Snap chat: listening in on the peculiar acoustic patterns of snapping shrimp, the noisiest animals on the reef
Ashlee Lillis – ashlee@whoi.edu
T. Aran Mooney – amooney@whoi.edu
Marine Research Facility
Woods Hole Oceanographic Institution
266 Woods Hole Road
Woods Hole, MA 02543
Popular version of paper 2pABa1
Presented Tuesday afternoon, November 29, 2016
172nd ASA Meeting, Honolulu
Characteristic soundscape recorded on a coral reef in St. John, US Virgin Islands. The conspicuous crackle is produced by many tiny snapping shrimp.
Put your head underwater in almost any tropical or sub-tropical coastal area and you will hear a continuous, static-like noise filling the water. The source of this ubiquitous sizzling sound found in shallow-water marine environments around the world was long considered a mystery of the sea. It wasn’t until WWII investigations of this underwater sound, considered troublesome, that hidden colonies of a type of small shrimp were discovered as the cause of the pervasive crackling sounds (Johnson et al., 1947).
Individual snapping shrimp (Figure 1), sometimes referred to as pistol shrimp, measure smaller than a few centimeters, but produce one of the loudest of all sounds in nature using a specialized snapping claw. The high intensity sound is actually the result of a bubble popping when the claw is closed at incredibly high speed, creating not only the characteristic “snap” sound but also a flash of light and extremely high temperature, all in a fraction of a millisecond (Versluis et al., 2000). Because these shrimp form large, dense aggregations, living unseen within reefs and rocky habitats, the combination of individual snaps creates the consistent crackling sound familiar to mariners. Snapping is used by shrimp for defense and territorial interactions, but likely serves other unknown functions based on our recent studies.
[Insert Figure 1. Images of the species of snapping shrimp, Alpheus heterochaelis, we are using to test hypotheses in the lab. This isthe dominant species of snapping shrimp found coastally in the Southeast United States, but there are hundreds of different species worldwide, easily identified by their relatively large snapping claw. ]
Since snapping shrimp produce the dominant sound in many marine regions, changes in their activity or population substantially alters ambient sound levels at a given location or time. This means that the behavior of snapping shrimp exerts an outsized influence on the sensory environment for a variety of marine animals, and has implications for the use of underwater sound by humans (e.g., harbor defense, submarine detection). Despite this fundamental contribution to the acoustic environment of temperate and coral reefs, relatively little is known about snapping shrimp sound patterns, and the underlying behaviors or environmental influences. So essentially, we ask the question: what is all the snapping about?
[Insert Figure 2. Photo showing an underwater acoustic recorder deployed in a coral reef setting. Recorders can be left to record sound samples at scheduled times (e.g. every 10 minutes) so that we can examine the long-term temporal trends in snapping shrimp acoustic activity on the reef.]
Recent advances in underwater recording technology and interest in passive acoustic monitoring have aided our efforts to sample marine soundscapes more thoroughly (Figure 2), and we are discovering complex dynamics in snapping shrimp sound production. We collected long-term underwater recordings in several Caribbean coral reef systems and analyzed the snapping shrimp snap rates. Our soundscape data show that snap rates generally exhibit daily rhythms (Figure 3), but that these rhythms can vary over short spatial scales (e.g., opposite patterns between nearby reefs) and shift substantially over time (e.g., daytime versus nighttime snapping during different seasons). These acoustic patterns relate to environmental variables such as temperature, light, and dissolved oxygen, as well as individual shrimp behaviors themselves.
[Insert Figure 3. Time-series of snap rates detected on two nearby USVI coral reefs for a week-long recording period. Snapping shrimp were previously thought to consistently snap more during the night, but we found in this study location that shrimp were more active during the day, with strong dawn and dusk peaks at one of the sites. This pattern conflicts with what little is known about snapping behaviors and is motivating further studies of why they snap.]
The relationships between environment, behaviors, and sound production by snapping shrimp are really only beginning to be explored. By listening in on coral reefs, our work is uncovering intriguing patterns that suggest a far more complex picture of the role of snapping shrimp in these ecosystems, as well as the role of snapping for the shrimp themselves. Learning more about the diverse habits and lifestyles of snapping shrimp species is critical to better predicting and understanding variation in this dominant sound source, and has far-reaching implications for marine ecosystems and human applications of underwater sound.
References
Johnson, M. W., F. Alton Everest, and Young, R. W. (1947). “The role of snapping shrimp (Crangon and Synalpheus) in the production of underwater noise in the sea,” Biol. Bull. 93, 122–138.
Versluis, M., Schmitz, B., von der Heydt, A., and Lohse, D. (2000). “How snapping shrimp snap: through cavitating bubbles,” Science, 289, 2114–2117. doi:10.1126/science.289.5487.2114
How virtual reality technologies can enable better soundscape design.
W.M. To – wmto@ipm.edu.mo
Macao Polytechnic Institute, Macao SAR, China.
A. Chung – ac@smartcitymakter.com
Smart City Maker, Denmark.
B. Schulte-Fortkamp – b.schulte-fortkamp@tu-berlin.de
Technische Universität Berlin, Berlin, Germany.
Popular version of paper 2aNS, “How virtual reality technologies can enable better soundscape design”
Presented Tuesday morning, November 29, 2016
172nd ASA Meeting, Honolulu
The quality of life including good sound quality has been sought by community members as part of the smart city initiative. While many governments have placed special attention to waste management, air and water pollution, acoustic environment in cities has been directed toward the control of noise, in particular, transportation noise. Governments that care about the tranquility in cities rely primarily on setting the so-called acceptable noise levels i.e. just quantities for compliance and improvement [1]. Sound quality is most often ignored. Recently, the International Organization for Standardization (ISO) released the standard on soundscape [2]. However, sound quality is a subjective matter and depends heavily on the perception of humans in different contexts [3]. For example, China’s public parks are well known to be rather noisy in the morning due to the activities of boisterous amateur musicians and dancers – many of them are retirees and housewives – or “Da Ma” [4]. These activities would cause numerous complaints if they would happen in other parts of the world, but in China it is part of everyday life.
According to the ISO soundscape guideline, people can use sound walks, questionnaire surveys, and even lab tests to determine sound quality during a soundscape design process [3]. With the advance of virtual reality technologies, we believe that the current technology enables us to create an application that immerses designers and stakeholders in the community to perceive and compare changes in sound quality and to provide feedback on different soundscape designs. An app has been developed specifically for this purpose. Figure 1 shows a simulated environment in which a student or visitor arrives the school’s campus, walks through the lawn, passes a multifunctional court, and get into an open area with table tennis tables. She or he can experience different ambient sounds and can click an object to increase or decrease the volume of sound from that object. After hearing sounds at different locations from different sources, the person can evaluate the level of acoustic comfort at each location and express their feelings toward overall soundscape. She or he can rate the sonic environment based on its degree of perceived loudness and its level of pleasantness using a 5-point scale from 1 = ‘heard nothing/not at all pleasant’ to 5 = ‘very loud/pleasant’. Besides, she or he shall describe the acoustic environment and soundscape using free words because of the multi-dimensional nature of sonic environment.
Figure 1. A simulated soundwalk in a school campus.
To, W. M., Mak, C. M., and Chung, W. L.. Are the noise levels acceptable in a built environment like Hong Kong? Noise and Health, 2015. 17(79): 429-439.
ISO. ISO 12913-1:2014 Acoustics – Soundscape – Part 1: Definition and Conceptual Framework, Geneva: International Organization for Standardization, 2014.
Kang, J. and Schulte-Fortkamp, B. (Eds.). Soundscape and the Built Environment, CRC Press, 2016.
Brigitte Schulte-Fortkamp – b.schulte-fortkamp@tu-berlin.de
Technical University Berlin
Institute of Fluid Mechanics and Engineering Acoustics
-Psychoacoustics and Noise effects –
Einsteinufer 25
10587 Berlin -Germany
Popular version of paper 2aNSa1, “Soundscape as a resource to balance the quality of an acoustic environment”
Tuesday morning, May 19, 2015, 8:35 AM, Commonwealth 1
169th ASA Meeting, Pittsburgh Pennsylvania
Preface
Soundscape studies investigate and find increasingly better ways to measure and hone the acoustic environment. Soundscape offers the opportunity for multidisciplinary working, bringing together science, medicine, social studies and the arts – combined, crucially, with analysis, advice and feedback from the ‘users of the space’ as the primary ‘experts’ of any environment – to find creative and responsive solutions for protection of living places and to enhance the quality of life.
The Soundscape concept was introduced as a scope to rethink the evaluation of “noise” and its effects. The challenge was to consider the limits of acoustic measurements and to account for its cultural dimension.
The recent international standard ISO 12913-1 Acoustics — Soundscape —Part 1: Definition and conceptual framework Acoustique – Paysage sonore -Partie 1: Définition et cadre conceptual clarifies soundscape as an “acoustic environment as perceived or experienced and/or understood by a person or people, in context”
Figure 1 — Elements in the perceptual construct of soundscape
Soundscape suggests exploring noise in its complexity and its ambivalence and its approach towards sound to consider the conditions and purposes of its production, perception, and evaluation, to understand evaluation of noise/ sound as a holistic approach.
To discuss the contribution of Soundscape research into the area of Community noise research means to focus on the meaning of sounds and its implicit assessments to contribute to the understanding that the evaluation through perceptual effects is a key issue.
Using the resources- an example-
Soundscape Approach Public Space Perception and Enhancement Drawing on Experience in Berlin
Figure 2- Soundscape Nauener Platz
The concept of development of the open pace relies on the understanding that people living in the chosen are the “real” experts concerning the evaluation of this place according to their expectations and experiences in the respective area. The intention of scientific research here is to learn about the meaning of the noise with respect to people’s living situation and to implement the adequate procedure to open the “black box” of people’s mind.
Therefore, the aim was to get residents involved through workshops to get access to the different social groups.
Figure 3- Partipation and Collaboration
Figure 4- The concept of evaluation
Interdisciplinarity is considered as a must in the soundscape approach. In this case it was concerned with the collaboration of architects, acoustics engineers, environmental health specialists, psychologists, social scientists, and urban developers. The tasks are related to the local individual needs and are open to noise sensitive and other vulnerable groups. It is also concerned with cultural aspects and the relevance of natural soundscapes – sometimes referred to as quiet areas – which is obviously related to the highest level of needs.
Figure 5 – Soundscape – an interactive approach using the resources
Improving local soundscape quality?
Obviously, these new approaches and methods make it possible to learn about the process of perception and evaluation sufficiently as they take into account the context, ambiance, the usual interaction between noise and listener and the multidimensionality of noise perception.
By contrast, conventional methods often reduce the complexity of reality on controllable variables, which supposedly represent the scrutinized object. Furthermore, traditional tests neglect frequently the context-dependency of human perception; they only provide artificial realities and diminish the complexity of perception on merely predetermined values, which do not completely correspond with perceptual authenticity. However, perception and evaluations entirely depend on the respective influences of the acoustic and non-acoustic modifiers.
Following the comments and group discussion and also the results from the narrative interviews it could be defined why people prefer some places over the public place and why not. It also became clear how people experience the noise in the distance from the road and also with respect to social life and social control. One of the most important findings here is how people react to low frequency noise at the public place and how experiences and expectations work together. It becomes obvious that the most wanted sound in this area is based on wishes to escape the road traffic noise through natural sounds.
Figure 6- Selected sounds for audio islands
Reshaping the place based on people’s expertise
Relying on the combined evaluation procedures the place was reshaped installing a gabion wall along one of the main roads and further more audio islands like have been built that integrated the sounds people would like to enjoy when using the place. While the gabion wall protects against noise around the playground, the new installed audio islands provide nature sounds as selected by the people involved in the Soundscape approach.
Figure 7 –Installation of the sounds
Conclusions
Figure 8 – The new place
The process of tuning of urban areas with respect to the expertise of people’s mind and quality of life is related to the strategy of triangulation and provides the theoretical frame with regard to the solution of e.g. the change in an area. In other words: Approaching the field in this holistic manner is generally needed.
An effective and sustainable reduction of the number of highly annoyed people caused by noise is only possible with further scientific endeavors in the area of methods development and research of noise effects. Noise maps providing further information can help to obtain a deeper understanding of noise reactions and can help to reliably identify perception-related hot spots. Psychoacoustic maps are particularly interesting in areas where the noise levels are marginal below the noise level limits and offer an additional interpretation help with respect to the identification of required noise abatement measures.
But, the expertise of people involved will provide meaningful information. Soundwalks as an eligibly instrument for exploring urban areas by minds of the “local experts” as measuring device open a field of data for triangulation. These techniques in combination allow giving meaning to the numbers and values of recordings and their analysis to understand the significance of sound and noise as well as the perception of Soundscapes by its resources.
tags: soundscape, acoustics, people, health
REFERENCES
J. Kang, B. Schulte-Fortkamp (editors) Soundscape and the Built Environment CRC Press | Taylor & Francis Group, in print
B. Schulte-Fortkamp, J. Kang (editors) Special Issue on Soundscape, JASA 2012
R. M. Schafer, “The Soundscape. Our sonic environment and the tuning of the world.” Rochester, Vermont: Destiny Books, (1977).
B. Hollstein, “Qualitative approaches to social reality: the search for meaning” in: John Scott & Peter J. Carrington (Eds.): Sage handbook of social network analysis. London/Newe Dehli: Sage. (2012)
R. M. Schafer, “The Book of Noise” (Price Milburn Co., Lee, Wellington, NZ, (1973).
B. Truax, (ed.) „Handbook for Acoustic Ecology” (A.R.C. Publication, Vancouver, (1978).
K. Hiramatsu, “Soundscape: The Concept and Its Significance in Acoustics,” Proc. ICA, Kyoto, 2004.
A. Fiebig, B. Schulte-Fortkamp, K. Genuit, „New options for the determination of environmental noise quality”, 35th International Congress and Exposition on Noise Control Engineering INTER-NOISE 2006, 04.-06.December 2006, Honolulu, HI.
P. Lercher, B. Schulte-Fortkamp, “Soundscape and community noise annoyance in the context of environmental impact assessments,” Proc. INTER-NOISE 2003, 2815-2824, (2003).
B. Schulte-Fortkamp, D. Dubois: (editors) Acta Acustica united with Acustica, Special Issue, Recent advances in Soundscape research, Vol 92 (6), (2006).
R. Klaboe, et. al. „Änderungen in der Klang- und Stadtlandschaft nach Änderung von Straßenverkehrsstraßen im Stadtteil Oslo-Ost“, Fortschritte der Akustik, Oldenburg, (2000).
