ORIGINAL ARTICLE Composition of supralittoral sediments bacterial communities in a Mediterranean island Giovanni Bacci & Ettore Pagoto & Maurizio Passaponti & Pietro Vannocci & Alberto Ugolini & Alessio Mengoni Received: 12 September 2013 /Accepted: 3 February 2014 /Published online: 27 February 2014 # Springer-Verlag Berlin Heidelberg and the University of Milan 2014 Abstract Marine coasts represent highly dynamic ecosys- tems, with sandy beaches being one of the most heteroge- neous. Despite the key importance of sandy beaches as tran- sition ecosystems between sea and land, very few studies on the microbiological composition of beach sediments have been performed. To provide a first description of microbial composition of supralittoral sediments, we investigated the composition of bacterial communities of three sandy beaches, at Favignana Island, Italy, using metagenetic approaches (Terminal-Restriction Fragment Length Polymorphism, se- quencing of 16S rRNA genes by Illumina-Solexa technology, functional genes detection, and quantitative Real-Time PCR). Results showed that the investigated beaches are harboring a rich bacterial diversity, mainly composed by members of classes Alphaproteobacteria , Gammaproteobacteria , Flavobacteria and Actinobacteria. The metagenetic analysis showed profiles of decreasing beta diversity and increasing richness, as well as a differentiation of communities, along the sea-to-land axis. In particular, members of Firmicutes and Proteobacteria displayed contrasting profiles of relative abun- dance (to decrease and to increase, respectively) along the sea- to-land axis of the beach. Finally, a search for the presence of genes related to the nitrogen and carbon biogeochemical cycle (nifH, nosZ, pmoA/amoA) detected the presence of ammonia monoxygenase sequences (amoA) only, suggesting the pres- ence of bacterial ammonia oxidation to some extent, probably due to members of Nitrospira, but with the lack of nitrogen fixation and denitrification. Keywords Supralittoral zone . Sandy beaches . Bacterial communities . T-RFLP . 16S rRNA gene . Metabarcoding Introduction Sandy beaches are world-wide distributed and are constantly subjected to biotic and abiotic disturbances, represented by natural and artificial bioturbation, seasonal and tidal tempera- ture fluctuation, erosion by currents, etc. (for a review see McLachlan and Brown 2006). In spite of their importance as an ecological transition zone between land and sea, and serious concerns for their ecolog- ical persistence (Brown and McLachlan 2002; Schlacher et al. 2007), only very recently the microbial ecology of sandy sediments, particularly concerning the submerged ones, has stirred attention (Gobet et al. 2012) and a census of web sites related to bacteria in sand has recently been published (Wackett 2013). Bacterial and fungal strains have been previ- ously isolated from beach sediments (Teplinskaia 1978; Figueira and Barata 2007; Jin et al. 2011), but very few investigations have been done aiming to describe the taxo- nomic composition of these sandy beaches (Rosano- Electronic supplementary material The online version of this article (doi:10.1007/s13213-014-0829-8) contains supplementary material, which is available to authorized users. G. Bacci : E. Pagoto : A. Ugolini : A. Mengoni (*) Department of Biology, University of Florence, Sesto Fiorentino Science Park, via Madonna del Piano 6, 50019 Sesto Fiorentino, Firenze, Italy e-mail: alessio.mengoni@unifi.it G. Bacci Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per lo Studio delle Relazioni tra Pianta e Suolo (CRA-RPS), Via della Navicella 2/4, 00184 Rome, Italy M. Passaponti Department of Chemistry, University of Florence, via della Lastruccia 13, 50019 Sesto Fiorentino, Italy P. Vannocci Department of Earth Science, University of Florence, via La Pira, 4, 50121 Florence, Italy Ann Microbiol (2015) 65:1–13 DOI 10.1007/s13213-014-0829-8