Global patterns of diversity and community structure in marine bacterioplankton

Abstract

Because of their small size, great abundance and easy dispersal, it is often assumed that marine planktonic microorganisms have a ubiquitous distribution that prevents any structured assembly into local communities. To challenge this view, marine bacterioplankton communities from coastal waters at nine locations distributed world-wide were examined through the use of comprehensive clone libraries of 16S ribosomal RNA genes, used as operational taxonomic units (OTU). Our survey and analyses show that there were marked differences in the composition and richness of OTUs between locations. Remarkably, the global marine bacterioplankton community showed a high degree of endemism, and conversely included few cosmopolitan OTUs. Our data were consistent with a latitudinal gradient of OTU richness. We observed a positive relationship between the relative OTU abundances and their range of occupation, i.e. cosmopolitans had the largest population sizes. Although OTU richness differed among locations, the distributions of the major taxonomic groups represented in the communities were analogous, and all local communities were similarly structured and dominated by a few OTUs showing variable taxonomic affiliations. The observed patterns of OTU richness indicate that similar evolutionary and ecological processes structured the communities. We conclude that marine bacterioplankton share many of the biogeographical and macroecological features of macroscopic organisms. The general processes behind those patterns are likely to be comparable across taxa and major global biomes.

Colorful microdiversity of Synechococcus strains (picocyanobacteria) isolated from the Baltic Sea

“…inhabit these environments (Ivanikova et al, 2007;Haverkamp et al, 2008). This is consistent with the conclusions of Pommier et al (2007), who found signals of endemism within the global bacterioplankton community. Therefore, we conclude that the high phylogenetic resolution provided by the cpcBA operon is useful to assess the microdiversity of Synechococcus strains in the Baltic Sea and other semienclosed ecosystems.…”

Methane production induced by dimethylsulfide in surface water of an upwelling ecosystem

“…Additionally, in a microcosm experiment where CH 4 is formed in DMSP spiked seawater, the CARD-FISH analysis shows that Archaea remained negligible in the DMSP supplemented approaches while Bacteria became nearly 100% of the community and alpha and gamma-proteobacteria together accounted for more than 75% of the DAPI-stained cells (Damm et al, 2010). Recent observations indicated that Alphaproteobacteria (including SAR11) and Rodobacteria are dominant in upwelling system off central Chile (Pommier et al, 2007;Aldunate, personal communication). The cosmopolitan distribution of Alphaproteobacteria supports the hypothesis that these bacteria are able to produce CH 4 in surface waters.…”

A biophysical perspective on dispersal and the geography of evolution in marine and terrestrial systems

“…Darling et al 2000;Esteban et al 2007; see also Brown & Hovmøller 2002). Most studies to date suggest that neither marine nor soil bacteria show the latitudinal diversity gradient (Baldwin et al 2005;Fierer & Jackson 2006), but there are recent exceptions (Pommier et al 2007) which may be common among larger microbes (e.g. tintinnids; Dolan et al 2006;see Finlay 2002); indeed, organisms with large, but subhemispheric, ranges are expected to show strong broad peaks in latitudinal diversity under the mid-domain model, with patterns of local species richness being modified by small-scale environmental heterogeneity (Colwell et al 2004(Colwell et al , 2005. )…”