Marine Bivalve Sound Detection and Associated Noise Impacts

Bivalves are an abundant and diverse taxon that serve many important ecological roles including ecosystem engineers and biofilters. As largely sessile animals, bivalves have evolved remarkable sensory systems to perceive their mobile and dynamic surroundings, including acoustic stimuli. Yet, the growing presence of human-generated ocean noise may have adverse effects on their sensory abilities, potentially resulting in physiological and fitness consequences. Recent studies have explored how bivalves detect sound and the impact of human-generated noise on their ecology and physiology. However, the vast variety of noise sources and characteristics, along with the limitation of experiments being primarily conducted in tanks, make it challenging to understand the overall impact of noise pollution on marine bivalves in situ. This work provides a brief review of the understanding of bivalve sound detection mechanisms, followed by a collation of noise impact studies to assess trends in noise impact severity relative to amplitudes of sound received by animal subjects. Data from comparable studies of similar sound types and characterizations provide evidence that acoustic impacts tend to be more severe with increasing received levels for both zero to peak particle acceleration (water and substrate) levels (dB re 1 μms−2) and root mean square sound pressure levels (dB re 1 μPa). This suggests that animals closer to a noise source face greater impact severity. Though, more research is needed to clarify these trends, and such data may aid in identifying more robust noise level thresholds among differing impact severities.