Oceanographic signals at the Benthic Boundary Layer in the Mediterranean Sea

The Benthic Boundary Layer (BBL) is considered a quite homogeneous environment where a wide variety of processes (chemical, physical, geological and biological) occur often producing front structures or inducing turbulence phenomena. The typical stratification of these zones can be interrupted by episodic events which effects can diffuse to the ocean interior exploiting by local current and mixing processes. According to hydrodynamic definition, the BBL thickness may vary from few millimetres up to 100 metres depending on the friction intensity with the sea bed and the stability of water column above it. Generally in deep-sea condition, the BBL thickness is defined by the ratio between the friction velocity and the Coriolis parameter according to the Ekman scale. In the latest years several experiments have been carried out in the deep water of Mediterranean Sea, focusing on the survey and study of benthic processes following a multidisciplinary approach. Benthic observatories, such as SN-1 and GEOSTAR, allow to record long time-series of geochemical, seismological, geomagnetic, geodetic and oceanographic data and allow to understand the dynamics and evolution of the processes though comparison and interpolation of different types of signals. From a oceanographic point of view, the technology of these benthic observatories brings the possibility to observe and measure directly the hydrological properties at the seafloor collecting data for long-time series and with high sampling rate. The observatories deployed in Mediterranean Sea, have provided good information about variations and oscillations of hydrological parameters in deep water where the monitoring is almost lacking. In some cases it has been possible to link these deep-sea datasets with upper data collected by ship-handled system during the same period or during different cruises. This allows to have a more complete idea of the linkage between surface, intermediate and bottom sea. Hence the multidisciplinary approach represents a very important aspect for this kind of study, because it allows not only a cross check of functionality among all the instruments but also an important tool to recognise and better understand possible nonphysical- oceanographic phenomena

Environmental Noise and Nonlinear Relaxation in Biological Systems

We analyse the effects of environmental noise in three different biological systems: (i) mating behaviour of individuals of \emph{Nezara viridula} (L.) (Heteroptera Pentatomidae); (ii) polymer translocation in crowded solution; (iii) an ecosystem described by a Verhulst model with a multiplicative L\'{e}vy noise.Comment: 32 pages; In "Ecological Modeling" by Ed. Wen-Jun Zhang. ISBN: 978-1-61324-567-5. - Nova Science Publishers, New York, 201

Tsunami Warning prototype in the frame of the EC NEAREST project.

Nell' ambito del progetto NEAREST finanziato dalla EC sono stati sviluppati alcuni elementi di un sistema di allerta per tsunami, fra i quali un prototipo di detector di onde anomale istallato a bordo dell' osservatorio abissale GEOSTAR: l' osservatorio con il detector di onde anomale ha operato per un anno nel Golfo di Cadice, a 3200m di profonditàPublishedSassari1.8. Osservazioni di geofisica ambientaleope

Monitoring of a methane-seeping pockmark by cabled benthic observatory (Patras Gulf, Greece)

A new seafloor observatory, the gas monitoring module (GMM), has been developed for continuous and long-term measurements of methane and hydrogen sulphide concentrations in seawater, integrated with temperature (T), pressure (P) and conductivity data at the seafloor. GMM was deployed in April 2004 within an active gas-bearing pockmark in the Gulf of Patras (Greece), at a water depth of 42 m. Through a submarine cable linked to an onshore station, it was possible to remotely check, via direct phone connection, GMM functioning and to receive data in nearreal time. Recordings were carried out in two consecutive campaigns over the periods April–July 2004, and September 2004–January 2005, amounting to a combined dataset of ca. 6.5 months. This represents the first long-term monitoring ever done on gas leakage from pockmarks by means of CH4+H2S+T+P sensors. The results show frequent T and P drops associated with gas peaks, more than 60 events in 6.5 months, likely due to intermittent, pulsation-like seepage. Decreases in temperature in the order of 0.1–1°C (up to 1.7°C) below an ambient T of ca. 17°C (annual average) were associated with short-lived pulses (10–60 min) of increased CH4+H2S concentrations. This seepage “pulsation” can either be an active process driven by pressure build-up in the pockmark sediments, or a passive fluid release due to hydrostatic pressure drops induced by bottom currents cascading into the pockmark depression. Redundancy and comparison of data from different sensors were fundamental to interpret subtle proxy signals of temperature and pressure which would not be understood using only one sensor.Published297-302JCR Journalreserve

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by 40K decays but it can detect other natural (e.g., 238U,232Th) and anthropogenic radio-nuclides (e.g., 137Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea.In press4.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalope

GEMS: Underwater spectrometer for long-term radioactivity measurements

GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by 40K decays but it can detect other natural (e.g., 238U,232Th) and anthropogenic radio-nuclides (e.g., 137Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea

Observing Volcanoes from the Seafloor in the Central Mediterranean Area

The three volcanoes that are the object of this paper show different types of activity that are representative of the large variety of volcanism present in the Central Mediterranean area. Etna and Stromboli are sub-aerial volcanoes, with significant part of their structure under the sea, while the Marsili Seamount is submerged, and its activity is still open to debate. The study of these volcanoes can benefit from multi-parametric observations from the seafloor. Each volcano was studied with a different kind of observation system. Stromboli seismic recordings are acquired by means of a single Ocean Bottom Seismometer (OBS). From these data, it was possible to identify two different magma chambers at different depths. At Marsili Seamount, gravimetric and seismic signals are recorded by a battery-powered multi-disciplinary observatory (GEOSTAR). Gravimetric variations and seismic Short Duration Events (SDE) confirm the presence of hydrothermal activity. At the Etna observation site, seismic signals, water pressure, magnetic field and acoustic echo intensity are acquired in real-time thanks to a cabled multi-disciplinary observatory (NEMO-SN1 ). This observatory is one of the operative nodes of the European Multidisciplinary Seafloor and water-column Observatory (EMSO; www.emso-eu.org) research infrastructure. Through a multidisciplinary approach, we speculate about deep Etna sources and follow some significant events, such as volcanic ash diffusion in the seawater

Observing Volcanoes from the Seafloor in the Central Mediterranean Area

The three volcanoes that are the object of this paper show different types of activity that are representative of the large variety of volcanism present in the Central Mediterranean area. Etna and Stromboli are sub-aerial volcanoes, with significant part of their structure under the sea, while the Marsili Seamount is submerged, and its activity is still open to debate. The study of these volcanoes can benefit from multi-parametric observations from the seafloor. Each volcano was studied with a different kind of observation system. Stromboli seismic recordings are acquired by means of a single Ocean Bottom Seismometer (OBS). From these data, it was possible to identify two different magma chambers at different depths. At Marsili Seamount, gravimetric and seismic signals are recorded by a battery-powered multi-disciplinary observatory (GEOSTAR). Gravimetric variations and seismic Short Duration Events (SDE) confirm the presence of hydrothermal activity. At the Etna observation site, seismic signals, water pressure, magnetic field and acoustic echo intensity are acquired in real-time thanks to a cabled multi-disciplinary observatory (NEMO-SN1 ). This observatory is one of the operative nodes of the European Multidisciplinary Seafloor and water-column Observatory (EMSO; www.emso-eu.org) research infrastructure. Through a multidisciplinary approach, we speculate about deep Etna sources and follow some significant events, such as volcanic ash diffusion in the seawater.Published2983A. Ambiente MarinoJCR Journalrestricte

Multiparametric seafloor exploration: the Marsili Basin and Volcanic Seamount case (Tyrrhenian Sea, Italy)

Exploration of ocean seafloor is of paramount importance for a better understanding of the geodynamic evolution of our Planet. The pilot experiment of ORION-GEOSTAR 3 EC project was the first long-term continuous geophysical and oceanographic experiment of an important seafloor area of Southern Tyrrhenian Sea, the Marsili abyssal plain. The latter hosts the Marsili Seamount which is Europe’s one of the largest underwater volcano of Plio-Pleistocenic age. In spite of its dimensions, it is rather unknown about the present characteristics and activity. For this reason, we deployed a deep-sea observatory network, composed by two bottom observatories, on the seafloor at the base of the seamount at 3320 m b.s.l., in the period December 2003-May 2005. Some of the instruments on board the observatory were: broad-band seismometers, hydrophones, gravity meter, two magnetometers (scalar and vectorial), 3D single-point current meter, ADCP, CTD, automatic pH analyser and off-line water sampler for laboratory analyses. The first successful scientific objective was to obtain long-term continuous recordings under a unique time reference. The data analysis shows that they are generally of good quality and really continuous (only a few gaps). As a first step we performed a classification of seismic waveforms, a first inversion of magnetic variational data, and a first analysis of gravity meter, chemical and oceanographic data. Analysis of individual time series has shown interesting results, i.e. depth of the magnetic Moho under the Marsili, attenuation of recorded seismic body waves and clues of hydrothermal circulation. We show examples of the preliminary data analysis together with first results and comparisons among data coming from different sensors.PublishedCambridge, UK, February 24-26, 20091.8. Osservazioni di geofisica ambientale3.8. Geofisica per l'ambienteope

Multiparametric seafloor exploration: the Marsili Basin and Volcanic Seamount case (Tyrrhenian Sea, Italy)

Exploration of ocean seafloor is of paramount importance for a better understanding of the geodynamic evolution of our Planet. The pilot experiment of ORION-GEOSTAR 3 EC project was the first long-term continuous geophysical and oceanographic experiment of an important seafloor area of Southern Tyrrhenian Sea, the Marsili abyssal plain. The latter hosts the Marsili Seamount which is Europe’s one of the largest underwater volcano of Plio-Pleistocenic age. In spite of its dimensions, it is rather unknown about the present characteristics and activity. For this reason, we deployed a deep-sea observatory network, composed by two bottom observatories, on the seafloor at the base of the seamount at 3320 m b.s.l., in the period December 2003-May 2005. Some of the instruments on board the observatory were: broad-band seismometers, hydrophones, gravity meter, two magnetometers (scalar and vectorial), 3D single-point current meter, ADCP, CTD, automatic pH analyser and off-line water sampler for laboratory analyses. The first successful scientific objective was to obtain long-term continuous recordings under a unique time reference. The data analysis shows that they are generally of good quality and really continuous (only a few gaps). As a first step we performed a classification of seismic waveforms, a first inversion of magnetic variational data, and a first analysis of gravity meter, chemical and oceanographic data. Analysis of individual time series has shown interesting results, i.e. depth of the magnetic Moho under the Marsili, attenuation of recorded seismic body waves and clues of hydrothermal circulation. We show examples of the preliminary data analysis together with first results and comparisons among data coming from different sensors