Since the end of “easy oil” the fossil fuel industries are driven ever deeper into offshore oil and gas deposits. The industry as a whole contributes a substantial amount of noise to the sea. Seismic airgun surveys are second only to shipping noise in contributing to overall ocean noise pollution .
The surveys are conducted by trawling arrays of airguns behind a ship which explode every 10-15 seconds. The noise permeates the seafloor and the signal that reflects back is deciphered to portray the substrates below.
These surveys can often be heard thousands of miles from the source and are known to disrupt whales and fish in various ways, including killing them. But it is more likely that the common disruptions from airguns are harder to determine – such as degradation to hearing, habitat displacement, stress, and migratory disruptions.
The current global survey fleet includes close to 100 vessels, perhaps half of them working at any time around the world.