Mapeamento sonogrÃfico da plataforma continental adjacente ao municÃpio de TamandarÃ, Pernambuco, Brasil




The objective of this study was recognize the actual phisiographic and sedimentologic features of the continental shelf adjacent to TamandarÃ-PE, located in the APA Costa dos Corais through a sonographic mapping. Twenty bathimetric and sonographic profiles had been generated using a Sea Scan PC side scan sonar and an echosounder GARMIN GPSMAP 185 Sounder. These profiles were 500 m spaced and extended beetwen the depths of 15 and 25 m. Twenty six sediment samples had been collected and submitted to granulometric and CaCO3 content analyses. The digital acoustic images obtained by the side scan sonar had been georreferenciated through resample and the patterns of echo and texture, as well as the results of the sedimentologic analyses had allowed to identify three diferents seafloor features. The submarine phisiography of the area was characterized by positive (submerged reefs) and negative (paleochannel) reliefs, intercalated by plain surfaces. Hard bottoms indicates that, during sea-level fluctuations, the shoreline was approximately at 16, 20 and 22 m below of the actual sea-level. The seafloor features (benthic habitats) had been classified as: rocky, muddy and sandy. This last habitat was predominant in the sampling area, being composed mainly by coarse to very coarse carbonatic sands. Muddy habitats had a more restricted distribution, located between the lines of beachrocks observed at depth of 16 and 20 m and mainly near to a smooth depression to the east of the Tamandarà Bay. Rocky habitats represented by âtacisâ and âcabeÃosâ, had occurred in 16, 20 and 24 m depth. The location of these habitats is a contribution to the national and global coral reef monitoring programs. Moreover, in the case of muddy seafloors explored by shrimp fishery, the mapping becomes relevant for stock assessment


plataforma continental side scan sonar oceanografia benthic habitats sonar de varredura lateral habitats bentÃnicos continental shelf

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