Heterogeneity in the nutrient limitation of different bacterioplankton groups in the Eastern Mediterranean Sea

4 pages, 2 figuresThe heterotrophic bacterial community of the Eastern Mediterranean Sea is believed to be limited by phosphorus (P) availability. This observation assumes that all bacterial groups are equally limited, something that has not been hitherto examined. To test this hypothesis, we performed nutrient addition experiments and investigated the response of probe-identified groups using microautoradiography combined with catalyzed reporter deposition fluorescence in situ hybridization. Our results show contrasting responses between the bacterial groups, with Gammaproteobacteria being the group more affected by P availability. The Roseobacter clade was likely colimited by P and nitrogen (N), whereas Bacteroidetes by P, N and organic carbon (C). In contrast, SAR11 cells were active regardless of the nutrient concentration. These results indicate that there is high heterogeneity in the nutrient limitation of the different components of the bacterioplankton community. © 2013 International Society for Microbial Ecology. All rights reservedThis experiment in the Cretacosmos facility was arranged in co-operation by project Nutritunnel financed by the Research Council of Norway and the MESOAQUA network (FP7/2007-2013, grant agreement no. 228224). [...] Processing of the samples was supported by the grants FOSMICRO (CTM2009-07679-E) and STORM (CTM2009-09352/MAR), funded by the former Spanish Ministry of Science and Innovation. MS was supported by a ‘Juan de la Cierva’ awardPeer Reviewe