Widespread spatial and temporal extent of anthropogenic noise across the northeastern Gulf of Mexico shelf ecosystem

Abstract

The Gulf of Mexico ecosystem represents the intersection between high marine biodiversity and extensive human use and impact. Anthropogenic marine activities are prominent in the Gulf, prompting concern regarding impacts of chronic elevated noise throughout the marine ecosystem. Since sound is a critical component of the marine environment and many marine animals in the Gulf utilize sound in different aspects of their life history, their basic ecology may be negatively affected by elevated anthropogenic noise. While there are data gaps regarding the impacts of noise on marine organisms, it is crucial to understand current ambient noise conditions to evaluate the implications of noise for the Gulf ecosystem. Ambient noise measurements provide a mechanism by which to sample the cumulative acoustic activity of an ecosystem, and holistically evaluate biotic, environmental, and human-induced acoustic contributions to the overall environment. In this study, acoustic data were collected at 7 sites in the northeastern Gulf of Mexico between July 2010 and February 2012. Ambient noise is presented in 3 frequency bands (low frequency [10ñ500 Hz], mid-frequency [500ñ1000 Hz], and high frequency [1000ñ3150 Hz]), with median sound levels of 112, 90, and 93 dB (re 1 µPa), respectively. Abiotic and anthropogenic noise sources significantly contributed to the ambient noise environment; however, seismic survey noise dominated the noise environment and chronically elevated noise levels across several paramount marine habitats. This study describes current noise conditions across the Gulf of Mexico with an intent to inform noise management strategies and investigate the potential ecological implications of elevated ambient noise.