Monitoramento da paisagem acústica como serviço aplicado à biotecnologia ambiental marinha

Abstract

Soundscape ecology is a field of study that investigates the anthropogenic, biological, and geological elements that compose the marine acoustic environment. Studies in this area have gained prominence due to the non- invasive characteristics of their monitoring. This study aimed to evaluate the spatio-temporal variability, the influence of anthropogenic, abiotic, and oceanographic parameters, and upwelling on the underwater soundscape in the southeastern coast of Brazil. To do this, acoustic data were collected from Ilha do Cabo Frio, the entrance to Guanabara Bay, Ilha Grande, and the São Sebastião channel. The acoustic data were obtained from the Project for Construction of Signaling Methods with Bioacoustic Noise Characteristics for Underwater Communication (BIOCOM) Project and the Santos Basin Underwater Soundscape Monitoring Project (PMPAS-BS). Acoustic data were used in the range of 125 Hz to 20 kHz, from February 1, 2018 to January 31, 2019. The results found evidenced differences between the sampling points in relation to spatio-temporal analyses. Soundscape patterns from fish, invertebrates, and anthropogenic signals were identified. In addition, the study showed the correlation of the soundscape with the selected parameters and also showed which of these parameters were most representative for each study point through principal component analysis (PCA). The results also showed that northeasterly (E-NE) winds were one of the determining factors for the occurrence of upwelling in the Ilha do Cabo Frio region. Thus, it was found that upwelling influences the soundscape in two ways. From the attenuation of sound pressure levels (SPL) in relation to the rise of cold waters and from the increase in SPL on days preceding upwelling in response to the availability of nutrients for the food chain. In addition, important results were found on water temperature and its influence on the variation of biological signals. These results were shown to be even more relevant in the face of the global increase in ocean temperatures and their recent and successive record-breaking records, caused by the intensification of the greenhouse effect and climate change. Based on the results presented in the thesis, it can be concluded that the information from passive acoustic monitoring (PAM), in addition to highlighting the distinct soundscape characteristics of each region, demonstrated the influence of upwelling on the underwater soundscape. This information can be used to maintain biodiversity and fish stocks.