The IQOE will address its five fundamental questions within four themes:

1. The Ocean Soundscapes theme will describe ocean soundscapes from regional to global scales. This theme will include the identification of the primary sound sources and how they contribute to the components of the soundscape, empirical modeling of components of each soundscape, the modeling of acoustic propagation, and the validation of these models using ocean observation systems. This theme will be the main focus of efforts to measure trends in ocean sound levels and to define sound budgets within regions. It will also investigate soundscape diversity and examine the concept that the conservation of soundscapes may be an appropriate objective for the integrated management of the marine environment.

2. The Effects of Sound on Marine Organisms theme will plan and carry out experiments. This may include experiments to make regions quieter and to observe the responses of marine organisms to quieting. This theme will include the use of planned experiments as well as opportunistic studies using post-hoc statistical modeling to test for effects. This theme is the main vehicle through which the biological significance of sound will be assessed and, where possible, this will be focused on estimating dose-response relationships so that assessments of the effects of sound can be predictive, with special emphasis on the Population Consequences of Acoustic Disturbance (PCAD) approach. Much of this theme will rely upon the use of a small set of representative species.

3. The Observing Sound in the Ocean theme will be the primary focus for adding sound measurements to existing and future observing systems and will encourage technical innovation in the measurement of sound. This theme will develop data standards—where these do not already exist—and will promote observation of the key biological and physical variables. Much of the data management needed by the IQOE will be managed from within this theme.

4. The Industry and Regulation theme will develop the methodology for “noise” monitoring within regulatory regimes. This theme will examine the operational management of sound in the ocean through risk analysis by, among other approaches, defining appropriate thresholds for disturbance, damage to marine life, and harm to marine ecosystems. It will also help regulators to measure compliance, and industry to maintain its activities, by providing innovative solutions to barriers presented by regulation. The theme will organize and establish the communications strategy for the IQOE.