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45° Congresso della Società Italiana di Biologia Marina
Venezia, 19-23 maggio 2014
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K.F.A. ABDELRHMAN, A. UGOLINI, M. SCHINTU*, A. MENGONI
Department of Biology, University of Florence,
Via Madonna del Piano, 6 - 50019 Sesto Fiorentino (FI), Italy.
alessio.mengoni@unifi.it
*Department of Health, Molecular and Clinical Medicine, University of Cagliari, Cagliari, Italy.

EXPLORING THE PATTERN OF SEASONAL DYNAMIC DIVERSITY
OF SARDINIAN SANDY SHORES MICROBIOMES

ESPLORAZIONE DELLE DINAMICHE DI DIVERSITÁ MICROBICA
STAGIONALE IN MICROBIOMI DI SPIAGGE SABBIOSE SARDE

Abstract - Sandy beaches have an important ecological role as transition zones between land and sea, but
to date have poorly been considered for their microbial communities. Here, we report results from an
analysis of bacterial communities (microbiomes) carried out with a cultivation-indepedent technique,
Terminal-Restriction Fragment Length Polymorphism (T-RFLP), in sandy beaches of Marine Protected
Areas of Sardinia. Data obtained showed that sandy beaches are hosting a considerable bacteria diversity,
which is influenced by seasonal changes. In particular, an increase of diversity in spring compared to
autumn was detected, as well as the presence of several taxa of marine origin. Further analyses will be
necessary to decipher the taxa most affected in relation to the seasonal change and define the functional
activities carried out by the sandy beach microbiome.

Key-words: microbiomes, sandy beaches, T-RFLP, Sardinia.

Introduction - Sandy beaches may be considered as filters that trap biocatalytic
substances of various nature coming from terrestrial and marine environment.
Microorganisms that inhabit marine sediments are possibly involved in the
mineralization of organic matter and degradation of pollutants, also regulate the
balance of various biogeochemical cycles. Despite of their ecological importance few
studies described microbial communities composition (microbiome) of supralittoral
sediments of sandy beaches. Very recently, we showed that supralittoral sediments in
Favignana Island, hold a large bacteria diversity (Bacci et al., in press), which could in
theory be influenced by geographical and seasonal variables. To address this last issue
we investigated the microbiome present in supralittoral sandy sediments of different
Marine Protected Areas of Sardinia (Italy) aiming to describe their taxonomic
composition and the temporal and spatial dynamics.
Materials and methods - 18 different sites in Sardinia were sampled in September
2012, May 2013 and October 2013. DNA was extracted from sand samples by using
Fast-DNA Kit for Soil (QBiogene), and 16S rRNA gene was amplified by using
799f/P6 universal bacterial primers. The taxonomic fingerprint of the microbiome was
defined by applying the Terminal-Restriction Fragment Length Polymorphism (T-
RFLP) technique on amplified DNA (Mengoni et al., 2007). Statistical and
bioinformatic analyses were performed as already described (Mengoni et al., 2013).
Results - Obtained results indicate that there are no geographically-related patterns of
microbiome diversity. On the contrary a strong effect of seasonal dynamics was
detected in biodiversity indices (Simpson, Shannon Wiever, Richness and Evenness
indices) with an increase of diversity in late spring compared to late summer-autumn
(up to 2.7 times). Finally, considering the taxonomic composition, members of phylum
Actinobacteria represented 46%. The phylum Protobacteria represented 37% of total

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