Preprint volume - SIBM

Pre-print Volume – Posters
PLANKTON COMMITEE
G. RUGGERI, M. BORGHINI 1 , A. RIBOTTI 2 , M. MILICI, M. PAPALE,
R. SORGENTE 2 , M. DE DOMENICO, E. DE DOMENICO
Dip. Biologia Animale ed Ecologia Marina, Università di Messina, Salita Sperone, 31 – Messina, Italia.
edd@unime.it
1 Istituto di Scienze Marine (ISMAR - CNR), Pozzuolo di Lerici (SP), Italia.
2 Istituto per l’Ambiente Marino Costiero (IAMC-CNR), Loc. Sa Mardini, Torregrande (OR), Italia.
LUMINOUS MARINE BACTERIA AND WATER MASSES
DISTRIBUTION IN THE CENTRAL MEDITERRANEAN SEA
(CRUISE SICILY09)
DISTRIBUZIONE DI BATTERI LUMINOSI E MASSE D’ACQUA
NEL MAR MEDITERRANEO CENTRALE (CROCIERA SICILY09)
Abstract – To evaluate quantitative and qualitative luminescent bacteria (LB) distribution, 421 seawater
samples from 38 stations of the Central Mediterranean Sea were analysed during November 2009. LB plate
counts showed a patchiness bacterial distribution with increase near the bottom. An ARDRA analysis on
isolated strains was carried out to evaluate the microbial diversity of the luminous communities.
Key-words: bacteria, distribution, luminous organisms, water masses.
Introduction - To date, a wide literature on the systematic, metabolic features,
biochemical pathways and ecology of luminous bacteria (LB) is available. Conversely,
their distribution and role in marine environment show a lack of knowledge. During
last years, we have deeply studied marine LB in different basins of the Mediterranean
Sea by using various approaches, as viable counts, phenotypic assays and genotypic
techniques (De Luca et al., 2009; Gentile et al., 2009). Marked differences in viable
counts and bacterial genera distribution, in the surveyed areas of the Mediterranean
Sea, were observed. De Luca et al. (2009) found higher values on surface waters (0-
200 m) in the western Mediterranean Sea and at 800-1200 m depth in all
Mediterranean surveyed areas. Genera distribution also varied with depth. The Central
Mediterranean Sea hydrology is characterised by a really complex bottom topography
directly influencing water exchanges between E and W Mediterranean basins. The
Sicily Strait is characterised by two narrow passages giving strong limits to the
exchanges with the E Mediterranean Sea. The Tyrrhenian Sea is linked with E
Mediterranean Sea through a shallow channel permitting the inflow of Levantine
Intermediate Water (LIW) and transitional Eastern Mediterranean Deep Water
(tEMDW) that, sinking at the entrance of this sub-basin, origins the Tyrrhenian Deep
Water (TDW), then moving over the Western Mediterranean Deep Water (WMDW),
as referred by Astraldi et al. (2002).
Materials and methods – From 30/10 to 23/11/2009 a multidisciplinary cruise
(SICILY09) was carried out on board the R/V Urania of the CNR in the central and
western Mediterranean basins. Water samples were collected, from surface to 10m
above the bottom, by a Rosette sampler equipped with 12L Niskin bottles. A CTD
probe 911plus SeaBird was employed for conductivity, temperature, pressure,
dissolved oxygen and fluorescence measurements. LB were counted on Millipore
filters (0.45 μm) placed on Sea Water Complete (SWC) agar plates. Counts from
various filtered volumes and duplicate plates, were normalized to 100 ml. ARDRA
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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