%0 Journal Article
%T High abundance of diazotrophic picocyanobacteria (< 3 mu m) in a Southwest Pacific coral lagoon
%+ Caractérisation et modélisation des échanges dans des lagons soumis aux influences terrigènes et anthropiques (CAMELIA)
%A Biegala, Isabelle C.
%A Raimbault, Patrick
%< avec comité de lecture
%Z MIO:08-103
%@ 0948-3055
%J Aquatic Microbial Ecology
%I Inter Research
%V 51
%P 45-53
%8 2008
%D 2008
%R 10.3354/ame01185
%K diazotrophs
%K picoplankton
%K FISH
%K Pacific
%K coral lagoon
%K symbiosis
%K 16S RIBOSOMAL-RNA
%K TARGETED OLIGONUCLEOTIDE PROBES
%K TROPICAL NORTH-ATLANTIC
%K IN-SITU IDENTIFICATION
%K NITROGEN-FIXATION
%K CONFOCAL MICROSCOPY
%K COMMUNITY STRUCTURE
%K N-2 FIXATION
%K OCEAN
%K CYANOBACTERIA
%Z Life Sciences [q-bio]/Ecology, environment/Symbiosis
%Z Environmental Sciences/Biodiversity and Ecology
%Z Environmental Sciences/Global Changes
%Z Environmental Sciences/Environmental Engineering
%Z Life Sciences [q-bio]/Ecology, environment/Ecosystems
%Z Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology
%Z Life Sciences [q-bio]/Biotechnology
%Z Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy
%Z Computer Science [cs]/BiotechnologyJournal articles
%X In the present study we detected unicellular diazotrophic cyanobacteria along a nutrient gradient in New Caledonia's coral lagoon (24 000 km(2)) using whole-cell hybridization of specific Nitro821 probes (TSA-FISH, Tyramide Signal Amplification of Fluorescent In Situ Hybridization). The specificity of this probe was confirmed on cultures and in the natural environment, Surprisingly, the community of Nitro821-targeted cells was numerically dominated by picocyanobacteria (97%, 1 to 1.5 mu m). These organisms were either free living (63%), recovered with the 0.2 to 3 mu m size fraction or associated (37%) to particles or planktonic dinoflagellates from larger size fractions (3 to 10 mu m and >10 mu m). Diazotrophic picocyanobacterial abundance ranged from 3 to 140 cells ml(-1) along the nutrient gradient and was highest at the oligotrophic lagoonal station. These cells may contribute to N-2 fixation from the < 10 mu m size fraction (4.4 to 8 nmol N-1 24 h(-1)), which was 4 times higher than the >10 mu m size fraction (0 to 1.9 nmol N-1 24 h(-1)). In addition, in the middle of the lagoon daylight N-15(2) fixation could explain 78% of N-15(2) fixation over 24 h. The results presented in the present study reveal for the first time a significant concentration of photosynthetic diazotrophs within the marine picoplankton community.
%G English
%L hal-00727031
%U https://hal.science/hal-00727031
%~ SDE
%~ GIP-BE