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This paper describes the Santos Basin Underwater Soundscape Monitoring Project (PMPAS-BS), a Brazilian ocean soundscape monitoring initiative. The main objective of the project is to quantify and assess hydroacoustic noise of anthropogenic origin in a large sedimentary basin extending from 23° S to 28° S on the southeastern Brazilian continental margin of the South Atlantic Ocean. Noise associated with oil and gas (O&G) exploration and production activities is the primary target, but this oceanic region also has busy shipping lanes for commercial, military, and fishing vessels. The two main hubs of Brazil’s export and import of goods by sea are located in this region: Santos and Rio de Janeiro ports. The project has three measurement components: mobile monitoring based on gliders and drifting acoustic profilers, fixed shallow-water monitoring based on acoustic measurements at coastal stations near shipping lanes associated with exploration and production activities in the Santos Basin, and fixed oceanic monitoring based on deep-water mooring lines equipped with passive autonomous acoustic recorders near production units, shipping lanes, and areas with lower intensity of O&G activities (pristine or reference sites). Numerical modeling of anthropogenic underwater acoustic noise has also been included as a fourth project component. The PMPAS-BS covers an area of more than 251,000 km² and uses several instruments with different methods and sensors for acoustic measurements. Its results provide current sound levels over a very large region of the western South Atlantic, both in areas more and less affected by anthropogenic activities. [ABSTRACT FROM AUTHOR]

Ecoacoustic indices may become an important tool to monitor marine ecosystems because they take passive and non-invasive measurements over wide spatial and temporal ranges. However, the performance and limitations of marine ecoacoustic indices are yet to be fully understood. This study evaluated the Acoustic Complexity Index (ACI), Acoustic Diversity Index (ADI), Bioacoustic Index (H), and Normalized Difference Sound Index (NDSI) in a marine protected area (MPA) named Resex mar Arraial do Cabo in a coastal upwelling in Rio de Janeiro, Brazil. All considered variables, such as water temperature, wind direction, solar radiation, and vessel traffic were monitored from September to December 2018. Principal component analysis showed that the ACI index was negatively correlated with the number of vessels, whereas the ADI and H indices were correlated with water temperature. After categorizing specific moments, the ACI configured the best index for differentiating specific times of day, whereas the ADI was ideal for distinguishing between moments with and without vessel presence. Thus, the ACI and ADI showed the best performance overall. This study identified the main variables influencing the soundscape of a productive upwelling region and intensely used MPA. Furthermore, this research has laid the foundation for further exploration and the development of a robust, non-invasive tool for monitoring marine environments. [ABSTRACT FROM AUTHOR]

A correction is presented to the article "The Brazilian Santos basin underwater soundscape monitoring project (PMPAS-BS)" published in a previous issue of the periodical.