Underwater noise in the Slovenian Sea

Abstract

Continuous underwater noise has been monitored in the Slovenian sea near the lighthouse foundation at Debeli Rtič since February 2015, according to the EU Marine Strategy Framework Directive (MSFD). Anthropogenic noise sources (e.g. seawater densities, dredging activities and cleaning of the seafloor) and meteorological noise sources (e.g. wind speed and precipitation) were analysed in relation to the measured underwater noise levels using several graphical and statistical methods. The results of this study showed that average equivalent continuous underwater noise levels were, by 11 dB (L eq,63 Hz) and 5 dB (L eq,125 Hz), higher in the intervals when dredging activities took place than in the intervals when these activities were absent. Variation in underwater noise levels was partly related to the variation of the ship densities, which could be explained by the relatively small acoustic propagation in the shallow seawater. Precipitation level did not indicate any significant association with the variations in continuous underwater noise levels, though some larger deviations in the wind speed were found to be associated with the larger fluctuations in continuous underwater noise levels.

A decade of underwater noise research in support of the European Marine Strategy Framework Directive

“…SOUNDSCAPE aims to establish joint monitoring, carry out a transnational noise assessment, and implement a planning tool for noise management. Various localised MSFD monitoring studies have also been carried out in the Mediterranean, notably in Italy (Codarin and Picciulin, 2015;Viola et al, 2017;Cafaro et al, 2018;Pieretti et al, 2020), Croatia (Rako et al, 2013;Picciulin et al, 2016;Vukadin, 2016), Montenegro ( Širović and Holcer, 2020), Greece (Prospathopoulos et al, 2017), and Slovenia (Popit, 2021).…”

First basin scale spatial-temporal characterization of underwater sound in the Mediterranean Sea

“…36 (Italy) (112 and 107 dB re 1 µPa at 63 Hz and 125 Hz TOB, respectively); in this case, data were collected at the extreme water depth of 2100 m. Recently, hourly 63 and 125 Hz TOB median values have been found mostly between 90 and 105 dB re 1 µPa during the winter period (November-March 2019): here37 , acoustic data were recorded at 1,000 m depth in the South-eastern Adriatic Sea, to the South of Split (MS8), approximately at 20 km west of Dubrovnik (Croatia).Monthly averaged SPLs ranged between 92 and 115 B re 1 µPa at 63 and 125 Hz TOBs in the yearly measurements in the port of Cartagena 38 (Spain) and median SPLs from 91 to 98 dB re 1 µPa at 63 Hz and 125 TOB s were recorded at the Gulf of Naples 39 along three months period (Italy), both areas being under intensive urban settlements and maritime tra c. These sound levels are comparable to the SOUNDSCAPE levels recorded in port areas as Split (MS8) and the Trieste Gulf (MS4). Continuous shorttime assessment run in the Trieste Gulf indicated also daily SPLs ranging between about 65 and 120 dB re 1 µPa at the 63 Hz and 125 Hz TOBs inside the Natural Marine Reserve of Miramare40 and average levels between 83 and 101 dB re 1 µPa at 63 Hz and 125 Hz TOBs in the Slovenian waters41 .…”