Deep-sea sound system: Scientific listening, ocean heat, colonial power

Since the 1970s, oceanographers have used underwater sound to measure ocean heat by means of a scientific technique called acoustic tomography (AT). This article historicizes AT, arguing that both the technique itself and the climatic knowledge it produces propagate colonial, military and capitalist pursuits that are to blame for oceanic warming in the first place. The argument plays out in four parts. Part one situates AT in relation to the discovery of the deep sound channel and Cold War acoustics research. Parts two and three analyse two pivotal AT experiments, namely the Heard Island Feasibility Test (1991) and the Acoustic Thermometry of Ocean Climate experiment (1996–2006). Both experiments were premised on scientific understandings of the deep ocean as ‘nearly transparent to low-frequency sound’, as one oceanographer put it. We term this simplified image of the depths oceanus nullius , after the nineteenth-century legal doctrine terra nullius , which has long been deployed by settler colonists to justify violently expropriating land. We propose instead that the deep ocean should be conceptualized as a loud and sonically dense space – an oceanus maximus – resonating not only with the sounds of ships’ propellers, air-guns and sonar pings, but also with the sonorous tones, clicks, buzzes, grunts and howls of manifold undersea creatures. The article concludes with a discussion of sound’s relation to ambiguity and violence in oceanographic knowledge production.