Is low frequency ocean sound increasing globally

Low frequency sound has increased in the Northeast Pacific Ocean over the past 60 yr [Ross (1993) Acoust. Bull. 18, 5–8; (2005) IEEE J. Ocean. Eng. 30, 257–261; Andrew, Howe, Mercer, and Dzieciuch (2002) J. Acoust. Soc. Am. 129, 642–651; McDonald, Hildebrand, and Wiggins (2006) J. Acoust. Soc. Am. 120, 711–717; Chapman and Price (2011) J. Acoust. Soc. Am. 129, EL161–EL165] and in the Indian Ocean over the past decade, [Miksis-Olds, Bradley, and Niu (2013) J. Acoust. Soc. Am. 134, 3464–3475]. More recently, Andrew, Howe, and Mercer's [(2011) J. Acoust. Soc. Am. 129, 642–651] observations in the Northeast Pacific show a level or slightly decreasing trend in low frequency noise. It remains unclear what the low frequency trends are in other regions of the world. In this work, data from the Comprehensive Nuclear-Test Ban Treaty Organization International Monitoring System was used to examine the rate and magnitude of change in low frequency sound (5–115 Hz) over the past decade in the South Atlantic and Equato...