摘要
In the aftermath of the terrorist attacks on 11 September 2001,a great lull fell over North America,above and below the water.Understandably,fewer people were traveling by air.But ship traffic was also significantly reduced,even as far north as the Bay of Fundy in Canada.As a result,underwater noise in the bay dropped by an incredible six decibels,and sounds at pitches below 150 Hz were significantly reduced.
