Oceans of noise - Whale and Dolphin Conservation Society

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Box 2. The effects of temperature, salinity and pressure on sound speed Depth (m) Depth (m) Depth (m) -500 -1000 -1500 -2000 -2500 -3000 0 -1 4 9 -500 -1000 -1500 -2000 -2500 -3000 -500 -1000 -1500 -2000 -2500 -3000 T (°C) 0 27 37 47 S (PSU) 0 0 1000 2000 3000 P (Pa) Depth (m) Depth (m) Depth (m) -1000 -1500 -2000 -2500 -3000 -500 -1000 -1500 -2000 -2500 -3000 -500 -500 -1000 -1500 -2000 -2500 -3000 0 1400 1450 1500 17 C (ms -1 ) 0 1400 1450 1500 C (ms -1 ) SSM 0 1400 1450 1500 C (ms -1 ) SSM SSM Figure 2.6. The effects of temperature on sound speed (c). As temperature decreases with depth, speed (c) decreases. Above the Sound Speed Minimum (Vmin) changes in temperature with depth have the greatest influence on c. Below the SSM temperature is fairly constant, i.e. the water is isothermal. A change in temperature of 1°C (_T), results in a 3ms -1 change in c (_c). Figure 2.7. The effects of salinity on sound speed (c). A change in salinity (_S) of 1PSU results in a 1.3ms -1 change in c (_c). Figure 2.8. The effects of pressure on (c). As pressure increases with depth, (c) increases. Below the Sound Speed Minimum (Vmin) pressure has the greatest influence on c, as temperature and salinity remain fairly constant at depth. A change in pressure (_P) of 1Pa results in a 1.7ms -1 change in c (_c).
Intensity The intensity of a sound is defined as the acoustical power per unit area in the direction of propagation, i.e. Intensity is a measure of the mechanical (kinetic) energy and potential energy carried by a propagating wave per unit area. Note that the kinetic energy of a wave is the result of particle motion, and its potential energy results from the stresses set up in the elastic medium as the result of this motion. Intensity is proportional to the square of the acoustic pressure. I =∝ 2 p Where acoustic pressure (p) is defined as the sound force per unit area, and is usually measured in micropascals (µPa). Note that 1µPa is the pressure resulting from a force of one Newton exerted over an area of one square meter (Nm -2 ). The instantaneous pressure p(t) that a vibrating object exerts on an area is directly proportional to the vibrating object's velocity (v) and acoustic impedance (_c). p( t) = ρcv µ Pa Note that the product of density (_) and sound speed (c) is defined as the acoustic or characteristic impedance (_c) of that medium. Acoustic impedance (_c) is analogous to electrical resistance (impedance), and the differences (_ _c) in this value at a boundary between two media are an important determinant of how much energy is reflected by that boundary, see Snell’s Law. The acoustic impedance of water is 1.5x10 6 and of air is 4.15x10 2 kgm -2 s -1 . Thus the intensity of sound can be defined as: ⎛ ⎛ p ⎞ ⎞ ⎜ ⎜ ⎟ ⎟ ⎛ p ⎞ ⎜ ⎝ 2 = ⎜ ⎟ = ⎠ ⎟ = ⎝ ρc ⎠ ⎜ ρc ⎟ ⎜ ⎟ ⎝ ⎠ I e ρ cv 18 −2 Watts ⋅ m Where pe is the effective or RMS pressure, i.e. the peak pressure (amplitude) divided by the square root of two.
Page 1 and 2: Oceans of noise A WDCS Science repo
Page 3 and 4: Contents Author biographies 4 Prefa
Page 5 and 6: Author biographies Sarah Dolman Sar
Page 7 and 8: Preface Over the course of the last
Page 9 and 10: some thoughts on the mitigation and
Page 11 and 12: 1. Introduction Lindy Weilgart The
Page 13 and 14: 2. The physics of underwater sound
Page 15 and 16: Box 1. Characteristics of sound / l
Page 17: Box 2. The effects of temperature,
Page 21 and 22: For water, pref = 1µPa rms, _ = 1x
Page 23 and 24: 2.2. Types of sound source Sounds c
Page 25 and 26: Cylindrical spreading loss Cylindri
Page 27 and 28: Rain - - - - - - - - - 100-500 - Bi
Page 29 and 30: Energy source (Air gun array) 28 Se
Page 31 and 32: driving and pipe-laying (installati
Page 33 and 34: produced as the bubble collapses an
Page 35 and 36: and broadband noise sources decayed
Page 37 and 38: cetaceans to high levels of acousti
Page 39 and 40: Navigation (transponders) 38 7-60 1
Page 41 and 42: SONAR TYPE FREQUENCY RANGE AV. SOUR
Page 43 and 44: them from approaching fish farm cag
Page 45 and 46: 3.11. Research 3.11.1. Controlled E
Page 47 and 48: frequencies). These sound channels
Page 49 and 50: 4.3.6. Danger avoidance Many verteb
Page 51 and 52: Table 4.1. Summary of sound frequen
Page 53 and 54: Table 4.2. Summary of sound frequen
Page 55 and 56: 5. Noise as a problem for cetaceans
Page 57 and 58: Increased vulnerability to disease
Page 59 and 60: levels exceed the ear’s tolerance
Page 61 and 62: 5.6 A New Concern: Is noise causing
Page 63 and 64: stranding incident suggests that th
Page 65 and 66: The only cetaceans listed in Annex
Page 67 and 68: 6.4 The US Marine Mammal Protection
Page 69 and 70:
7. Solutions - mitigation and manag
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2. More targeted studies into each
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Noise pollution also needs to be co
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ange. Therefore prey must be closer
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identification of images collected.
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Pierson et al. (1998) indicated a m
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Baur, D.C., M.J. Bean, M.L. Gosline
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Cummings, W.C., Thompson, P.O. and
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Gedamke, J., Costa, D., Dunstan, A.
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Lagadere, J.P. 1982. Effects of noi
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National Research Council. 2000. Ma
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Sayigh, L.S., Tyack, P.L., Wells, R
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Todd, S., Lien, J. and Verhulst, A.
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December 1989, Pacific Grove, Calif
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consider just the definition of pol
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This evidence therefore suggests th
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jurisdiction (“the UNEP Conclusio
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Designation of Particularly Sensiti
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inter alia, internal waters, the te
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ief framework provision on pollutio
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definitions are located in the anne
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Questions arise as to the identity
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opportunity for, or a hurdle to, ad
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145 LOSC in respect of polymetallic
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Seabed Authority) has been establis
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One possibility is the adoption by
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Identification and Designation of P
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Provisions on Ships’ Routeing to
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4. Conclusion This paper has analys
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Instruments adopted under Bonn Conv
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Appendix B - Treaties underlying re
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Appendix C - Selected provisions of
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abate, combat pollution of the Medi
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Annex 2. Guidelines for commercial
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1. Any commercial cetacean-watching
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Annex 3. Documented examples of cet
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Location: Sarasota, Florida, USA Pr
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Beluga whales, Delphinapterus leuca
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These results may indicate habituat
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Location: Northwest Atlantic Northe
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The dolphins started to display eva
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Boats that approached within 30m or
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Location: Hawaii On rare occasions
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Location: Beaufort Sea Aversion beh
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Location: Mexico Gray whale vocal b
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If boats changed their speed or cou
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Corkeron, P.J. 1990. Aspects of the
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Kibal’chich, A.A., Dzhamanov, G.A
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ates of fin whales, Balaenoptera ph
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Annex 4. A note of the Recommendati
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4. the inclusion of anthropogenic n
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Oceans of noise - Whale and Dolphin Conservation Society

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