Cdr (Dr) Arnab Das
Menu
Ambient Noise
Anthropogenic Noise
Radiated Noise
Marine Species Hearing
Conclusion
Classification
Ambient Noise in the Sea
Classification
Ambient Noise Trend
Anthropogenic Noise
Sonar Transmissions
Oil Exploration
Industrial Activities
Explosions
Radiated Noise of Marine Ves...
Sonar Transmissions
Military Sonar
SURTASS
Towed Array Sonar
Hull Mounted Sonar

Non-Military
Echo Sounders
Side Sc...
Sonar Transmission
Sonar Transmissions
Mid-Frequency Range
Limitation of the Transducer size
Higher attenuation Levels
Localized Impact
...
Oil Exploration
Seismic Exploration
Finding Reserves of Underwater

Oil
Uses High Intensity Sound
Arrays of Air Gun

...
Oil Exploration
Industrial Activities
Dredging
Pile Driving
Underwater Construction
Wind Mills
Power Plants
Canal Lock Operations
Industrial Activities
Some Comparisons
Explosions
Ship Shock Test
To evaluate ability of Ship to

withstand Shock

Chemical Explosion
300-4000 explosions per...
Underwater Explosion
Explosions
Nuclear Explosion
French test as late as 1995-1996
CTBT does prevent such tests in
future however the precis...
Radiated Noise
Ship Generated Noise
Propeller Noise
Machinery Noise
Hydrodynamic Noise

Radiated Noise Spectrum
Narr...
Radiated Noise
Radiated Noise
Low-Frequency Sound
10 – 500 Hz
Undergoes minimal Attenuation
Propagates to a large distance

Distant ...
Radiated Noise
Single Ubiquitous Noise Source
Well Spread out
Low frequency
Minimal Attenuation

Economic Factor
Onl...
Ambient Noise
Shipping the World Over
Machinery Noise
Propeller Cavitation
Propeller Cavitation
CPP Ships
Some Comparisons
What Has Changed?
Some Comparisons
Frequency Response
Hearing Loss-Baleen Whale

Estimated reduction in baleen whale communication range from (left) prior to the
advent of comm...
Fish Hearing
Radiated Noise Spectrum

Underwater radiated noise specification at 11 knots free-running for all
vessels used in fisherie...
Conclusion
Urgent steps required
Awareness.
Actionable Inputs.
Research efforts to understand our

waters.
Challenges...
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013
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Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013

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An understanding of how man created noise affects marine species in the country.

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Anthropegenic noise and its impact on marine species_Cdr Arnab Das_2013

  1. 1. Cdr (Dr) Arnab Das
  2. 2. Menu Ambient Noise Anthropogenic Noise Radiated Noise Marine Species Hearing Conclusion
  3. 3. Classification
  4. 4. Ambient Noise in the Sea
  5. 5. Classification
  6. 6. Ambient Noise Trend
  7. 7. Anthropogenic Noise Sonar Transmissions Oil Exploration Industrial Activities Explosions Radiated Noise of Marine Vessels Acoustic High Power Transmission.
  8. 8. Sonar Transmissions Military Sonar SURTASS Towed Array Sonar Hull Mounted Sonar Non-Military Echo Sounders Side Scan Sonar Sub-bottom Profilers
  9. 9. Sonar Transmission
  10. 10. Sonar Transmissions Mid-Frequency Range Limitation of the Transducer size Higher attenuation Levels Localized Impact High Intensity Sound 230 dB re 1µPa @ 1m Instant Impact
  11. 11. Oil Exploration Seismic Exploration Finding Reserves of Underwater Oil Uses High Intensity Sound Arrays of Air Gun Releases Specified Air at High Pressure Sound Pressure due to Contraction
  12. 12. Oil Exploration
  13. 13. Industrial Activities Dredging Pile Driving Underwater Construction Wind Mills Power Plants Canal Lock Operations
  14. 14. Industrial Activities
  15. 15. Some Comparisons
  16. 16. Explosions Ship Shock Test To evaluate ability of Ship to withstand Shock Chemical Explosion 300-4000 explosions per month reported in North Pacific in the 1960 Used for removal of Undersea Structures and Construction
  17. 17. Underwater Explosion
  18. 18. Explosions Nuclear Explosion French test as late as 1995-1996 CTBT does prevent such tests in future however the precise impact on Marine Life yet to be ascertained Weapon Tests Torpedo firings Tests for Naval Weapon Systems
  19. 19. Radiated Noise Ship Generated Noise Propeller Noise Machinery Noise Hydrodynamic Noise Radiated Noise Spectrum Narrowband Discrete Tonals Broadband Noise due to Cavitation
  20. 20. Radiated Noise
  21. 21. Radiated Noise Low-Frequency Sound 10 – 500 Hz Undergoes minimal Attenuation Propagates to a large distance Distant Shipping Major contributor to Ambient Increased Significantly in the last 30 years
  22. 22. Radiated Noise Single Ubiquitous Noise Source Well Spread out Low frequency Minimal Attenuation Economic Factor Only likely to rise India Emerging as a major ship- building destination
  23. 23. Ambient Noise
  24. 24. Shipping the World Over
  25. 25. Machinery Noise
  26. 26. Propeller Cavitation
  27. 27. Propeller Cavitation
  28. 28. CPP Ships
  29. 29. Some Comparisons
  30. 30. What Has Changed?
  31. 31. Some Comparisons
  32. 32. Frequency Response
  33. 33. Hearing Loss-Baleen Whale Estimated reduction in baleen whale communication range from (left) prior to the advent of commercial shipping to (right) the expected ranges today. Figure courtesy of C W Clark, Cornell University
  34. 34. Fish Hearing
  35. 35. Radiated Noise Spectrum Underwater radiated noise specification at 11 knots free-running for all vessels used in fisheries research
  36. 36. Conclusion Urgent steps required Awareness. Actionable Inputs. Research efforts to understand our waters. Challenges of regulatory framework.

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