Fake Science, Marine Animals and Seismic Noise by Andrew Long, Chief Scientist, Geoscience & Engineering at PGS
Offshore exploration for oil and gas is increasingly confronted by opposition to seismic surveys. For some, the opposition is motivated by an ambition to replace all fossil fuel dependency with renewable energy sources such as solar, wind, geothermal and so on. For others, the opposition is motivated by concerns about the impacts of seismic noise on marine fauna and their habitats. In the latter case there is a wealth of knowledge available on the physics of underwater acoustic noise, but sensational claims are often made about the potential physiological and behavioral effects of acoustic noise on marine animals at various ranges, magnitude and duration. In reality, there has been no documented scientific evidence of noise from air guns used in geological and geophysical (G&G) seismic activities adversely affecting marine animal populations or coastal communities, and the only ‘scientific’ publications that describe physiological damage involved the deliberate firing of air guns in the immediate proximity of marine animals for sustained periods.
The activity of seismic surveys in areas designated as environmentally sensitive is regulated by a series of established ‘received sound metrics’ which include sound pressure level (SPL) and sound exposure level (SEL); together applicable to both impulsive and transient acoustic noise types. Specific SPL and SEL thresholds are used to dictate how surveys may operate at various distances from either observed marine mammals, marine parks, commercial fisheries, and so on. An example of such underwater acoustic thresholds can be found at http://www.nmfs.noaa.gov/pr/acoustics/Acoustic%20Guidance%20Files/opr-55_acoustic_guidance_tech_memo.pdf