Decadal trends in Indian Ocean ambient sound

Jennifer L. Miksis-Olds, David L. Bradley, Xiaoyue Maggie Niu

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


The increase of ocean noise documented in the North Pacific has sparked concern on whether the observed increases are a global or regional phenomenon. This work provides evidence of low frequency sound increases in the Indian Ocean. A decade (2002-2012) of recordings made off the island of Diego Garcia, UK in the Indian Ocean was parsed into time series according to frequency band and sound level. Quarterly sound level comparisons between the first and last years were also performed. The combination of time series and temporal comparison analyses over multiple measurement parameters produced results beyond those obtainable from a single parameter analysis. The ocean sound floor has increased over the past decade in the Indian Ocean. Increases were most prominent in recordings made south of Diego Garcia in the 85-105 Hz band. The highest sound level trends differed between the two sides of the island; the highest sound levels decreased in the north and increased in the south. Rate, direction, and magnitude of changes among the multiple parameters supported interpretation of source functions driving the trends. The observed sound floor increases are consistent with concurrent increases in shipping, wind speed, wave height, and blue whale abundance in the Indian Ocean.

Original languageEnglish (US)
Pages (from-to)3464-3475
Number of pages12
JournalJournal of the Acoustical Society of America
Issue number5
StatePublished - Nov 2013

All Science Journal Classification (ASJC) codes

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics


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