Report of the Workshop on International Harmonisation of Approaches to Define Underwater Noise Exposure Criteria (Budapest, Hungary 17th August 2013)

The potential negative effects of high levels of underwater noise on marine life have been identified and acknowledged, and this issue has been incorporated into various international agreements over the past decade. Several countries have already issued regulations to limit the incidence and level of anthropogenic noise in the oceans. The development of regulations on noise exposure in marine environments has to date focused on two groups, marine mammals and, to a lesser extent, fishes. Nevertheless, our understanding of the complexity of acoustic and behavioural effects is improving, and it might be possible to develop existing noise-exposure criteria with scientific knowledge evolving. More importantly, new regulations, or at least the approaches taken toward regulations, could be internationally harmonised to provide better protection for marine fauna

25 Years of Self-organized Criticality: Concepts and Controversies

Introduced by the late Per Bak and his colleagues, self-organized criticality (SOC) has been one of the most stimulating concepts to come out of statistical mechanics and condensed matter theory in the last few decades, and has played a significant role in the development of complexity science. SOC, and more generally fractals and power laws, have attracted much comment, ranging from the very positive to the polemical. The other papers (Aschwanden et al. in Space Sci. Rev., 2014, this issue; McAteer et al. in Space Sci. Rev., 2015, this issue; Sharma et al. in Space Sci. Rev. 2015, in preparation) in this special issue showcase the considerable body of observations in solar, magnetospheric and fusion plasma inspired by the SOC idea, and expose the fertile role the new paradigm has played in approaches to modeling and understanding multiscale plasma instabilities. This very broad impact, and the necessary process of adapting a scientific hypothesis to the conditions of a given physical system, has meant that SOC as studied in these fields has sometimes differed significantly from the definition originally given by its creators. In Bak’s own field of theoretical physics there are significant observational and theoretical open questions, even 25 years on (Pruessner 2012). One aim of the present review is to address the dichotomy between the great reception SOC has received in some areas, and its shortcomings, as they became manifest in the controversies it triggered. Our article tries to clear up what we think are misunderstandings of SOC in fields more remote from its origins in statistical mechanics, condensed matter and dynamical systems by revisiting Bak, Tang and Wiesenfeld’s original papers

Some Unique Features of the Ear and the Lateral Line of a Catfish and Their Potential Bearing for Sound Pressure Detection The Evolutionary Biology of Hearing

Bleckmann H, Fritzsch B, Niemann U, Müller HM. Some Unique Features of the Ear and the Lateral Line of a Catfish and Their Potential Bearing for Sound Pressure Detection The Evolutionary Biology of Hearing. In: Popper AN, Fay RR, Webster DB, eds. The Evolutionary Biology of Hearing. New York: Springer; 1991: 455

Soundscape: The Holistic Understanding of Acoustic Environments

The expanded recognition of soundscape studies has resulted in a research domain composed of various disciplinary perspectives and, at times, contradictory interpretations of what is meant by “soundscape.” At its core, soundscape is a construct of human perception that factors in the entirety of an acoustic environment and the individual’s responses to it. This stands in contrast to the acoustic environment, which is simply the composition of acoustic stimuli in an environment. The baseline of human perception in soundscape was recognized by the International Organization for Standardization in ISO 12913-1 (ISO 2014), which emphasizes the interrelationships between person, activity, and physical place in both space and time. The breadth of one’s responses beyond auditory sensation can be much more complex than reactions to noise. The meaning an individual ascribes to sounds, individual’s attitude and expectations toward the acoustic environment, socioeconomic and cultural background, and life experiences all play a role. The complexity of interrelationships between context and listener can only be understood through a multilateral, holistic approach in the field of soundscape study. This chapter traces the broad trajectory of soundscape studies to contextualize a holistic approach and concludes by highlighting various holistic research projects that sought to enhance the quality of acoustic environments and living situations

Intense ultrasonic clicks from echolocating toothed whales do not elicit anti-predator responses or debilitate the squid Loligo pealeii

Toothed whales use intense ultrasonic clicks to echolocate prey and it has been hypothesized that they also acoustically debilitate their prey with these intense sound pulses to facilitate capture. Cephalopods are an important food source for toothed whales, and there has probably been an evolutionary selection pressure on cephalopods to develop a mechanism for detecting and evading sound-emitting toothed whale predators. Ultrasonic detection has evolved in some insects to avoid echolocating bats, and it can be hypothesized that cephalopods might have evolved similar ultrasound detection as an anti-predation measure. We test this hypothesis in the squid Loligo pealeii in a playback experiment using intense echolocation clicks from two squid-eating toothed whale species. Twelve squid were exposed to clicks at two repetition rates (16 and 125 clicks per second) with received sound pressure levels of 199–226 dB re 1 μPa (pp) mimicking the sound exposure from an echolocating toothed whale as it approaches and captures prey. We demonstrate that intense ultrasonic clicks do not elicit any detectable anti-predator behaviour in L. pealeii and that clicks with received levels up to 226 dB re 1 μPa (pp) do not acoustically debilitate this cephalopod species

Adaptive Plasticity in Perceiving Speech Sounds

Listeners can rely on perceptual learning and recalibration in order to make reliable interpretations during speech perception. Lexical and audiovisual (or speech-read) information can disambiguate the incoming auditory signal when it is unclear, due to speaker-related characteristics, such as an unfamiliar accent, or due to environmental factors, such as noise. With experience, listeners can learn to adjust boundaries between phoneme categories as a means of adaptation to such inconsistencies. Recalibration experiments tend to use a targeted approach by embedding ambiguous phonemes into speech or speechlike items, and with continuous exposure, a learning effect can be induced in listeners, wherein disambiguating contextual information shifts the perceived identity of the same ambiguous sound. The following chapter will review current and past literature regarding lexical and audiovisual influences on phoneme boundary recalibration, as well as theories and neuroimaging data that potentially reveal what facilitates this perceptual plasticity.keywordsrecalibrationperceptual learningspeech perceptionphonetic processinglexical processingaudiovisual speechspeech-reading