Search

The Eastern Mediterranean Transient (EMT) lasted from the late-1980s to the mid-1990s and appears as the major climatic perturbation of circulation and water mass properties of the Mediterranean in the past hundred years. About 20% of the waters below 1200 m depth horizon werere placed in the eastern Mediterranean Sea by younger waters of Aegean origin with an average formation rate (1.2 Sv) four times faster than the rate calculated for the Adriatic source waters before the occurrence of EMT. The consequences of the EMT continue also today and have spread in the Western Mediterranean basin. A variety of altered biological processes have been recorded in the pelagic realm of the Mediterranean Sea after the 'EMT' onset and this review discusses them critically and relates the triggering of these climatic phenomena in the future with the possible impacts on the marine biota.

Il CNR di Messina svolge ricerche di carattere microbiologico in aree polari, con particolare focus sulle aree marine antartiche e periantartiche, dal 1988. Dal 2009 partecipa anche a diverse spedizioni in aree polari artiche, comprese le Isole Svalbard. In queste ultime, le ricerche del gruppo sono state condotte nel Kongsfjorden nell'ambito di tre progetti: PolyArc, MYKA e ARCA. La comunità microbica marina gioca un ruolo chiave nella rete trofica artica, in quanto controlla diversi processi, fra cui la produzione primaria, il turnover degli elementi biogenici, la degradazione della materia organica e la mineralizzazione di xenobiotici e inquinanti. In questo contesto diversi sono stati gli approcci metodologici e le strategie di campionamento adottate su campo nel Kongsfjorden dal gruppo di ricerca, in funzione anche della logistica e delle risorse disponibili. I molteplici studi condotti hanno avuto carattere multidisciplinare, e rivolti 1) allo studio della struttura della comunità batterica nei sedimenti e nell'acqua (in collaborazione con l'Università di Messina), 2) alla valutazione nel breve periodo dei trends biogeochimici e microbici lungo la colonna d'acqua (in collaborazione con l'Università di Rio de Janeiro e Miserocchi S., ISMAR di Bologna), 3) all'isolamento di batteri potenzialmente degradanti inquinanti come PCB (Giannarelli S., Università di Pisa) e PAH, 4) alla valutazione di bloom fitoplanctonici e al rilevamento di specie potenzialmente tossiche (in collaborazione con Caroppo C., IRSA di Taranto), e 5) alla valutazione della componente microbica (attività, funzioni e composizione) in un'area prossima ai ghiacciai, grazie all'applicazione su campo di un multi campionatore di acqua, prodotto in collaborazione con i colleghi del CNR dell'INM (Caccia M., Bruzzone G.) che hanno sperimentato diversi Autonomous Underwater Vehicles (AUVs). Quest'ultima tematica di ricerca costituisce sicuramente un challenge per studi futuri in quanto consente di acquisire dati ambientali e biologiciin siti inaccessibili all'uomo per problemi legati alla logistica e al campionamento in sicurezza.

Harbors are enclosed coastal sites particularly vulnerable to anthropogenic-derived pressure with an important role for human society but with impacts on marine environments. While the chemical pollutants present in the ports are still known, little is known about the presence of bacterial pathogens, as descriptor of water quality and it is not clear whether these areas, that are subjected to anthropogenic pressure, can be considered as potential reservoirs for antibiotic resistant bacteria. In this context our research was focused on Messina harbor. The harbor is one of the main tourist settlements in the Mediterranean Sea and a big commercial traffic also. The aim of this study was to assess the distribution of potentially pathogenic bacteria and their profiles of antibiotic susceptibility within the Messina harbor, and to analyze the results also in relation with the main hydrological characteristics of the area. Results showed that the bacterial isolates a part of the bacterial population present in marine aquatic environments is resistant or multi-resistant to various antibiotics. This result could be linked to the fact that the Messina harbor is a commercial site and is located in a highly urbanized area. In this study case, as far as faecal pollution is concerned, the values obtained for the faecal indicators show that the examined area is not affected by an anthropic impact; also there are no particular risks related to the presence of potentially pathogenic bacteria such halophilic vibrios.

A steam plant layout for the Waste Heat Recovery (WHR) of a marine four-stroke Dual Fuel (DF) engine is analysed by numerical simulation. The different values of exhaust gas mass flow and temperature between the two fuel modes involve different Rankine cycle thermodynamic characteristics, and therefore different heat exchangers sizes in order to obtain the greater waste heath recovery from the engine in both its operating modes. The two developed WHR solutions, optimized for each fuel type, are compared for the normal working conditions of the engine. In particular, the comparison is focused on the maximum plant efficiency and on the size and weight of the Heat Recovery Steam Generator (HRSG) components. Finally the best WHR compromise solution is indicated and tested for different load conditions and fuel types of the considered DF engine.

L'attività di ricerca si inserisce all'interno del Progetto Dispositivi ad Alto Contenuto Tecnologico per il Settore Biomedicale (DIATEME). Nell'obiettivo realizzativo 2 Sviluppo di dispositivi a funzionalità programmata nell'ambito dell'attività 1.2.2 sono stati sviluppati materiali antimicrobici a base di PVC ftalati free miscelati con zeoliti o nano particelle d'argento allo stato fuso. I compositi ottenuti sono stati caratterizzati tramite TGA ed analisi reologica. L'effetto antibatterico dei compositi è stato esaminato su Escherichia coli e Staphylococcus epidermidis in trypticase soia brodo (TSB). Per determinare il rilascio di ioni d'argento sono stati eseguiti due tipi di esperimenti che hanno consentito di determinare la quantità totale di ioni argento liberi rilasciati dai compositi giornaliero e dopo 5-10-20 giorni di accumulo tramite ICP-MS.

The microbial assemblage plays a key role in the coastal and pelagic food web of the Ross Sea; it controls many processes, including primary production, turnover of biogenic elements, degradation of organic matter and mineralization of xenobiotics and pollutants. Prokaryotic abundance and activity shift significantly over the annual cycle as sea ice melts and phytoplankton blooms develop. Marine microbs in the Ross Sea exibit a diversity which also depends on the timing, location and sampling method; research devoted to this group is increasing, using also genetic and molecular approaches in surface and deep waters. Our contribution will focus on the presentation of microbial data (standing stock and activity, as well as diversity and biotechnological potentialities of bacterial isolates) collected in the Ross Sea (coastal and pelagic) from 1988 to 2016, in the framework of the Italian National Programme for Antarctic Research (PNRA). Particular emphasis will be given to the interannual and decadal variability of microbial community in coastal and pelagic zones of the Ross Sea.

Microbiological controls of coastal seawaters are a common practice to verify their safety for human recreational and productive uses. The aim of the present study is to describe the microbiological conditions of the Castellammare Gulf (Trapani, Sicily), an area traditionally used for aquaculture purposes. Particularly, the results obtained from three surveys (1993-1995, 2000-2001 and 2007) are compared in order to depict how the hygienic-sanitary conditions of this marine ecosystem have evolved over time. Attention has been given to the abundance and distribution of the bacterial indicators of faecal pollution (faecal coliforms, enterococci and Salmonella spp.) as well as halophilic vibrios, using the culture methods conventionally indicated by current legislation in force for the sanitary control of waters designed for aquaculture productions. The obtained results shows that the sanitary conditions of seawater samples met the criteria recommended by current legislations for shellfish farming approved areas. The low concentrations of faecal pollution indicators and of halophilic vibrios confirm the general suitability of the Gulf of Castellammare for seafood production. Nevertheless, the detection of low percentages of potentially pathogenic species of halophilic vibrios stresses the importance of extending microbiological controls also to these emerging pathogens.

Recent climate changes in Arctic regions have caused retreat of glaciers, increases in meltwater outflow and massive inputs of suspended sediment load to the coastal marine environment (Malone et al., 2016). Moreover, climate warming in the Arctic can potentially affect large-scale microbial processes including population dynamics and trophic level interactions. Viral, prokaryotic and phytoplanktonic communities play a key role in relevant processes such as carbon fluxes and nutrient regeneration and can be viewed both as sentinels and amplifiers of global change. Monitoring of environmental changes, especially those related to ice melting, requires the availability of advanced technologies, able to promptly record phenomena occurring at different spatial and time scales. Moreover, the development of new sampling technology in extreme environments can be used in areas not reachable by vessels or subject to oil spill. In the context of ARCA project the main aims of our research unit were: i) to assess the variability of planktonic abundance and activities over short time scales in a site of the study area; ii) to design and built an automatic sampler for extreme polar environments; iii) to search for cold-adapted OIL/PAH(Polycyclic aromatic hydrocarbons)-degrading bacteria in the Arctic region.

Knowledge of microbial metabolism in the Mediterranean Sea is still limited or absent. During 12 cruises carried out in the Ionian Sea and Central Mediterranean Sea from 1998 to 2012, different biochemical and microbial parameters involved in the Carbon cycle were measured, to check the changes in microbial transformation of organic matter in different seasons. It is assumed that the microbial community (both auto- and heterotrophic) plays a key role in oligotrophic environments, cycling the elements within the microbial loop. Bacterial Growth Efficiency was also calculated from prokaryotic production and respiration. The aim of our study is to identify the microbial key components which could explain the biogeochemical variability in the euphotic layer, following their evolution on seasonal and inter-annual scales. Inter-annual temperature were comprised between 14.96 °C (s.d. ±0.08) and 20.52 °C (±3.32) and showed greater differences between cold (winter -spring) and warm (summer -autumn) periods. Inter-annual differences were also found among all the summer periods. With respect to seasonal differences, only winter and summer groups differed significantly. During summer, prokaryotic abundance and T, as well as enzymatic activities, were important factors that contributed to the observed variability.

With the aims to assess the microbial biogeochemistry in SES and to understand its connection with natural and/or anthropogenic pressures, the microbial signatures (biomass and metabolic rates) were analyzed in the Ionian-Adriatic system. Prokaryotes underwent fast modification of structure and metabolism within the water masses

Size is a key phenotypic trait of microbes that affects cell physiology and trophic interactions. In fact, size and shape of a cell affect the efficiency of nutrient uptake by determining the ratio of surface area to volume. Size-dependent mortality of marine prokaryotes contributes to the structuring of microbial assemblages since large cells are selectively grazed more than too small cells as well as too large cells cannot be ingested by protists. Moreover small cells may also be less susceptible to viral lysis. Finally, in combination with abundance quantification, the measurement of cell size and shape of prokaryotes of different populations is a prerequisite for obtaining a more detailed picture of biomass, production and carbon fluxes in microbial food webs. In spite of its importance, the biovolume of cells in microbial communities has not been extensively examined, although some data indicate that size varies among seasons and geographic locations due to variation in environmental conditions. Relatively few studies have so far dealt with prokaryotic size and shape in relation with environmental parameters and even a lower number has considered whether these parameters vary in relationship with different water bodies. In this context, this is the first study of prokaryotic size and shape distribution performed in the Sicily Channel with the aim of monitoring their phenotypic variability in different seasons. Seawater samples were collected during two oceanographic cruises in the frame of RITMARE Project, in Summer 2012 and Winter 2013. The variability of bacterial cell sizes and morphotypes was investigated - by using image analysis.

The trophic structure and related indices were investigated to assess the microplankton functionality in Engraulis encrasicolus (Chordata: Actinopterygii, Clupeiformes) spawning area of the Sicilian Channel. The integrated analysis of trophic parameters and correlated indices (C/N, N/P, POC/LAP+?GLU, POC/Chl-a) highlighted both the heterogeneity and the dynamism of the planktonic communities.

With the aim of providing an ecosystem approach to fisheries management, the monitoring of biological and environmental information was carried out during two oceanographic cruises (BANSIC 2012-13) performed in the Sicilian Channel in different seasonal conditions. The Sicilian Channel is a spawning area for the Engraulis encrasicolus (Linnaeus, 1758), a small pelagic species of commercial interest. The prokaryotic abundance and biomass as well as their hydrolysis rates on organic matter were investigated at selected stations in the euphotic layer. The particulate organic carbon (POC) was generally low (68-70 µgL-1 in summer), as well as those of particulate nitrogen (PN), reflecting a pattern typical of oligotrophic areas. The prokaryotic abundance ranged between 1.0 and 1.9 x106 cell ml-1 in summer and 2.5 - 8.1 x 105 cell ml-1 in winter. The prokaryotic biomass varied from 24.9 to 113.0 µgCL-1 in summer and 0.038-0.71 µgCL-1 in winter. Total leucine aminopeptidase showed the highest rates, followed by alkaline phosphatase and beta-glucosidase in summer. During winter 2013 the alkaline phosphatase prevailed on aminopeptidase, potentially releasing 346-739 ngPL-1 for new production. The potential release of carbon ranged between 230 and 407 ngCL-1 in summer, while in winter it was 88 -158 ngCL-1. The contribution of dissolved enzymatic activities varied between the two years, accounting for 21-42% of released total carbon. The rates of total hydrolysis were comparable to previous data obtained from other oligotrophic Ionian and Mediterranean areas, while this study was the first report about the dissolved enzymatic fraction in the Strait of Sicily.

Poly(vinyl chloride) (PVC) composites containing increasing amounts (2-20%, w/w) of silver zeolite (SZ) were prepared by melt mixing and characterized by thermal, mechanical and rheological analyses. The addition of large amount of SZ did not influence the processability and the formability of the composites, if compared to neat plasticized PVC. The antibacterial activity of PVC SZ composites was tested on Escherichia coli and Staphylococcus epidermidis and resulted promising both in culture broth and on agar plate and also in sterile urine seeded with these strains, for simulation purposes.