WETHEY, D. S.*; WOODIN, S. A; University of South Carolina, Columbia; University of South Carolina, Columbia: Secret Sounds of the Sediments: Infaunal Infrasound

Burrowing by polychaetes, bivalves, and other large inhabitants of marine sediments is carried out by a variety of hydraulic mechanisms. We hypothesized that these activities would generate low frequency pressure waves, or infrasounds that propagate through sediments, detectable at some distance from the source. We implanted pressure sensors in intertidal sediments and recorded large amplitude, species-specific infrasound signals. Laboratory recordings of single individuals allowed us to identify characteristic infrasounds of Arenicolid and Nereidid polychaetes, and Tellinid bivalves. In the bivalve Macoma nasuta, there were high amplitude infrasound signals associated with burrowing and with siphon movements. In the polychaetes Neanthes brandti and Abarenicola pacifica, there were high amplitude infrasound signals associated with burrowing and burrow ventilation. These signals were detectable at distances of at least 10 cm. Since the infrasounds are species specific, they may provide a mechanism for predators to detect prey, for prey to avoid predators, for competitor detection and perhaps even mate detection.