Long-term trends in ocean noise

• Published in: The Journal of the Acoustical Society of America 2006-11, Vol.120 (5_Supplement), p.3382-3382
• Main Authors: Reeder, D. Benjamin, Pucan, Rommel, Collins, Curtis A.
• Format: Article
• Language: English
• Subjects: Marine
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4781641

The effect of ocean noise, particularly from anthropogenic sources such as Navy sonar systems, on marine mammal hearing, behavior, and reproduction is of great concern. However, relatively few studies exist to make a definitive conclusion regarding rising ambient noise levels, due largely to the dearth of information over sufficiently long time periods for a sufficient number of geographical locations. A few studies have estimated that ocean noise is rising at a rate of approximately 3–5 dB per decade at some frequencies in some locations. This study is based upon ambient noise measurements from U.S. Navy sonobuoys deployed by operational units between 1993 and 2004. Data and analysis are presented for three areas of the ocean—the Northwestern Atlantic Ocean, the Greenland-Iceland-United Kingdom (GIUK) gap, and the Mediterranean Sea. Analysis of this data demonstrates a less significant increase, and in some cases, a decrease, in ocean noise for these three ocean areas at frequencies between 50 and 2000 Hz. Ocean noise levels in this study are comparable to measured ocean noise levels reported in the literature during the 1960’s.