Caracterização espacial do fundo marinho da Plataforma Continental Semiárida Brasileira utilizando técnicas de segmentação de imagens de satélite

Abstract

The Brazilian Semi-Arid Continental Shelf (PCSB), a strategic sector of the Brazilian Equatorial Margin (MEB), has attracted growing interest for projects involving the exploration of natural resources and clean energy. However, the lack of detailed information on the geology and morphology of the seabed continues to represent a significant gap in the development of adequate Marine Spatial Planning (MSP). The present study aims to spatially characterize the entire PSB based on satellite images (Landsat 8) and innovative image segmentation techniques. Segmentation was conducted using both pixel-based and object-oriented segmentation models, utilizing the Segment Anything Model (SAM) with ViT-H architecture and the Orfeo Toolbox (OTB). The automatic classification of the extracted vector features w as achieved through the implementation of the Random Forest algorithm. This algorithm was trained using a set of representative supervised samples and spectral attributes derived from prior surveys of the seabed morphology. The results revealed three main geomorphological classes in the PCSB: bedrock, sedimentary features, and fluvial features. Rocky substrates, associated with outcrops and beachrocks parallel to the coastline, indicate areas of high geotechnical stability and may occur in association with sensitive habitats such as reefs and bioconstructions. The sedimentary features, composed of submerged dunes, reveal dynamic environments susceptible to sediment mobility. The fluvial features, represented by ancient valleys and river channels, form regions of morphosedimentary transition, with high geotechnical complexity and paleoenvironmental value. The distinction between these classes, obtained through integrated segmentation and supervised classification techniques, improves understanding of the seabed structure and provides technical information for the MSP, enabling the identification of areas that are more susceptible to erosion processes and have greater biodiversity. These results reinforce the importance of applying modern geoecological approaches to support the planning of more suitable locations for infrastructure installation, supporting MSP actions, minimizing environmental impact, and ensuring the sustainability of marine resource exploitation in the PSB. Keywords: Marine Spatial Planning; Landsat 8; beachrocks; segment anyth