The study of the impact of climate change on the environment has been based, until very recently, on an global approach, whose interest from a local point of view is very limited. This thesis, on the contrary, has treated the study of the impact of climate change in the Adriatic Sea basin following a twofold strategy of regionalization and integration of numerical models in order to reproduce the present and future scenarios of the system through a more and more realistic and solid approach. In particular the focus of the study was on the impact on the physical environment and on the sediment transport in the basin. This latter is a very new and original issue, to our knowledge still uninvestigated. The study case of the coastal area of Montenegro was particularly studied, since it is characterized by an important supply of sediment through the Buna/Bojana river, second most important in the Adriatic basin in terms of flow. To do this, a methodology to introduce the tidal processes in a baroclinic primitive equations Ocean General Circulation Model was applied and tidal processes were successfully reproduced in the Adriatic Sea, analyzing also the impacts they have on the mean general circulation, on salt and heat transport and on mixing and stratification of the water column in the different seasons of the year. The new hydrodynamical model has been further coupled with a wave model and with a river and sea sediment transport model, showing good results in the reproduction of sediment transport processes. Finally this complex coupled platform was integrated in the period 2001-2030 under the A1B scenario of IPCC, and the impact of climate change on the physical system and on sediment transport was preliminarily evaluated.

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The modern stratigraphy of clastic continental margins is the result of the interaction between several geological processes acting on different time scales, among which sea level oscillations, sediment supply fluctuations and local tectonics are the main mechanisms. During the past three years my PhD was focused on understanding the impact of each of these process in the deposition of the central and northern Adriatic sedimentary successions, with the aim of reconstructing and quantifying the Late Quaternary eustatic fluctuations. In the last few decades, several Authors tried to quantify past eustatic fluctuations through the analysis of direct sea level indicators, among which drowned barrier-island deposits or coral reefs, or indirect methods, such as Oxygen isotope ratios (δ18O) or modeling simulations. Sea level curves, obtained from direct sea level indicators, record a composite signal, formed by the contribution of the global eustatic change and regional factors, as tectonic processes or glacial-isostatic rebound effects: the eustatic signal has to be obtained by removing the contribution of these other mechanisms. To obtain the most realistic sea level reconstructions it is important to quantify the tectonic regime of the central Adriatic margin. This result has been achieved integrating a numerical approach with the analysis of high-resolution seismic profiles. In detail, the subsidence trend obtained from the geohistory analysis and the backstripping of the borehole PRAD1.2 (the borehole PRAD1.2 is a 71 m continuous borehole drilled in -185 m of water depth, south of the Mid Adriatic Deep - MAD - during the European Project PROMESS 1, Profile Across Mediterranean Sedimentary Systems, Part 1), has been confirmed by the analysis of lowstand paleoshorelines and by benthic foraminifera associations investigated through the borehole. This work showed an evolution from inner-shelf environment, during Marine Isotopic Stage (MIS) 10, to upper-slope conditions, during MIS 2. Once the tectonic regime of the central Adriatic margin has been constrained, it is possible to investigate the impact of sea level and sediment supply fluctuations on the deposition of the Late Pleistocene-Holocene transgressive deposits. The Adriatic transgressive record (TST - Transgressive Systems Tract) is formed by three correlative sedimentary bodies, deposited in less then 14 kyr since the Last Glacial Maximum (LGM); in particular: along the central Adriatic shelf and in the adjacent slope basin the TST is formed by marine units, while along the northern Adriatic shelf the TST is represented by costal deposits in a backstepping configuration. The central Adriatic margin, characterized by a thick transgressive sedimentary succession, is the ideal site to investigate the impact of late Pleistocene climatic and eustatic fluctuations, among which Meltwater Pulses 1A and 1B and the Younger Dryas cold event. The central Adriatic TST is formed by a tripartite deposit bounded by two regional unconformities. In particular, the middle TST unit includes two prograding wedges, deposited in the interval between the two Meltwater Pulse events, as highlighted by several 14C age estimates, and likely recorded the Younger Dryas cold interval. Modeling simulations, obtained with the two coupled models HydroTrend 3.0 and 2D-Sedflux 1.0C (developed by the Community Surface Dynamics Modeling System - CSDMS), integrated by the analysis of high resolution seismic profiles and core samples, indicate that: 1 - the prograding middle TST unit, deposited during the Younger Dryas, was formed as a consequence of an increase in sediment flux, likely connected to a decline in vegetation cover in the catchment area due to the establishment of sub glacial arid conditions; 2 - the two-stage prograding geometry was the consequence of a sea level still-stand (or possibly a fall) during the Younger Dryas event. The northern Adriatic margin, characterized by a broad and gentle shelf (350 km wide with a low angle plunge of 0.02° to the SE), is the ideal site to quantify the timing of each steps of the post LGM sea level rise. The modern shelf is characterized by sandy deposits of barrier-island systems in a backstepping configuration, showing younger ages at progressively shallower depths, which recorded the step-wise nature of the last sea level rise. The age-depth model, obtained by dated samples of basal peat layers, is in good agreement with previous published sea level curves, and highlights the post-glacial eustatic trend. The interval corresponding to the Younger Dyas cold reversal, instead, is more complex: two coeval coastal deposits characterize the northern Adriatic shelf at very different water depths. Several explanations and different models can be attempted to explain this conundrum, but the problem remains still unsolved.

L’unione di approcci differenti durante lo studio dei sistemi petroliferi, come l’accoppiamento dello studio delle emissioni in superficie con le analisi geochimiche e strutturali, è un aspetto principale nelle strategie di sviluppo per la ricerca degli idrocarburi. La presenza di acqua connata nelle sequenze sedimentarie profonde e la sua sovrappressione che viene generata dalle spesse coperture sedimentarie, incrementata inoltre dalla generazione di idrocarburi in profondità, sono fattori di controllo primari per la migrazione e l’emissione di fluidi in superficie. I risultati ottenuti da questo studio forniscono nuovi elementi per la comprensione del ruolo dello studio dei vulcani di fango nell’esplorazione petrolifera, e nuove importanti prove per la caratterizzazione dei sistemi petroliferi nelle aree considerate. / To join different approaches in the study of petroleum systems, as to couple the study of surface seeps with geochemical and structural analysis, is a leading aspect in a development strategy for hydrocarbons. The occurrence of pore water in the deep sedimentary successions and its overpressure due to the thick covering sequences, which is enhanced by the hydrocarbons generation at depth, are primary controls for the fluid migration and emission at the surface through the cold seeps. The results from this study provide new elements to understand the role of mud volcanoes study in the frame of petroleum exploration, and new important evidences for the petroleum systems in the areas considered.

Sea-level variability is characterized by multiple interacting factors described in the Fourth Assessment Report (Bindoff et al., 2007) of the Intergovernmental Panel on Climate Change (IPCC) that act over wide spectra of temporal and spatial scales. In Church et al. (2010) sea-level variability and changes are defined as manifestations of climate variability and change. The European Environmental Agency (EEA) defines sea level as one of most important indicators for monitoring climate change, as it integrates the response of different components of the Earths system and is also affected by anthropogenic contributions (EEA, 2011). The balance between the different sea-level contributions represents an important source of uncertainty, involving stochastic processes that are very difficult to describe and understand in detail, to the point that they are defined as an enigma in Munk (2002). Sea-level rate estimates are affected by all these uncertainties, in particular if we look at possible responses to sea-level contributions to future climate. At the regional scale, lateral fluxes also contribute to sea-level variability, adding complexity to sea-level dynamics. The research strategy adopted in this work to approach such an interesting and challenging topic has been to develop an objective methodology to study sea-level variability at different temporal and spatial scales, applicable in each part of the Mediterranean basin in particular, and in the global ocean in general, using all the best calibrated sources of data (for the Mediterranean): in-situ, remote-sensig and numerical models data. The global objective of this work was to achieve a deep understanding of all of the components of the sea-level signal contributing to sea-level variability, tendency and trend and to quantify them.

The thesis objectives are to develop new methodologies for study of the space and time variability of Italian upper ocean ecosystem through the combined use of multi-sensors satellite data and in situ observations and to identify the capability and limits of remote sensing observations to monitor the marine state at short and long time scales. Three oceanographic basins have been selected and subjected to different types of analyses. The first region is the Tyrrhenian Sea where a comparative analysis of altimetry and lagrangian measurements was carried out to study the surface circulation. The results allowed to deepen the knowledge of the Tyrrhenian Sea surface dynamics and its variability and to defined the limitations of satellite altimetry measurements to detect small scale marine circulation features. Channel of Sicily study aimed to identify the spatial-temporal variability of phytoplankton biomass and to understand the impact of the upper ocean circulation on the marine ecosystem. An combined analysis of the satellite of long term time series of chlorophyll, Sea Surface Temperature and Sea Level field data was applied. The results allowed to identify the key role of the Atlantic water inflow in modulating the seasonal variability of the phytoplankton biomass in the region. Finally, Italian coastal marine system was studied with the objective to explore the potential capability of Ocean Color data in detecting chlorophyll trend in coastal areas. The most appropriated methodology to detect long term environmental changes was defined through intercomparison of chlorophyll trends detected by in situ and satellite. Then, Italian coastal areas subject to eutrophication problems were identified. This work has demonstrated that satellites data constitute an unique opportunity to define the features and forcing influencing the upper ocean ecosystems dynamics and can be used also to monitor environmental variables capable of influencing phytoplankton productivity. / L'obiettivo di questa tesi è lo studio della variabilità spazio temporale dei parametri chiave (temperatura, clorofilla e correnti) che descrivono lo stato dell'ecosistema marino dei mari Italiani attraverso un uso integrato di dati satellitari multi sensore e osservazioni in situ. Diversi tipologie di approcci e differenti dataset sono stati utilizzati per studiare la circolazione marina, l'impatto dei forzanti fisici sulla variabilità della biomassa fitoplantonica, e per definire una possibile metodologia di utilizzo di dati satellitari per lo studio della qualità delle acque. Sono stati scelti tre sottobacini dei Mari italiani su cui effettuare differenti tipologie di analisi. L'analisi comparata di misure altimetriche e dati lagrangiani condotta nel Mar Tirreno ha permesso di ridisegnare la circolazione del bacino e di dimostrare la presenza di ricolazioni semipermantenti e di strutture transienti che dominano la dinamica di questo mare. Inoltre è stata evidenziata l'importanza dell'uso congiunto di dati altimetrici e lagrangiani per l'identificazioni di strutture della circolazione di piccola scala. Nel Canale di Sicilia sono state invece analizzate lunghe serie temporali di clorofilla, di temperatura superficiale del mare e livello del mare utilizzando tecniche statistiche avanzate. Lo studio ha permesso identificare la variabilità spazio-temporale del fitoplancton e di comprendere l'impatto della circolazione marina sull’ecosistema costiero siciliano. Infine sull’intero sistema marino costiero Italiano è stata sviluppata una procedura per la definizione di trend di clorofilla da dati di Ocean Color. Diversi metodi per la stima del trend sono stati testati sia su serie temporali di dati OC che su serie temporali di misure in situ di clorofilla effettuate dalle Agenzie Regionali per la Protezione ambientale. Il confronto tra le stime ottenute ha permesso di individuare il metodo che meglio si adatta ai dati satellitari. Tale metodo è stato poi applicato per identificare le aree costiere Italiane soggette ad eutrofizzazione.

Questa tesi di dottorato è inserita nell’ambito della convenzione tra ARPA_SIMC (che è l’Ente finanziatore), l’Agenzia Regionale di Protezione Civile ed il Dipartimento di Scienze della Terra e Geologico - Ambientali dell’Ateneo di Bologna. L’obiettivo principale è la determinazione di possibili soglie pluviometriche di innesco per i fenomeni franosi in Emilia Romagna che possano essere utilizzate come strumento di supporto previsionale in sala operativa di Protezione Civile. In un contesto geologico così complesso, un approccio empirico tradizionale non è sufficiente per discriminare in modo univoco tra eventi meteo innescanti e non, ed in generale la distribuzione dei dati appare troppo dispersa per poter tracciare una soglia statisticamente significativa. È stato quindi deciso di applicare il rigoroso approccio statistico Bayesiano, innovativo poiché calcola la probabilità di frana dato un certo evento di pioggia (P(A|B)) , considerando non solo le precipitazioni innescanti frane (quindi la probabilità condizionata di avere un certo evento di precipitazione data l’occorrenza di frana, P(B|A)), ma anche le precipitazioni non innescanti (quindi la probabilità a priori di un evento di pioggia, P(A)). L’approccio Bayesiano è stato applicato all’intervallo temporale compreso tra il 1939 ed il 2009. Le isolinee di probabilità ottenute minimizzano i falsi allarmi e sono facilmente implementabili in un sistema di allertamento regionale, ma possono presentare limiti previsionali per fenomeni non rappresentati nel dataset storico o che avvengono in condizioni anomale. Ne sono esempio le frane superficiali con evoluzione in debris flows, estremamente rare negli ultimi 70 anni, ma con frequenza recentemente in aumento. Si è cercato di affrontare questo problema testando la variabilità previsionale di alcuni modelli fisicamente basati appositamente sviluppati a questo scopo, tra cui X – SLIP (Montrasio et al., 1998), SHALSTAB (SHALlow STABility model, Montgomery & Dietrich, 1994), Iverson (2000), TRIGRS 1.0 (Baum et al., 2002), TRIGRS 2.0 (Baum et al., 2008). / This PhD thesis is inserted in the agreement between ARPA_SIMC (which is the sponsor), the Regional Civil Protection and the Department of Earth Sciences and Geo - Environmental of the University of Bologna. The main objective is the determination of possible rainfall thresholds for triggering landslides in Emilia Romagna, which can be used as an aid in forecasting operations of Civil Protection. In a such complex geological context, the distinction between critical and non-critical rainfall is not trivial: when different outputs (failure or no-failure) can be obtained for the same input (a given rainfall event) a deterministic approach is no longer applicable and a probabilistic model is needed. We use a Bayesian statistical approach, applied to a dataset ranging between 1939 and 2009, that is a direct application of conditional probabilities. The conditional probability is the probability of some event A (in our case a landslide) given the occurrence of some other event B (a rainfall episode with a certain magnitude, expressed in terms of total rainfall, intensity or any other variable). Conditional probability is written P(A|B) and it is read “the probability to have a landslide (A) given a rainfall episode (B)”. Probabilistic Bayesian thresholds minimize false alarms and can be easily implemented in a regional warning system, but their predictive capacity is limited about phenomena that are not represented in the historical dataset. This is the case of shallow landslides evolving in debris flows, extremely rare in the last 70 years, but, recently, their frequency is increasing. We tried to address this problem by testing the predictive capacity of some physically based models developed in literature, as X - SLIP (Montrasio et al., 1998), SHALSTAB (model Shallow Stability, Montgomery & Dietrich, 1994), Iverson (2000), TRIGRS 1.0 (Baum et al., 2002), TRIGRS 2.0 (Baum et al., 2008).

Nel Comune di Ravenna, oltre 6.800 ettari di terreni agricoli sono a rischio salinizzazione, a causa dell’alta salinità delle acque sotterranee presenti all’interno dell’acquifero freatico costiero. L'area è interessata da subsidenza naturale, per compattazione dei sedimenti alluvionali e antropica, causata dall’estrazione di gas e dall’eccessivo sfruttamento delle acque sotterranee. Ne deriva che la maggior parte di questo territorio è sotto il livello medio del mare e l'agricoltura, così come ogni altra attività umana, è possibile grazie ad una fitta rete di canali di drenaggio che garantiscono il franco di coltivazione. L’agricoltura è una risorsa importante per la zona, ma a causa della scarsa disponibilità di acque dolci e per l’aumento dei processi di salinizzazione dei suoli, necessita di un cambiamento. Servono pratiche agricole sostenibili, con idonei requisiti irrigui, di drenaggio del suolo, di resistenza alla salinizzazione e di controllo del suolo. Dopo un’analisi generale sulle condizioni dell’acquifero, è stato monitorato un transetto di 10km rappresentativo della parte costiera di Ravenna. Infine, con l'obiettivo di comprendere l'interazione tra un canale d'irrigazione e le acque sotterranee, una piccola area agricola (12 ettari), è stata monitorata nel corso del 2011 utilizzando metodi idrologici, geochimici e geofisici. I risultati di questo lavoro mostrano una diffusa salinizzazione della falda freatica, ma anche la presenza di una lente d'acqua dolce spessa 5m, a 400m dalla linea di riva, con caratteristiche chimiche (hydrofacies) tipici di acque continentali e con dimensioni variabili stagionalmente. Questa bolla di acqua dolce si è originata esclusivamente dalle infiltrazioni dal canale d’irrigazione presente, in quanto, il contributo dell’irrigazione superficiale è stato nullo. Sfruttando la rete di canali di drenaggio già presente sarebbe possibile estendere questo processo d’infiltrazione da canale in altre porzioni dell’acquifero allo scopo di ricaricare l’acquifero stesso e limitare la salinizzazione dei suoli. / In the municipality of Ravenna, more than 6800 hectares of farmland are at a risk for soil salinization, because of the high groundwater salinity in the coastal aquifer, which is widespread with the exception of some ephemeral freshwater lenses below the dune belts and in areas far from the land reclamation pumping stations. The area is affected by subsidence both natural due to compaction of alluvial sediments and anthropogenic caused by gas and groundwater over-exploitation. As a result, most of this territory is below mean sea level and agriculture as well as any other human activity is possible thanks to a dense network of drainage channels and land reclamation pumping stations. Agricultural activities in the area are an important asset for the local economy but they are challenged by scarce freshwater resources, water logging, and soil salinization. Sustainable agriculture practices need to address irrigation requirements, land drainage, and soil salinization control. With the aim to understand the interaction between irrigation channel and groundwater, a small agricultural area (12 hectares), was monitored during 2011 by using hydrological, geochemical and geophysical methods. The results of this work shows a widespread salinization of the phreatic aquifer but also the presence of a 4-meters-thick freshwater lens, at 400 meters from the shore line, with chemical characteristics (hydrofacies) typical of river water and that increases size in summer period. This fresh water lens has formed due to seepage from an irrigation channel into the aquifer. The contribution of irrigation water sprayed on top of the land to freshwater aquifer recharge is practically zero. By redesigning the network of irrigation channels to store excess river and irrigation water, the amount of freshwater infiltration into the aquifer could be increased and groundwater and soil salinization prevented.

The most ocean - atmosphere exchanges take place in polar environments due to the low temperatures which favor the absorption processes of atmospheric gases, in particular CO2. For this reason, the alterations of biogeochemical cycles in these areas can have a strong impact on the global climate. With the aim of contributing to the definition of the mechanisms regulating the biogeochemical fluxes we have analyzed the particles collected in the Ross Sea in different years (ROSSMIZE, BIOSESO 1 and 2, ROAVERRS and ABIOCLEAR projects) in two sites (mooring A and B). So it has been developed a more efficient method to prepare sediment trap samples for the analyses. We have also processed satellite data of sea ice, chlorophyll a and diatoms concentration. At both sites, in each year considered, there was a high seasonal and inter-annual variability of biogeochemical fluxes closely correlated with sea ice cover and primary productivity. The comparison between the samples collected at mooring A and B in 2008 highlighted the main differences between these two sites. Particle fluxes at Mooring A, located in a polynia area, are higher than mooring B ones and they happen about a month before. In the mooring B area it has been possible to correlate the particles fluxes to the ice concentration anomalies and with the atmospheric changes in response to El Niño Southern Oscillations. In 1996 and 1999, years subjected to La Niña, the concentrations of sea ice in this area have been less than in 1998, year subjected to El Niño. Inverse correlation was found for 2005 and 2008. In the mooring A area significant differences in mass and biogenic fluxes during 2005 and 2008 has been recorded. This allowed to underline the high variability of lateral advection processes and to connect them to the physical forcing. / Gli ambienti polari rappresentano il luogo in cui avvengono i maggiori scambi tra atmosfera e oceano grazie alle basse temperature che favoriscono i processi di assorbimento dei gas atmosferici, in particolare di CO2. Le alterazioni dei cicli biogeochimici di queste regioni quindi possono avere un forte impatto sul clima globale. Ci si è proposti di contribuire alla definizione dei meccanismi che regolano attualmente i flussi biogeochimici nel Mare di Ross analizzando il particellato raccolto in vari anni (progetti ROSSMIZE, BIOSESO 1 e 2, ROAVERRS e ABIOCLEAR) in due siti fissi (mooring A e B). A tal fine è stato messo a punto un metodo di preparazione dei campioni di trappola più efficiente e sono stati elaborati i dati da satellite relativi alla concentrazione dei ghiacci, di clorofilla a e di diatomee. In ognuno degli anni esaminati, in entrambi i siti, si è osservata un’alta variabilità stagionale e interannuale dei flussi biogeochimici strettamente correlata alla copertura di ghiaccio e alla produttività primaria. Il confronto tra i campioni del 2008 raccolti dai mooring A e B ha evidenziato le principali differenze tra i due siti: nel mooring A, situato nell’area di polynia, flussi più alti e anticipati di circa un mese rispetto al mooring B. Nella zona del mooring B i flussi di particelle sono stati correlati alle fluttuazioni dei ghiacci e alle variazioni atmosferiche dovute a El Niño Southern Oscillation. Nel 1996 e 1999, anni soggetti a La Niña, le concentrazioni dei ghiacci sono state minori mentre nel 1998, periodo soggetto a El Niño, maggiori. Correlazione inversa è stata riscontrata per il 2005 e il 2008. Nell’area del mooring A le consistenti differenze registrate nei flussi relativi al 2005 e 2008, hanno consentito di evidenziare l’alta variabilità dei fenomeni di avvezione laterale e di collegarli al forcing fisico.