Status and results from cabled hydrophones arrays deployed in deep sea off East Sicily (EMSO-ERIC node)

Abstract

Since 2005 a cabled deep-sea infrastructure is operative at 2100 m water depth, 25 km off the port of Catania (Sicily). The infrastructure, under continuous improvement, is the first operative cabled node of the EMSO-ERIC, hosting several multidisciplinary observatories built in collaboration by INFN, INGV, CNR, CIBRA, and other scientific partners. Hydrophones antennas, sensitive in the range of frequencies between 1 Hz and 90 kHz, have been installed on seafloor observatories. Acoustic data are continuously digitized in situ at very high resolution, time-stamped with absolute GPS time and sent to shore in real time, through optical fiber link. Together with biological sounds, noise pollution study and monitoring were the main goals of the research. Results of multi-year monitoring of anthropogenic noise are discussed. Focus of the analysis is the noise level in the octave bands centered at 63 Hz and 125 Hz, in compliance with the EU Marine Strategy Framework Directive. The contribution of ship noise was modeled, based on their data recorded via proprietary AIS antennas, and compared to data. Noise at higher frequencies was also investigated. Detection of air-guns emissions and recorded noise levels is reported. Status and coming activities at the infrastructure is also presented.