Sources of Anthropogenic Sound in the Marine Environment

Anthropogenic sound is created in the ocean both purposefully and unintentionally. The result is noise pollution that is high-intensity and acute, as well as lower-level and chronic. The locations of noise pollution are along well-traveled paths in the sea and particularly encompass coastal and continental shelf waters. Increased use of the sea for commercial shipping, geophysical exploration, and advanced warfare has resulted in a higher level of noise pollution over the past few decades. Informed estimates suggest that noise levels are at least 10 times higher today than they were a few decades ago. A long-term monitoring program is needed to track future changes in ocean noise. Acoustic data should be included in global ocean observing systems now being planned by U.S. and international research foundations. Data from these monitoring systems should be openly available, and accessible to decision makers in industry, in the military, and in regulatory agencies. In tandem, a database should be developed to collect, organize and standardize data on ocean noise measurements and related anthropogenic activities. Currently, data regarding shipping, seismic exploration, oil and gas production, and other marine activities are either not collected or are difficult to obtain and analyze because they are maintained by separate organizations. Marine noise measurements and anthropogenic source data should be used to develop a global model of ocean noise. An important component of model development is better understanding of the characteristics for anthropogenic noise sources such as commercial shipping, arigun arrays, and military sonar. Research should be conducted relating the overall levels of anthropogenic activity (such as the types and numbers of vessels) with the resulting noise.