Mapeamento de paisagens submersas no estuário do Rio Pacoti- Costa Semiárida do Brasil.

Abstract

The Pacoti River estuary/CE, located east of the city of Fortaleza/CE, is a protected area created by decree 25.778 of February 15, 2000, by the Ceará state government, with the aim of preserving and conserving the area due to the need to protect this water resource. This environment can be characterized by the formation of sandy bars, with the presence of fluvial and oceanographic processes (waves, tides, winds) responsible for the local dynamics, in addition to anthropogenic factors, such as upstream dams. Located in a semi-arid region, within the Brazilian equatorial margin, these water bodies bring characteristics associated with the seasonal variability of the climate, causing modifications, such as erosion or deposition of sediments, throughout the rainy and dry periods. The modification of the relief creates diverse environments, where there is the presence of organisms with adaptations to these environments. Thus, the objective of this work is to map geohabitats in the estuary of the Pacoti River/CE using acoustic methods (single-beam bathymetry); application of the Benthic Terrain Modeler (BTM) for mapping of benthic zones based on bathymetry data and the analysis and identification of possible geohabitats in this region. The collections were carried out in two periods, November 2022 - dry period, and July 2023 - period after the rainy season, where two bathymetric maps were created, creating 8 channel profiles (E1 to E8) along the river for the study of morphological variation, highlighting the variations in average, minimum and maximum depths and the regions of deposition and erosion present in all profiles. In addition, the bathymetric map is adopted as the basis for BTM modeling. The use of this tool, which is increasingly prominent in the scientific community, identified the zones: transitions (transition), gentle slope (gentle slopes), channel flats (flat channels), coastal slope (coastal slopes), depressions (depressions) for November 2022 and, the zones: coastal slope (coastal slopes), depressions (depressions), slopes (slopes), shallow ridges (shallow ridges) for July 2023. We highlight for the BTM the zone, coastal slope (coastal slopes) that are associated with sandy-muddy banks, regions with macroinvertebrates, such as polychaetes and mollusks, corroborating with mapping of the tool for modeling of these benthic environments, which can be a basis for applications in the face of the need for studies, or even as support for decision- makers, guiding the use of the zones along the APA.