Research infrastructures for monitoring and study of marine environment

The Laboratori Nazionali del Sud, have realized and operate two submarine research infrastructures off Eastern Sicily: one, 2100 m deep and 25 km East of the Port of Catania; the second, 3500 m deep and about 90 km South-East of Capo Passero (SR). Both the infrastructures are connected to the shore lab at the Port of Catania by means an electro-optical cable that provides power supply to the abyssal observatories and allows the real time acquisition and transmission of the data. The shore laboratory of the Port is connected to the other LNS labs with an optical fibre system. This represents the wider network of real-time submarine observatories in the Mediterranean Sea.

Since the early 2000s, thanks to national, regional and European projects (NEMO, KM3NeT, EMSO-Medit and SMO), abyssal detectors equipped with acoustic, optical and environmental sensors have been installed for the study of particle astrophysics (KM3NeT project) and of the marine environment. The state-of-the-art technologies developed by INFN and its partners for the realization of the network and of the observatories have enabled the first long-term studies of the deep marine environment of the Ionian Sea with a variety of lines of research, and in particular on: Underwater acoustics, Marine Biology and Ecology and Oceanography.

Partners of the INFN in the multidisciplinary study of the deep marine environments are: INGV, CNR-IAMC, CIBRA-University of Pavia, ENEA, INOGS, Instituto de Ciencias del Mar - CSIC (Spain) University of Aberdeen (UK), University of Malta, University of Roma Tre, University of Messina, University of Catania, University of Palermo, University Cà Foscari of Venezia.

LNS are among the publishers and promoters of the White Paper for the reduction and mitigation of acoustic noise in the Italian seas. Click here to sign the petition.

Underwater acoustics

The projects NEMO - OvDE, NEMO - SN1 and SMO provided several information on the species of cetaceans present in the area and on submarine noise generated by various types of anthropogenic sources of noise. Thanks to the interdisciplinary collaboration between INFN and its partners, it was possible to carry out the first studies on the presence and population dynamics of sperm whales and on the eco-localization of dolphins. The observatories also allowed the first long-term monitoring of the presence of fin whales in the Gulf of Catania and the study of impulsive noise generated by "airguns". The latter sources are used for geoseismic prospections, for the study of the seabed and for search of submarine oil fields. Noise levels in the Gulf of Catania have also been continuously measured and correlated with ship traffic, which represents the main source of noise in the area.

Nowadays, the research and technological leadership of Laboratori Nazionali del Sud of the INFN in the field of underwater acoustics are widely recognized. Thanks to the results achieved, the LNS participates in the technical-scientific working group on the effects of the use of the airgun technique on the marine ecosystem, established by the Italian Ministry of the Environment and the Protection of the Territory and Sea (MATTM - Direzione Protezione Della Natura e Del Mare). The acoustic data acquired by INFN submarine observatories were also made available for the national monitoring required under the European Marine Strategy Framework Directive, with reference to Descriptor 11 (underwater noise).

Marine biology and ecology

The use of innovative technologies for the monitoring of the deep marine environment has allowed the development of new lines of research in the fields of marine biology and ecology. In particular, the optical sensors (photo multipliers) installed for the construction of the KM3NeT neutrino telescope have made possible the realization of studies on underwater bioluminescence with innovative methodologies in the Ionian Sea.

The NEMO Phase 2 prototype sensors have been used to detect and to study bioluminescence emission in deep sea environment and to describe the synchronization between the bioluminescence activity of abyss-pelagic organisms and hydrodynamic cycles. In the deep sea the perception of time depends on geophysical fluctuations, such as the internal tides and inertial currents, rather than by the diurnal and the nocturnal rhythms.

New applications linked to the construction of the KM3NeT telescope are currently under development and among the many possible studies, a particular interest now lays in the monitoring of plastics at sea (marine litter).

Oceanography

The installation of environmental monitoring sensors off the Eastern Sicily, since the preliminary stages of the KM3NeT project, has allowed the monitoring of environmental parameters of fundamental importance to conduct long-term studies on physical and biological oceanography. In particular, the presence of current-meters and sensors for the measure of temperature, pressure and conductivity allows an accurate monitoring of the movement of water masses and the study of deep currents and motions.

A first important achievement was already obtained in the early 2000s when the existence of abyssal vortexes has been evidenced offshore Eastern Sicily. These vortexes are wide water masses of about 10 kilometres in diameter, slowly moving at about three centimetres per second off east-Sicily.