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The Straits of Messina (Southern Italy, Mediterranean Sea) is a very complex area: it connects two basins (Tyrrhenian and Ionian) with different hydrographic features and is characterised by upwelling and mixing phenomena. The aim of the study was to evaluate if and how the physical and chemical water conditions and hydrodynamics influenced the phytoplankton and bacterial patterns and the functioning of this ecosystem. During a late winter survey, size-fractionated phytoplankton (from 0.2 to 200 ?m) biomass (chlorophyll a), cell densities and species composi-tion as well as total picoplankton abundances, morphotype composition and activity levels of the enzymes leucine aminopeptidase, ?-glucosidase and alkaline phosphatase were investigated. The obtained results showed a marked diversification among the water masses identified within the Straits area. The analyses of the phytoplankton diversity indices, and particularly those based on phylogenetic relationships between species (indices of taxonomic diversity and dis-tinctness), confirmed our findings. In conclusion, phytoplankton and bacterial communities pat-terns provide a suitable approach to evaluate how microbial communities respond to changing environmental scenarios. This tool could be applied to other temperate Mediterranean ecosystems.

Coastal marine ecosystems host complex microbial communities, and both continental inputs and water masses properties influence microbial composition and its metabolism. The identifying traits of the phytoplankton and bacteria such as biomass, size, shape and their metabolism related to organic matter production and degradation, recognized as indicators of the functioning of an ecosystem, were observed in the Gulf of Manfredonia in late spring. This Gulf area, located in the South Adriatic Sea, is characterized by terrestrial inputs and mesoscale circulation influence such as coastal waters flowing southward from the North Adriatic and off-shore waters interested by the Ionian Sea. Water samples were grouped in clusters (Coastal, Intermediate, Offshore and Deep Systems) according to the water column properties. Phytoplankton community biomass and composition, autotrophic and total prokaryotic abundances and microbial metabolism such as enzyme activity rates and prokaryotic heterotrophic production were analysed to elucidate the trophic pathways with the objective to infer on the ecosystem status. As expected, size-fractionated phytoplankton biomass and production, showed greater concentration in Coastal waters with prevalence of the largest fractions (micro- and nano-) supported by the diatoms. Conversely, lower biomass and production were measured in all off-shore waters, mainly sustained by smallest fractions (nano-sized phytoflagellates and picophytoplankton). Total and autotrophic prokaryotic abundance decreased from coastal to off-shore stations, inversely with respect to cell volume. Prokaryotic heterotrophic production was just below 50% compared to that of phytoplankton in all waters, evidencing an active biomass synthesis. High alkaline phosphatase and leucine aminopeptidase in Coastal and Offshore waters suggested the quick regeneration of Phosphorous and protein decomposition, respectively. Different levels of phytoplankton-bacteria association might provide a tool to define the ecological status of the studied system in the observed period, and a method of classification exportable to other coastal systems is proposed.

The effects of climate change-induced ice melting on the microbial communities in different glacial-fed aquatic systems have been reported, but seasonal dynamics remain poorly inves-tigated. In this study, the structural and functional traits of the aquatic microbial community were assessed along with the hydrological and biogeochemical variation patterns of the Arctic Pasvik River under riverine and brackish conditions at the beginning (May = Ice-melt(-)) and during the ice-melting season (July = Ice-melt(+)). The microbial abundance and morphometric analysis showed a spatial diversification between the riverine and brackish stations. Results highlighted different levels of microbial respiration and activities with different carbon and phosphorous utilization pathways, thus suggesting an active biogeochemical cycling along the river especially at the beginning of the ice-melting period. At Ice-melt(-), Gammaproteobacteria and Alphaproteobacteria were dominant in riverine and brackish stations, respectively. Conversely at Ice-melt(+), the microbial community composition was more homogeneously distributed along the river (Gammaproteobacteria>Alphaproteobacteria> Bacteroidetes). Our findings provide evidence on how riverine microbial communities adapt and respond to seasonal ice melting in glacial-fed aquatic ecosystems.

In order to understand bacterial-phytoplankton interactions in harbor environments, trophic conditions (nutrient, chlorophyll, organic matter), microbial enzyme activities and phytoplankton dynamics were studied seasonally from September 2018 to August 2019 in the Syracuse Gulf (Ionian Sea), a Mediterranean area subject to algal blooms. During spring, dinoflagellate bloom was coupled with high microbial activity rates; these actively recycled nutrients, sustaining phytoplankton growth.

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.

In the Kongsfjorden site (Svalbard Islands) glaciers retreat is one of the most evident signs of global warming. Such evidence has strong implications on the marine ecosystem. An oceanographic cruise was performed within the ARCA (ARctic: present Climatic change and pAst extreme events) Project in May 2016 to study the chemical-physical, biochemical and biological characteristics of superficial waters along a transect of 7 surface stations in inner Kongsfjorden until the Kronebreen glacier (stations 4-5-14-6-23-7 and 8, glacier). Station 4 was also sampled from surface to 100 m. The studied parameters were: temperature, salinity, dissolved oxygen, turbidity, nutrients, chlorophyll-a (Chl-a), Total Suspended Matter (TSM), chromophoric Dissolved Organic Matter (c-DOM) absorption, total bacterioplankton abundance and its respiring fraction, heterotrophic bacteria on Marine agar, extracellular enzymatic activity (leucine aminopeptidase - LAP, beta-glucosidase -GLU and alkaline phosphatase -AP). Temperature and salinity values decreased from station 4 to station 8 (near the glacier) and an opposite trend was observed for turbidity and nutrients values. TSM also peaked at station 8 while reduced concentrations of Chl-a characterized the surface waters. Ammonia, nitrite+nitrate and orthophosphate ranges were 0.45-1.44 µmol/l, 0.12-5.60 µmol/l, 0.10-0.48 µmol/l, respectively. CDOM absorption slope values (range 275-295 nm) varied from 0.0077 to 0.0109 nm-1. Total and respiring bacterioplankton counts were in the magnitude order of 106 and 104 cells/ml respectively and of 10^2 Colony Forming Units/ml. Enzymatic activity patterns were in the order AP>LAP>GLU, with rates lower than 1.78, 1.25 and 0.25 nmol respectively. Temperature affected negatively nutrients, TSM and turbidity, positively GLU. AP was associated to the heterotrophic bacteria (Pearson r=0.59). AP and c-DOM absorption spectra were significantly related (r=0.71), as well as LAP and Chl-a (r=0.97), suggesting fresh material stimulated enzymatic synthesis.

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.

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

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.

Total prokaryotic abundance, prokaryotic heterotrophic production and enzymatic activities were investigated in epi-, meso- and bathypelagic waters along a longitudinal transect covering the entire Mediterranean Sea. The prokaryotic production and enzymatic activities in deep waters were among the highest reported worldwide at similar depths, indicating that the peculiar physico-chemical characteristics of the Mediterranean Sea, characterized by warm temperatures (typically 13C also at abyssal depths), support high rates of organic carbon degradation and incorporation by prokaryotic assemblages. The higher trophic conditions in the epipelagic waters of the Western basin resulted in significantly higher prokaryotic production and enzymatic activities rates than in the Central-Eastern basin. While all of the variables decreased significantly from epi- to meso- and bathypelagic waters, cell-specific hydrolytic activity and cell-specific carbon production significantly increased. In addition, the deep-water layers were characterized by low half-saturation constants (Km) of all enzymatic activities. These findings suggest that prokaryotic assemblages inhabiting the dark portion of the Mediterranean Sea are able to channel degraded carbon into biomass in a very efficient way, and that prokaryotic assemblages of the deep Mediterranean waters work as a "bioreactor" of organic matter cycling. Since prokaryotic production and enzymatic activities in deep water masses were inversely related with oxygen concentration, we hypothesize a tight link between prokaryotic metabolism and oxygen consumption. As climate change is increasing deep-water temperatures, the predicted positive response of prokaryotic metabolism to temperature increases may accelerate oxygen depletion of deep Mediterranean waters, with cascade consequences on carbon cycling and biogeochemical processes on the entire deep basin.

The activity and abundance of microbial (eukaryotic phytoplankton and prokaryotic) community inhabiting the waters of the Manfredonia Gulf were studied to determine the possible effects played by the thermoaline gradient. Both the enzymatic hydrolysis and heterotrophic production processes showed the presence of three areas (coastal, off-shore, and transition) with different characteristics.

Large gradients of tidal displacements as well as topographic constrictions determine upwelling of deeper waters to the surface layer in the Straits of Messina. This work describes the seasonal variability of surface distribution of phytoplankton biomass depending on upwelling phenomena. Temperature, salinity, nitrates and phytoplankton fluorescence were measured in 1994 and 1995 by continuous underway surface real-time measurements on board dedicated research boats. Each survey was performed following the dynamic phases of flooding and ebbing tides. Large spatial gradients of physical-chemical and biological parameters were mainly found at low water slack, while at high water slack a diffused phytoplankton fluorescence was observed only in autumn, concurrent with the seasonal thermocline. Generally, during winter, the upwelling distribution was limited to narrow zones, while in summer it involved the middle of the Straits and southern zones. During spring in the southern zone of the Straits, maximum of chlorophyll-a fluorescence was detected (0.32 gl?1 Chl-a) in summer, when back and forth tidal movements become intense between the Tyrrhenian and the Ionian seas, values was everywhere lower. The Straits system can be compared to an "intermittent pump" which, during the different seasons, before enriched itself and then it provides nutrients to the surrounding basins.

The term Alternative Strategies refers to an updatable suite of options concerning policies, practices, and data requirements that would facilitate an application of the Systems Approach Framework (SAF) methodology, developed during the SPICOSA EU FP6 Integrated Project. The SPICOSA IP had the goal of developing the SAF for Coastal Zone applications in support of Sustainable Development in Coastal Areas and in the context of ICZM. This objective was accomplished through SAF applications in 18 Study Sites throughout the European Region. In addition to the SAF, the Project provided support for its development (supplementary information), archiving (model library and documentation), and dissemination (training and public outreach). The Alternative Strategies discussed herein represent an essential supplement to expedite and enrich SAF applications, which are designed to simulate an issue in a coastal zone system and provide quantitative and qualitative information on various scenarios concering the resolution of the Issue. The goal Alternative Strategies is to make readily accessable to potential SAF users, information regarding political strategies, technical options, and intelligent monitoring that can support the SAF simulation itself and enrich the quality of the simulation of the Policy Issue and enrich its associated scearions. As an example, a user starts by indentifying a critical policy issue and/or identifying an Impact in a Coastal Zone. The Alternative-Strategy database will quickly locate the key processes that influence the properties of the system and then suggest the right "set" of tools (political, technical and moinitoring) for the issue. This set can be used for all the four stages of the SAF, i.e. from the initial design phase of Issue/scenario identification until the final evaluation to the ouput phanse for the delivery of results concerning the requested management scenarios.

Il Golfo di Manfredonia è situato nel mare adriatico occidentale, sul litorale italiano che demarca la circolazione adriatica centrale da quella meridionale. Di seguito sono riportate le distribuzioni spaziali delle proprietà fisiche oceanografiche e della concentrazione di clorofilla-a nel Golfo di Manfredonia durante la stagione primaverile. Le caratteristiche generali della circolazione seguono la traccia della salinità, indicando che l’acqua con i valori alini elevati (S>38.65) risale nel centro del gyre dallo strato intermedio occupato dalla LIW. La distribuzione della concentrazione di Chl-a (all'interno di 0.05-0.55 mg Chl-a m-3) era governata dalle caratteristiche idrodinamiche osservate.

The aim of the study was to elucidate the microbial processes related to C and P biogeochemical cycles which occur at the surface layer (5-100 m) of the Ionian Sea during late autumn period. Two successive steps, concerning respectively the enzymatic hydrolysis of proteins, polysaccharides and organic phosphates and the incorporation of the released monomers into new microbial biomass were investigated, together with the abundance and biomass of total bacterioplankton and picophytoplankton and measurement of chlorophyll-a content as an index of phytoplankton biomass. Three main hydrological areas (Central Eastern -ICOr, Central- IC and Central-Western-Sicily Channel -ICOc-CS) with distinctive characteristics were identified by the analysis of 6 microbiological variables. ICOc-CS area was characterised by the highest values of microbial activity (production and decomposition) and consumption of inorganic phosphorus (Pi). IC area showed high potential mineralisation rates of organic phosphates and glycosides, while low total bacterioplankton and picophytoplankton abundances were found. In IC and ICOr areas, the high values of potentially mineralised Pi: consumed Pi ratio (59 and 250 respectively) provide the supply of Pi for further productive processes.

Le aree di transizione sono ambienti estremamente complessi e diversificati, la cui connotazione, oltre che dalla posizione intermedia fra il dominio marino e quello continentale, è definita da una elevata variabilità spaziale e/o temporale delle caratteristiche mesologiche, sedimentarie, trofiche ed ecologiche. Inoltre, la dinamicità dei processi trofici e della funzionalità del comparto primario, determinano, già nel breve-medio periodo, evidenti modificazioni nella composizione e struttura dei popolamenti planctonici e bentonici. L'insieme di queste caratteristiche fa sì che le Aree di Transizione siamo ambienti privilegiati per lo studio dei processi ambientali, in funzione della valenza diagnostica del monitoraggio integrato delle dinamiche evolutive di questi sistemi Sin dagli anni 70 il nostro gruppo di ricerca conduce, in varie aree di transizione della Sicilia, indagini a carattere ecosistemico, mirate alla definizione delle caratteristiche chimico-fisiche delle acque e dei sedimenti (serie temporali di T°C, salinità, ossigeno, tessitura dei sedimenti, ecc.), alla valutazione dello stato trofico (incidenza di Clorofilla, Carbonio organico ed inorganico, Produzione Primaria, Sali nutritivi, ecc.), nonché all'evoluzione spazio-temporale dei popolamenti microplanctonici, fitoplanctonici e bentonici. Il nostro interesse scientifico per gli ambienti di transizione, si è concretizzato nel corso dell'ultimo trentennio, in una serie di progetti interdisciplinari (Progetto Finalizzato Beni Culturali CNR, VECTOR, LOICZ-LaguNet: Italian Lagoon Observational Network, EU-Strategy: Harmful Algal Blooms Monitoring, ARPA- Monitoraggio dei corpi idrici superficiali della Regione Sicilia, ecc.), oltre che in una costante attività di interazione e collaborazione con le Amministrazioni Locali. Nel corso della pluriennale attività scientifica sono state affrontate diverse tematiche di ricerca, quali: Studio dei processi trofici, Effetti dell'inquinamento da idrocarburi sulle comunità bentoniche, Analisi dei fattori di alterazione ambientale, Fattori di stress e crisi distrofiche, Studio dei fenomeni HABs, Particellato sospeso e ruolo della CO2 , ecc.. Nell'ultimo decennio il nostro interesse scientifico è stato rivolto all'analisi comparata dei dati recenti con le serie storiche già acquisite, utilizzando il monitoraggio come chiave di lettura delle dinamiche evolutive dei sistemi di transizione, in funzione di una maggiore capacità di analisi e di interpretazione dei processi globali. Nei progetti attualmente in corso l'approccio ecosistemico di indagine è stato ulteriormente potenziato attraverso una maggiore integrazione con competenze scientifiche di altre sedi IAMC, da cui sono scaturite ipotesi percorribili per una futura programmazione scientifica integrata, finalizzata alla ricerca ed interpretazione di nuovi indici di valutazione ambientale, specifici per questi peculiari ambienti.

First estimations of microbial biomass and activities in the water column of the Tyrrhenian basin in association with the main Mediterranean water masses, are reported. Exponential decrease with depth of biomass and activities was registered assessing the predominant weight of export production in the basin and the scarce advection of preformed organic matter within the water masses. Important seasonal changing patterns occurred for respiration and primary production more than for biomass. The evaluation of the carbon budget by microbial community showed PP/R ratios close to 1 in July, and a clear productive metabolism in December.