Ocean noise: Making sense of sounds

The growing scientific and societal concern about the effects of underwater sound on marine ecosystems has recently been recognized through the introduction of several international initiatives aimed at measuring the environmental impact of ocean noise on large spatial and temporal scales. From a regulatory perspective, the European Marine Strategy Framework Directive includes noise as one of 11 descriptors to determine Good Environmental Status of the oceans. The Directive specifically requires European Union (EU) Member States to provide a measure of annually averaged noise. The international program LIDO (Listening to the Deep-Ocean Environment) has developed a software package that measures sound levels and monitors acoustic sources in real-time on a global scale; this software is now operating to provide industry with an environmentally responsible approach. The system is currently operating worldwide from several wired and radio- or satellite-linked platforms. It includes the automatic identification of acoustic events (physical processes, biological sounds and artificial noise) and the measurement of noise contributions from anthropogenic sources. Continuous monitoring of background noise will indeed help us to understand whether long-term exposures to noise, in areas with intense shipping or seismic campaigns, for instance, might alter animal natural behaviour and may be used in the future to assess the effects of ocean noise on marine life