicating that this region has some of the highest N$_2$ fixation rates reported in the global ocean. While unicellular diazotrophic cyanobacteria from group A (UCYN-A1 and UCYN-A2) and the proteobacteria $\gamma$-24774A11 dominated in the Coral Sea and were correlated with N$_2$ fixation rates (p < 0.05), $Trichodesmium$ and UCYN-B dominated in the Solomon Sea and were correlated (p < 0.05) with N$_2$ fixation rates. UCYN-A were totally absent in the Solomon Sea. The biogeographical distribution of diazotrophs is discussed within the context of patterns in measured environmental parameters.
Fichier principal
Vignette du fichier
2015GB005117.pdf (3.87 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

hal-01496543 , version 1 (06-04-2021)

Identifiers

Cite

Sophie Bonnet, Martine Rodier, Kendra A. Turk-Kubo, Cyril Germineaud, Christophe E. Menkès, et al.. Contrasted geographical distribution of N$_2$ fixation rates and $nif$H phylotypes in the Coral and Solomon Seas (southwestern Pacific) during austral winter conditions. Global Biogeochemical Cycles, 2015, 29 (11), pp.1874 - 1892. ⟨10.1002/2015gb005117⟩. ⟨hal-01496543⟩
428 View
37 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More