What are the energetic costs of communicating in a noisy environment?
Collaborators: Dawn Noren, Ph.D. and Marla Holt, Ph.D. (NOAA), Nicole Thometz, Ph.D. (UCSC), and Terrie Williams, Ph.D. (UCSC)
As the oceans become noisier, animals that rely on sound for communication, finding prey, and detecting predators such as marine mammals may be impacted. Previous research has found that cetaceans modify their vocalizations in the presence of noise – much like people modify their vocalizations in loud restaurants or concerts. Our research team previously quantified the energetic cost of vocal modification by measuring oxygen consumption of vocalizing bottlenose dolphins. These data are now being incorporated into cumulative effects models of disturbance for a variety of cetacean species. While direct measurement of the cost of sound production was possible in bottlenose dolphins, such measurements in other species is more challenging. Instead, we are extending our previous work to other cetaceans using a modeling approach. In birds and terrestrial animals, the energetic cost of acoustic signaling is positively correlated to the proportion of muscle mass devoted to sound production. Thus, we are using computed tomography (CT scans) to estimate the volume of muscle involved in sound production in a variety of cetaceans and using these measurements to scale up our previous direct measurements to other species.
Noren, D. P., Holt, M. M., Dunkin, R. C. and Williams, T. M. (2013). The metabolic cost of communicative sound production in bottlenose dolphins (Tursiops truncatus). The Journal of Experimental Biology 216, 1624-1629.
Holt, M. M., Noren, D. P., Dunkin, R. C. and Williams, T. M. (2015). Vocal performance affects metabolic rate in dolphins: implications for animals communicating in noisy environments. The Journal of Experimental Biology 218, 1647-1654.