LONG-TERM GOALS

The ultimate goal of this research is to enhance the understanding of global ocean noise and how variability in sound level impacts marine mammal acoustic communication and detectability. How short term variability and long term changes of ocean basin acoustics impact signal detection will be considered by examining 1) the variability in low-frequency ocean sound levels and sources, and 2) the relationship of sound variability on signal detections as it relates to marine mammal active acoustic space and acoustic communication. This work increases the spatial range and time scale of prior studies conducted at a local or regional scale. The comparison of decadal time series from locations in each of the Pacific and Indian Oceans provides the means for quantifying sound levels and variability on multiple time scales in both hemispheres. OBJECTIVES The growing concern that ambient ocean sound levels are increasing and could impact signal detection of important acoustic signals being used by animals for communication and by humans for military and mitigation purposes will be addressed. The overall goal of the study is to gain a better understanding of how low frequency sound levels vary over space and time. This knowledge will then be related to the range over which marine mammal vocalizations can be detected over different tim