Search

A marine sediment core from the western Mediterranean provides a new highresolution 4,500-year record of palaeomagnetic secular variation and relative palaeointensity. In 2013, the 7.1-metre C5 core was recovered from the Tyrrhenian Sea as part of the NextData climate data project. The coring site, 15 km offshore from the Volturno river mouth, is well-located to record combined marine and terrestrial palaeoclimatic influences, and the fine-grained, rapidly deposited sediments are effective palaeomagnetic recorders. We investigate the palaeomagnetic field direction ACCEPTED MANUSCRIPT Downloaded from http://sp.lyellcollection.org/ at Universita Napoli Federico II on June 8, 2020 and strength recorded in the core, which provide a valuable high-resolution record of Holocene geomagnetic variation in the area. Using rock magnetic techniques, we constrain the magnetic mineralogy of the studied sediments and confirm their suitability for palaeomagnetic analysis. Palaeomagnetic declination and inclination records were determined by stepwise alternating-field demagnetization, and relative palaeointensity estimates were obtained based on normalization to anhysterestic and isothermal remanent magnetization and to magnetic susceptibility. The age of the core is wellconstrained with a tephro- and biostratigraphic age model, and its magnetic records are compared with relevant core and model data for the region, demonstrating that our record is compatible with previous results from the area. An automated curve matching approach is applied to assess the compatibility of our data with the existing secular variation path for the Mediterranean area

This paper examines downhole measurement inaccuracy with respect to the sampling interval by utilizing theoretical simulation and experimental data collected during the Seismic Microzonation study in Central Italy. Numerical simulation concerning the expected experimental data shows that the percent uncertainty relative to measured P-wave velocity (Vp) values increases with increasing sampling intervals of seismometric measure and Vp values and decreases with depth. In particular, setting Vp = 4000 m/s and by varying the sampling interval in the range (0.125, 0.250, 0.500 ms), the uncertainty reaches 40% at 2 m of depth for dt = 0.50 ms. When dt = 0.125 ms, the uncertainty decreases to 10%. A general equation relating uncertainty on Vp measurements with the actual layer velocity, allowed to derive ambiguity on the first break time, the source-sensor distance and the depth. Experimental data confirmed validity of this equation and put in evidence the effect of measurements sampling interval on the resolving power of DH measurements.

This paper describes the results of the activities performed during the project PONa3_00363 I-AMICA (High Technology Infrastructure for Climate and Environment Monitoring; www.i-amica.it), as part of the activities of Development Objective 4.4 (Processes of the biosphere-hydrosphere interface and features of coastal ecosystems). Through the strengthening of scientific-technological infrastructure and equipment, I-AMICA was planned to increase the observational capacity of the monitoring of marine coastal ecosystems, particularly vulnerable in the sensitive Mediterranean area and strictly connected to the natural and anthropic continental system. For this reason research activities were mainly focused on the neritic environment adjacent to the shelf area of the Volturno River mouth (Gulf of Gaeta - central part of the Tyrrhenian Sea). Advanced knowledge on the dynamics in time of marine coastal ecosystems, in relation to the physical, chemical and biological processes that characterize their habitat, were acquired while new methods of integrated monitoring, in relation to the specific characteristics of the study area, were tested. Particular attention was given to the identification of bio-indicators in water column and sediment at sea floor. The monitoring was also integrated by studies on the shoreline changes, seismic stratigraphy of deltaic deposits and by sedimentology and morpho-bathymetry of the seabed., Vengono presentati i risultati dell’attività di monitoraggio svolta nel corso del progetto PONa3_00363 I-AMICA (Infrastruttura di Alta tecnologia per il Monitoraggio Integrato Climatico-Ambientale; www.i-amica.it/i-amica/), nell’ambito delle attività relative all’Obiettivo Realizzativo 4.4 (Processi di interfaccia biosfera-idrosfera e funzionalità degli ecosistemi costieri). L’attività, che ha avuto come scopo l’acquisizione di conoscenze avanzate sulle dinamiche e/o variazioni nel tempo degli ecosistemi marino-costieri in relazione ai processi fisici, chimici e biologici che caratterizzano il loro habitat, si è sviluppata attraverso la sperimentazione di nuove metodologie di monitoraggio in relazione alle specifiche caratteristiche dell’area marino-costiera prospiciente la foce del fiume Volturno (Golfo di Gaeta). In particolare, oltre che sulle tecniche di monitoraggio classiche, lo studio si è principalmente focalizzato sulla acquisizione ed interpretazione di dati ambientali sia in colonna d’acqua che nei sedimenti a fondo mare e sulla identificazione di specie e/o associazioni di specie significative (bio-indicatori) da un punto di vista ambientale ed indicative dello stato di salute del sistema costiero. Poiché il sistema costiero rappresenta una struttura naturale complessa e delicata, la cui evoluzione è il risultato di delicati equilibri fisici, chimici e biologici, fortemente condizionabili dagli interventi antropici, l’attività di monitoraggio è stata integrata da studi sulla variazione della linea di costa, da studi sismostratigrafici della piana deltizia, sedimentologici e morfo-batimetrici dei fondali.

A new high resolution pollen, planktonic foraminiferal and oxygen isotopes record from a shallow water marine sedimentary core from the central Tyrrhenian Sea (Gulf of Gaeta) provides information on vegetation and climate changes occurred in the central Mediterranean region during the last 5000 cal. years BP (Margaritelli et al., 2016). Nine time intervals characterized by clear vegetation and climate changes and associated with archaeological/cultural periods have been described: Eneolithic (ca. 3080- ca. 2410 BC), Early Bronze Age (ca. 2410 BC–ca. 1900 BC), Middle Bronze Age-Iron Age (ca. 1900 BC–ca. 500 BC), Roman Period (ca. 500 BC–ca. 550 AD), Dark Age (ca. 550 AD–ca. 860 AD), Medieval Climate Anomaly (ca. 860 AD–ca. 1250 AD), Little Ice Age (ca. 1250 AD–ca. 1850 AD), Industrial Period (ca. 1850 AD–ca. 1950 AD), Modern Warm Period (ca. 1950 AD–present day). In this paper we aim to characterize the major vegetation changes influenced by climate and human impact.

A common problem of coastal aquifers is saltwater intrusion, induced by the flow of seawater into freshwater aquifers due to the groundwater development near the coast. Several factors affect the ingression of sea water. Among these, the most important are the coastal subsidence, the lowering of the sea level, coastal erosion and excessive pumping of groundwater. In fact, where the groundwater is pumped from coastal aquifers, the induced gradients may cause the migration of salt water from the sea to the well, making the freshwater unusable; being the fresh water less dense than salt water, it floats on top. According to the Integrated Coastal Zone Management (ICZM) of the European Commission, coastal areas are of great environmental, economic, social and cultural relevance. Therefore, the implementation of suitable monitoring and protection actions is fundamental for their preservation and for assuring the future use of this resource. Such actions have to be based on an ecosystem perspective for preserving coastal environment integrity and functioning and for planning sustainable resource management of both the marine and terrestrial components. Planning and management of natural resources through a dynamic process has to set, as its objective, the promotion of economic and social welfare of coastal zones. Unfortunately coastal plains are often contaminated by sea water intrusion, and the vulnerability to salinization is probably the most common and diffused problem in an aquifer. The boundary between salt water and fresh water is not distinct; the dispersion and transition zone, or salt-water interface are brackish with salt water and fresh water mixing. Under normal conditions fresh water flows from inland aquifers and recharge areas to coastal discharge areas to the sea. In general, groundwater flows from areas with higher groundwater levels (hydraulic head) to areas with lower groundwater levels. This natural movement of fresh water towards the sea prevents salt water from entering freshwater coastal aquifers (Barlow, 2003). Sea water intrusion in the water table can cause significant worsening in vegetation status. A likely related soil salinization would cause detrimental environmental and socioeconomic impacts. Hence, monitoring the sea water intrusion represents a priority for the safeguard of coastal areas. Identify changes in the freshwater-saltwater interface position can be a useful element for the rationalization of water resources and to guide the choice of use of these areas. Among the geophysical method applied for the location and movement of saltwater intrusion, best results were obtained by electrical methods (Al-Sayed and Al-Quady, 2007; Chitea et al., 2011). Many hydrological processes can be expected to provide significant contrasts in resistivity, consequently, Electrical Resistivity Tomography (ERT) has been adopted as a tool for new research within the hydrology field. Previous workers have demonstrated the ability of ERT to visualize hydrological structure within laboratory cores (Binley et al., 1996a, 1996b), monitor fluid or contaminant migration at the field scale (Daily et al., 1992, 1995; Schima et al., 1993), and to ascertain the efficiency of new contaminant remediation processes (Daily and Ramirez, 1995; LaBrecque et al., 1996). This paper outlines the results of a 3D ERT experiment obtained in the coastal alluvial plain of the Volturno river to assess changes in the freshwater-brine interface. The main aim was to investigate spatial and temporal variations of groundwater salinity. Acquisitions have been carried out in the months of May and October 2013 and in May 2014. This acquisition has allowed to obtain a monitoring 4D salt wedge in a "volume" specific subsurface.

Le zone di transizione marino-costiere, le aree alluvionali o vulcaniche sono generalmente caratterizzate dalla presenza di terreni sciolti e forti variazioni geometriche latero-verticali, che si ripercuotono sul campo di velocità del sottosuolo in questi casi estremamente variabile. La tomografia sismica multicanale a rifrazione è una tecnica di prospezione sismica che permette di definire un modello bi-dimensionale del sottosuolo, grazie l'individuazione delle anomalie di velocità di propagazione delle onde sismiche. Questa metodologia possiede un potere risolutivo nettamente superiore agli altri metodi convenzionali a rifrazione (es: Metodo Reciproco Generalizzato (GRM), metodo del tempo di ritardo (delay time), metodo del tempo intercetto), i quali si basano su un modello di sottosuolo costituito da strati regolari e con proprietà elastiche costanti, e che di conseguenza risultano inadeguati quando si è in presenza di forti variazioni laterali della velocità o inversioni di velocità con l'aumentare della profondità, cioè in presenza di situazioni geologicamente complesse. Il metodo sismico multicanale a rifrazione, grazie alla sua versatilità, è uno dei metodi geofisici più comunemente utilizzati per l'esplorazione del sottosuolo. Tale tecnica permette, infatti, di ricostruire in maniera dettagliata le morfologie sepolte e definire la presenza di eventuali discontinuità in sottosuolo (faglie, fratture). La tomografia sismica viene ampiamente adoperata a terra a scopi ingegneristici; invece in mare ha un'applicazione limitata, in particolare nelle zone costiere e di transizione come porti, lagune e baie. Recentemente, è stato dimostrato che le indagini sismiche a rifrazione in ambiente marino superficiale, possono fornire contributi importanti per la caratterizzazione degli strati del sottosuolo in termini di spessore e di velocità delle onde compressive VP (Whiteley&Stewart, 2008). La velocità delle onde P, infatti, è legata alla rigidità dei materiali e costituisce, quindi, un parametro importante per individuare il bedrock sismico ed i rapporti stratigrafici tra questo ed i sedimenti di copertura. La ricostruzione accurata del tetto della morfologia del bedrock sismico e quindi la valutazione della variazione degli spessori delle unità più superficiali è indispensabile nei progetti inerenti lo sviluppo di un'area portuale come ad esempio la costruzione di ponti o banchine e soprattutto nella stima degli interventi di dragaggio e ripascimento (MacGergor et al., 1994, Young Ho Cha et al., 2003). Al fine di dimensionare un intervento di dragaggio da eseguirsi nello specchio d'acqua del "Porticciolo della Tonnara" di Capo Granitola, a Campobello di Mazara (TP), l'Istituto per l'Ambiente Marino Costiero del CNR di Napoli ha eseguito un test di sismica marina multicanale a rifrazione. Sono stati realizzati 4 profili sismici, di cui tre seriati e paralleli alla costa ed incrociati da un quarto profilo, al fine di ottenere dati di tomografia sismica da elaborare mediante tecniche 2D e 3D. L'indagine ha interessato la fascia batimetrica compresa tra -1 e -3 metri e ha previsto il posizionamento di un cavo idrofonico d'acquisizione (bay-cable) direttamente sul fondale del porticciolo allo scopo di elaborare modelli di velocità bidimensionale delle onde P ed S.

Planktonic foraminiferal assemblages were studied at high-resolution in core KC01B from the Ionian Sea. Quantitative analysis allowed us to distinguish the main climatic features and associated paleoceanographic changes, that occurred between Marine Isotopic Stages (MIS) 13 and 9 (~ 500-300 ka). MIS 12 and MIS 10 are characterized by relatively temperate conditions and an oligotrophic oceanographic regime in the early part and by colder conditions and nutrient supply in the sub- surface water masses in the upper part. During these intervals, small but distinct peaks of Neogloboquadrina pachyderma sinistral (sin) are detected at times of extremely negative values of the planktonic foraminifera paleoclimatic curve. Their co-occurrence with similar episodes in the Atlantic suggests that the climate in the Central Mediterranean was associated with north-Atlantic millennial-scale climate instability. MIS 11 and MIS 9 are dominated by surficial warm-water taxa. The climate optimum is reached in the middle part of each of these stages, as denoted by the ACCEPTED MANUSCRIPT presence of Globigerinoides sacculifer, and persists for approximately 20 and 6 ka during MIS 11 and MIS 9 respectively. This warming is not constant but is characterized by three distinct intervals with elevated winter temperatures and/or weak winter mixing. Distribution of Globigerina bulloides, Turborotalita quinqueloba and Neogloboquadrina pachyderma dextral (dex) indicates that significant environmental changes occur across the transitions from glacial to interglacial MIS 12/MIS 11 (Termination V) and MIS 10/MIS 9 (Termination IV). The studied record documents a close linkage between Mediterranean climate evolution and higher- and lower-latitude climate change throughout MIS 13-9.

Uno studio ad alta risoluzione eseguito su depositi marini tardo olocenici carotati sul margine orientale del Mar Tirreno ha permesso l’individuazione attraverso lo studio di serie storiche di cicli sub-millenari legati alle variazioni dell’attività solare. Il confronto tra le serie temporali di Globorotalia inflata, di Total Solar Irradiance (TSI) e di ”14C, mostra una forte similarità in termini di fluttuazioni nel tempo. In particolare, i classici periodi freddi registrati nell’emisfero settentrionale (Dalton, Maunder, Spörer e Wolf) e associati a diminuzione dell’attività solare corrispondono a valori alti in % di G. inflata e viceversa. Inoltre, attraverso sofisticate analisi statistiche condotte su i diversi proxy sono state individuate periodicità di ~200 anni (cicli di Suess) e di ~500 anni attribuibili alle variazioni dell’attività solare. Questo dato supporta l’ipotesi che fluttuazioni centenarie dell’intensità solare hanno un controllo primario sulla distribuzione temporale delle associazioni a foraminiferi planctonci del Mediterraneo.

Vengono illustrati in questa nota alcuni risultati preliminari della crociera oceanografica condotta dall'Istituto di Ricerca Geomare Sud del CNR di Napoli a bordo della N/O Urania nell'agosto 1994. Questa indagine, svolta in aree selezionate dell'offshore pugliese tra Brindisi e S. Maria di Leuca si inquadra in un più ampio contesto di un programma di ricerca multidisciplinare dedicato allo studio delle aree di piattaforma continentale dell'Italia meridionale ed è stato sviluppato nell'ottica di un confronto tra il record geologico e morfologico del Pleistocene-Olocene e l'ambiente biologico e fisico attuale.

Altres ajuts: Unidad de excelencia María de Maeztu CEX2019-000940-M; Universidade de Vigo's programme to attract excellent research talent (RR04092017) The eastern Mediterranean Sea lies under the influence of high- and low-latitude climatic systems. The northern part of the basin is affected by Atlantic depressions and continental and polar air masses that promote intermediate and deep-water formation. The southern part is influenced by subtropical conditions and monsoon activity. Monsoon intensification results in enhanced freshwater discharge from the Nile River and other (now dry) systems along the North African margin. This freshwater influx into the Mediterranean Sea reduces surface water buoyancy loss. Disentangling the influences of these diverse climatic forcings is hindered by inherent proxy data limitations and by interactions between the climatic forcings. Here we use a wealth of published and new paleoclimate records across Termination II to understand the impacts of the higher latitude and subtropical/monsoon climate influences on coccolithophore ecology and holococcolith preservation in Aegean Sea sediment core LC21. We then use these findingsto interpret coccolith assemblage variations at Ocean Drilling Program Site 967 (located nearby LC21, at the Eratosthenes Seamount) during multiple glacial-interglacial cycles across the Middle Pleistocene (marine isotopic stages 14-9). The LC21 analysis suggests that holococcolith preservation was enhanced during Heinrich Stadial 11 (∼133 ka) and cold spell C26 (∼119 ka). These two events have been previously linked to cold conditions in the North Atlantic and Atlantic Meridional Overturning Circulation weakening. We propose that associated atmospheric perturbations over the Mediterranean Sea promoted deep-water formation, and thus holococcolith preservation. Similarly, in the Middle Pleistocene (MIS 14-9) of Site 967, we observe temporal coincidence between ten episodes of enhanced holococcolith preservation and episodes of Atlantic Meridional Overturning Circulation slowdown. In Site 967, we also identified repeated fluctuations in placoliths and in Florisphaera profunda, which indicate nutricline depth variations. The development of a deep chlorophyll maximum is associated with the North Africa and wet phases, as recently observed using elemental proxy records at Site 967, during the deposition of sapropel layers. A further deep chlorophyll maximum development is identified during MISs 12 and 10, as a result of pycnocline and nutricline shoaling within the lower part of the photic zone due to glacial sea-level lowering and water mass transport reduction at both the Gibraltar and Sicily Straits. Finally, enhanced holococcolith preservation during cold/dry events is clearly correlated to weakened monsoon activity in both Africa and Asia.