Distinct bacterial groups contribute to carbon cycling during a naturally iron fertilized phytoplankton bloom in the Southern Ocean

Type Article
Date 2011-11
Language English
Author(s) Obernosterer Ingrid1, 2, Catala Philippe1, 2, Lebaron Philippe1, 2, 3, West Nyree J.1, 3
Affiliation(s) 1 : Univ Paris 06, Observ Oceanol, Lab Oceanog Microbienne, UMR 7621,UMS 2348, Banyuls Sur Mer, France.
2 : CNRS, Observ Oceanol, Lab Oceanog Microbienne, UMR 7621, Banyuls Sur Mer, France.
3 : CNRS, Observ Oceanol, UMS 2348, Banyuls Sur Mer, France.
Source Limnology And Oceanography (0024-3590) (Amer Soc Limnology Oceanography), 2011-11 , Vol. 56 , N. 6 , P. 2391-2401
DOI 10.4319/lo.2011.56.6.2391
WOS© Times Cited 26
Abstract We investigated the contribution of distinct bacterial groups to bulk abundance and leucine incorporation during a spring phytoplankton bloom induced by natural iron fertilization in the Southern Ocean (Kerguelen Ocean and Plateau Compared Study, January-February 2005). Oligonucleotide probes were designed to target five operational taxonomic units (OTUs) at a narrow phylogenetic level (>= 99% identity of the 16S ribosomal ribonucleic acid [rRNA] gene). During the peak of the phytoplankton bloom, the Roseobacter groups NAC11-7 and RCA, the OTUs SAR92 belonging to Gammaproteobacteria, and the Bacteroidetes OTU Agg58 dominated bulk abundance and leucine incorporation. These four OTUs disappeared with the decline of the bloom, when the cosmopolitan groups SAR11 and SAR86 became dominant. In high-nutrient, low-chlorophyll waters and at a site characterized by transient high phytoplankton biomass, the SAR11 and SAR86 clusters and a Polaribacter OTU dominated abundance and leucine incorporation in the upper 100 m. Our results demonstrate that a few distinct bacterial groups identified on a relatively narrow phylogenetic level account for 47% to 82% of bulk abundance and leucine incorporation during the spring phytoplankton bloom in the naturally fertilized region off Kerguelen. The major role of these bacterial groups in carbon cycling in response to natural iron fertilization in the Southern Ocean suggests they could play an important role in the coupling of the biogeochemical cycles of carbon and iron.
Full Text
File Pages Size Access
Publisher's official version 11 554 KB Open access
Top of the page