Preprint volume - SIBM

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PLANKTON COMMITEE
analysis were performed on a portion of isolated strains to evaluate diversity of the
luminous microbial communities.
Results - We refer about 421 seawater samples from 38 stations along 5 key sections
localized inside and on the board of the studied area. Along surveyed sections,
abundance values ranged from 0 to 21 (Section 1: Sardinia-Sicily), 0-68 (Sec. 2: Sicily-
Tunisia), 0-73 (Sec. 3: Sicily-Pantelleria-Tunisia), 0-117 (Sec. 4: Sicily-Malta-Libya)
and 0-28 (Sec. 5: Ionian Sea) CFU 100 ml -1 , respectively. LB showed a wide range of
values along the water column, whereas near the bottom they increased up to 117 CFU
100 ml -1 . Coastal samples near the bottom of Sicily Strait showed always the highest
counts. From plates, 384 strains of LB were isolated and 122 (31.7%) grown under
laboratory condition. ARDRA analysis, performed on 100 strains, showed 4 OTUs
(Operational Taxonomic Units) for each of two restriction enzymes employed (HHAI
and RSAI), according to previous research carried out in this area (De Luca et al.,
2007). Under the hydrological conditions, the area shows the typical 3-layer systems
characterized by Modified Atlantic Water (MAW) at the surface (37.7-37.8 psu), LIW
at intermediate depth (38.6-38.7 psu) and deep waters (tEMDW, TDW and WMDW)
that occupy the areas below LIW or mix with LIW at the entrance of the Tyrrhenian
Sea along western Sicilian coast.
Conclusions – The results obtained in this study were comparable with those
previously reported for other areas of the Mediterranean Sea; LB show a patchiness
distribution with an appreciable increase in viable counts generally observed near the
bottom. LB values in the seawater samples from the Sicily Strait were higher than in
the Tyrrhenian and Ionian samples and lower than in the Gibraltar Strait and Alboran
Sea, probably due to richness of nutrients and organic matter. The distribution pattern
of LB, as a function of depth and distance from the coast previously assumed for
several areas of Mediterranean Sea (De Luca et al., 2009), can be also confirmed for
this area.
Aknowledgements: A special thank to Captain Vincenzo Lubrano Lavadera of the R/V Urania vessel
and its crew and technicians onboard.
References
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comunità microbica luminosa nel Mar Mediterraneo Centro-Occidentale. 19° Congresso Ass.
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GENTILE G., DE LUCA M., DENARO R., LA CONO V., SMEDILE F., SCARFÌ S., DE
DOMENICO E., DE DOMENICO M., YAKIMOV M.M. (2009) - PCR-based detection of
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This work is funded by: Messina University (PRA 2004); EU IP-MyOcean project (contract FP7-
SPACE-2007-1) and EU IP-ECOOP project (contract 036355-2).
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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