Widespread spatial and temporal extent of anthropogenic noise across the northeastern Gulf of Mexico shelf ecosystem (original) (raw)
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Anthropogenic underwater noise is now recognized as a worldwide problem, and recent studies have shown a broad range of negative effects in a variety of taxa. Underwater noise from shipping is increasingly recognized as a significant and pervasive pollutant with the potential to impact marine ecosystems on a global scale. We reviewed six regional case studies as examples of recent research and management activities relating to ocean noise in a variety of taxonomic groups, locations, and approaches. However, as no six projects could ever cover all taxa, sites and noise sources, a brief bibliometric analysis places these case studies into the broader historical and topical context of the peer-reviewed ocean noise literature as a whole. The case studies highlighted emerging knowledge of impacts, including the ways that non-injurious effects can still accumulate at the population level, and detailed approaches to guide ocean noise management. They build a compelling case that a number of anthropogenic noise types can affect a variety of marine taxa. Meanwhile, the bibliometric analyses revealed an increasing diversity of ocean noise topics covered and journal outlets since the 1940s. This could be seen in terms of both the expansion of the literature from more physical interests to ecological impacts of noise, management and policy, and consideration of a widening range of taxa. However, if our scientific knowledge base is ever to get ahead of the curve of rapid industrialization of the ocean, we are going to have to identify naïve populations and relatively pristine seas, and construct mechanistic models, so that we can predict impacts before they occur, and guide effective mitigation for the most vulnerable populations.
The ambient acoustic environment in Laguna San Ignacio, Baja California Sur, Mexico
Each winter gray whales (Eschrichtius robustus) breed and calve in Laguna San Ignacio, Mexico, where a robust, yet regulated, whale-watching industry exists. Baseline acoustic environments in LSI’s three zones were monitored between 2008 and 2013, in anticipation of a new road being paved that will potentially increase tourist activity to this relatively isolated location. These zones differ in levels of both gray whale usage and tourist activity. Ambient sound level distributions were computed in terms of percentiles of power spectral densities. While these distributions are consistent across years within each zone, inter-zone differences are substantial. The acoustic environment in the upper zone is dominated by snapping shrimp that display a crepuscular cycle. Snapping shrimp also affect the middle zone, but tourist boat transits contribute to noise distributions during daylight hours. The lower zone has three source contributors to its acoustic environment: snapping shrimp, boats, and croaker fish. As suggested from earlier studies, a 300 Hz noise minimum exists in both the middle and lower zones of the lagoon, but not in the upper zone.
The Journal of the Acoustical Society of America, 2008
Repeated ocean ambient noise measurements at a shallow water (110 m) site near San Clemente Island reveal little increase in noise levels in the absence of local ships. Navy reports document ambient noise levels at this site in 1958-1959 and 1963-1964 and a seafloor recorder documents noise during 2005-2006. When noise from local ships was excluded from the 2005-2006 recordings, median sound levels were essentially the same as were observed in 1958 and 1963. Local ship noise, however, was present in 31% of the recordings in 1963 but was present in 89% of the recordings in 2005-2006. Median levels including local ships are 6-9 dB higher than median levels chosen from times when local ship noise was absent. Biological sounds and the sound of wind driven waves controlled ambient noise levels in the absence of local ships. The median noise levels at this site are low for an open water site due to the poor acoustic propagation and low average wind speeds. The quiet nature of this site in the absence of local ships allows correlation of wind speed to wave noise across the 10-220 Hz spectral band of this study.
Marine seismic surveys and ocean noise: time for coordinated and prudent planning
Frontiers in Ecology and the Environment, 2015
Marine seismic surveys use intense (eg ≥ 230 decibel [dB] root mean square [RMS]) sound impulses to explore the ocean bottom for hydrocarbon deposits, conduct geophysical research, and establish resource claims under the United Nations Convention on the Law of the Sea. The expansion of seismic surveys necessitates greater regional and international dialogue, partnerships, and planning to manage potential environmental risks. Data indicate several reasons for concern about the negative impacts of anthropogenic noise on numerous marine species, including habitat displacement, disruption of biologically important behaviors, masking of communication signals, chronic stress, and potential auditory damage. The sound impulses from seismic surveys-spanning temporal and spatial scales broader than those typically considered in environmental assessments-may have acute, cumulative, and chronic effects on marine organisms. Given the international and transboundary nature of noise from marine seismic surveys, we suggest the creation of an international regulatory instrument, potentially an annex to the existing International Convention on the Prevention of Pollution from Ships, to address the issue.
2010
Noise generated by a reef community provides a valuable orientation cue for reef fish; both for larvae as they recruit to reefs, and for adults and juveniles during nocturnal movements. However, the nature of the information conveyed in reef noise is as yet unknown. In this study, the characteristics of daytime acoustic recordings from patch and fringing reefs in the Las Perlas Archipelago, Pacific Panama were compared. Recordings of ambient noise made during the day showed coral reef communities produced acoustic profiles that varied spatially across the Archipelago. At eleven reef sites in the north of the Archipelago, data were also collected on fish and benthic communities using standard visual survey techniques. These data, along with existing survey data from 40 reef sites, were compared with short-term (2 minute) acoustic profiles to explore associations between point sampled acoustic and census data. Using a correlation matrix, the best predictors of acoustic characteristics were identified from a range of factors, including fish density and biomass, coral and fish diversity, coral and algal cover, reef depth and sea state. Multiple regression GLMs highlighted the importance of fish density and diversity on noise below 1 kHz, and coral and benthic diversity on noise above 1 kHz. A positive correlation was also found between coral cover and daytime noise intensity across the entire Archipelago, suggesting potential in the future development of passive acoustics as a method for rapid ecological assessment or for long-term monitoring of reefs. These findings demonstrate the richness of information available to reef fishes, and make the case for further studies that explore the relationships between habitat and community characteristics with temporal and spatial variation in reef noise.
The Journal of the Acoustical Society of America, 2002
Many marine animals use sound and acoustic energy sensors to adapt to their environment. Most biological studies closely examine a particular species' relationship to a specific stimulus. This report examines the fields of research on marine biological adaptations to sound since 1950, assembling an overview of the biological importance of sound in the ocean. It also examines the various sources of anthropogenic noise in the sea with a focus on the potential impacts of that noise on the marine acoustic environment.
Acoustic Masking in Marine Ecosystems as a Function of Anthropogenic Sound Sources
Acoustic masking from anthropogenic sound sources is recognized as a potential threat to lowfrequency specialists such as the baleen whales. Masking from chronic noise sources has been difficult to quantify and measure at both the individual and population levels. There is evidence for increases in low-frequency ocean noise and sound clutter, often in habitats with whale populations. This raises concern that such sound sources could be a chronic factor in the life histories of individuals and populations. This paper presents and extends a recent analytical paradigm focused on masking from vessel noise to include sounds from seismic airgun arrays. The algorithm quantifies changes in an animal's acoustic communication space as a result of spatial, spectral, and temporal changes in background sound levels. The result is both a functional definition of communication masking for whales, and a metric to quantify the potential for acoustic masking. We apply the method to calculate time-varying measures of masking for singing fin whales, singing humpback whales, singing bowhead whales, and calling right whales.