Page 11 - Bacc_Pagoto_&C_2015

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10 Ann Microbiol (2015) 65:1–13

Bacillaceae genus distribution Alteromonadaceae genus distribution
1.00 1.00

0.75 0.75
Genus
Bacillus Genus
Percentage 0.50 Pontibacillus Percentage 0.50 Marinobacter
Virgibacillus
Other
Halobacillus
Halothiobacillus
Other
0.25 0.25
0.00 0.00
shore−line mid−line upper−line shore−line mid−line upper−line

Rhodobacteraceae genus distribution Erythrobacteraceae genus distribution
1.00 1.00
Genus
Rhodovulum
0.75 Ahrensia 0.75
Ruegeria Genus
Percentage 0.50 Salipiger Percentage 0.50 Erythrobacter
Oceanicola
Roseovarius
Altererythrobacter
Maribius
Loktanella Other
0.25 Shimia 0.25
Sulfitobacter
Other
0.00 0.00
shore−line mid−line upper−line shore−line mid−line upper−line
Ectothiorhodospiraceae genus distribution
1.00

0.75
Genus
Percentage 0.50 Thioalkalivibrio
Alkalispirillum
Alkalilimnicola
Thiohalospira
Other
0.25
0.00
shore−line mid−line upper−line
Fig. 5 Composition of genera of the main families of Alphaproteobacteria and Bacillales. The relative proportion of genera for Bacillaceae,
Alteromonadaceae, Rhodobacteraceae, Erythrobacteraceae,and Ectothiorhodospiraceae is reported

water (Zweifel and Hagstrom 1995). Moreover, a high bacterial Y-axis. In particular, locations showed different organic car-
diversity was also found, suggesting that bacterial communities bon content (see Table 1), which could be related to the
could have active roles in biogeochemical cycling on a sandy differences observed between communities. However, no re-
beach ecosystem. The detected biodiversity is mainly ascribed to lationships between organic carbon percentage and ribotype
Proteobacteria, Actinobacteria and Bacteroidetes phyla and to richness was observed.
the orders of Flavobacteriales, Actynomicetales, Rhizobiales, For what is of concern for the differentiation of communi-
Rhodobacterales, Bacillales, Alteromonadales, Chromatiales, ties along the Y-axis, the metagenetic analysis of Faraglioni
and Oceanospirillales. Within these groups, several well known beach showed a decreasing beta diversity and an increasing
marine taxa (Rusch et al. 2007) can be found (e.g., in richness (alpha diversity) along the sea-to-land axis, suggest-
Oceanospirillales, Chromatiales and Rhodobacterales), suggest- ing a tendency i) for a lower differentiation when proceeding
ing that a consistent part of sandy beaches microbiota is of along the axis (may be due to more homogeneous environ-
marine origin. mental parameters), and ii) for an increasing number of taxa
Moreover, by comparing bacterial community fingerprint- (may be linked to proximity with soil). Among the identified
ing (T-RFLP profiles) of sandy beaches of three different bacterial groups with differences of abundance along the axis,
localities we have shown a considerable heterogeneity of two main bacterial phyla have opposite trends of abundance
samples, either due to location and to the position along the along the Y-axis: Firmicutes and Proteobacteria. Within