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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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