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           Ann Microbiol (2015) 65:1–13                                                                     11

           Firmicutes, the main portion was constituted by sequences  and in a pelagic form, may help colonization (Fuerst, and
           attributed to the spore-forming aerobic taxon of Bacillaceae,  Sagulenko 2011). Actually, Planctomycetes have been found
           more abundant in the damp band, with genera Bacillus and  as dominant in some intertidal sediment communities (Musat
           Halobacillus being the most represented. Concerning  et al. 2006). Other phyla, as Chloroflexi, Deinococcus−
           Proteobacteria, the alphaproteobacterial family    Thermus, Spirochaetes, Verrucomicrobia and Clamydiae also
           Rhodobacteraceae was the most abundant along all the tran-  show differential presence along the beach Y-axis, and may
           sect. For this family a large number of sequences from the  represent peculiar adaptation or marker taxa for the upper-line
           marine sulfur-oxidizing genus Sulfitobacter (Pukall et al.  (e.g., Clamydiae and Verrucomicrobia). These phyla are rela-
           1999) was detected, allowing one to hypothesize that some  tively rare in our metagenetic dataset but, as recently shown for
           sulfur cycle may also occur on supralittoral sediments.  the rhizosphere (Dohrmann et al. 2013)aswellasfor marine
           Actually, most of bacterial taxa known to be abundant in sea  sediments (Gobet et al. 2012), rare taxa may better explain
           water were also well present in the supralittoral sediments, as  ecological adaptation of communities than abundant taxa and
           Erythrobacteraceae, Ectothiorhodospiraceae and     may provide a “seed bank” for bacterial colonization.
           Alteromonadaceae. Erythrobacteraceae (as also        Finally, concerning the possible functions promoted by
           Rhodobacteraceae) is a family of Alphaproteobacteria com-  bacterial communities here investigated, we did not detect
           posed by strains mainly isolated from aquatic environments,  the presence of genes related to nitrogen fixation (nifH),
           and the genus most represented in our dataset was  denitrification (nosZ) and methane oxidation (pmoA).
           Erythrobacter (see for instances (Lee et al. 2005 and  However, some samples showed the presence of ammonia
           references therein). Ectothiorhodospiraceae is a group of  monoxygenase (amoA) genes. By comparison with the meta-
           halophilic and haloalkaliphilic Gammaproteobacteria  genetic sequencing of Faraglioni beach, we cannot a priori
           (Tourova et al. 2007), which includes strains with known  exclude that the (very few) detected Nitrospira may be mainly
           “extremophyilic” phenotypes but also able to fix nitrogen  responsible for amoA genes. Nitrospira is a well known taxon
           and participate in sulfur and iron biogeochemical cycles  of marine ammonia-oxidizing bacteria (see for instance
           (see for instance Hallberg et al. 2011). Indeed, the most  Haaijer et al. 2013 and references therein). We can then
           abundant genus belonging to Ectothiorhodospiraceae  speculate that bacterial ammonia oxidation could be occasion-
           foundinour datasetwas Thiohalospira, a genus of    ally present in sandy beaches and may contribute to the input
           recently discovered chemolithoautotrophic, halophilic,  of nitrite in the sandy beach ecosystem. However, more sam-
           sulfur-oxidizing gammaproteobacteria (Sorokin et al.  pling along the seasons, as well as dedicated molecular studies
           2008). Alteromonadaceae is another well known      with metagenetic sequencing of amoA genes, will be needed
           gammaproteobacterial family of marine strains (Ivanova  to infer possible functionality in the nitrogen biogeochemical
           and Mikhailov 2001). Here the genus Marinobacter,  cycle of sandy beach bacterial communities.
           which include strains able to degrade hydrocarbons
           (Cui et al. 2008), was indeed dominant. Interestingly,
                                                              Acknowledgments We are grateful to the Marine Protected Area “Isole
           within the most abundant phyla, also Acidobacteria and
                                                              Egadi” for authorization to obtain samplings. This work was supported by
           Actinobacteria were represented, with a discontinuous pattern  intramural funding (Fondo di Ateneo, ex 60%) of the University of
           along the Y-axis. In particular, Actinobacteria were less abun-  Florence to AU and AM.
           dant in the mid-line sample, possibly implying the presence of
           both marine taxa for this phylum (Bull et al. 2005) (mainly
           colonizing the shore-line sample) and soil taxa (mainly colo-
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