Navegando por Autor "SANTOS, Valdenira Ferreira dos"

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Acesso aberto (Open Access)
Aplicação de dados multisensor (SAR e ETM+) no reconhecimento de padrões de uso e ocupação do solo em costas tropicais: Costa Amazônica, Amapá, Brasil
(2009) SANTOS, Valdenira Ferreira dos; POLIDORI, Laurent; SILVEIRA, Odete Fátima Machado da; FIGUEIREDO JÚNIOR, Alberto Garcia de
Environmental studies require information on land use and land cover. This paper presents the applicability of multi-sensor satellite data (optical and radar) for land use and land cover on the Amapá coastal plain for mapping and recognition of natural and anthropogenic dynamics. This area is influenced by the Amazon River, by tides (tidal bore) and by the Intertropical Convergence Zone (ITCZ). Anthropogenic processes are associated with water buffalo ranching. The environmental information was acquired from previous data and field observation and was correlated with remote sensing data (JERS-1, RADARSAT-1, image from ETM+ sensor from Landsat 7 and DEM SRTM), digitally processed for multi-sensor, multi-scale and multi-date approach. Eight patterns of land use and land cover were identified (mangrove, "várzea" forest, arbustive vegetation area, freshwater marsh, anthropic field, intertidal plain, estuarine channel and lakes) as well with indication of natural and anthropogenic geomorphic features. The results from the evaluation of remote sensing data and the techniques applied demonstrated the potential of the remote sensing tool for studying environments in highly dynamic tropical coastal areas of difficult access. However, these tools may present some limitations once applied to application to the Amazon coast, which is a region under strong dynamic natural and anthropogenic processes.
Acesso aberto (Open Access)
Estratigrafia holocênica morfodinâmica atual da planície costeira da Ilha de Algodoal e Marudá
(Universidade Federal do Pará, 1996-11-08) SANTOS, Valdenira Ferreira dos; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; https://orcid.org/0000-0001-7850-1217
The Coastal Plain of Algodoal and Marudá Island is located on the Bragantina Platform, on the coast of "rias" in the NE of the State of Pará. This plain is limited by the Coastal Plateau, built on Tercio-Quaternary sediments of the Barreiras and Post-Barreiras Formation. Geomorphologically, the Coastal Plain of Ilha de Algodão and Marudá was compartmentalized into 7 morphogenetic units: estuarine channel, beach-dune cords, tidal flat, beach, dunes, salt marshes and "cheniers". This subdivision reveals the existence of a beach-dune string system concomitant with a tidal flat system. The stratigraphic studies allowed the identification of 9 morphostratigraphic units: beach-dune ridges, paleodunes, coastal dunes, beach, supratidal plain, intertidal plain, sandy tidal bar, tidal bar and saline marsh; which in part are related to the morphogenetic units of the plain. 10 stratigraphic facies were also defined: intertidal mud, sand from tidal excavation channels, sand and mud from bars, supratidal plain mud, sand and marine mud, estuarine mud, marine sand, bioturbated silty clay, undifferentiated sediments and sand. mottled. The integration of morphological and stratigraphic data allowed the identification of two stratigraphic sequences: transgressive sequence (S1) with estuarine and beach facing environments and ; regressive sequence (S2) characterized by a beach-dune string system, interdigitated with a tidal flat system. These sequences point to an evolution of this plain within a transgressive-regressive cycle that probably started at the end of the Late Pleistocene. The morphodynamic analysis indicates that the system has been constantly modified in the last 19 years. Waves and tides are the major erosional agents that act in restricted sectors of the coastal plain, while the biggest changes result from coastal accretion to the NE of Algodoal and Marudá Islands. The results of this work show the influence of hydro and aerodynamic parameters (tides, waves, currents, wind and weather), sea level variations and sediment input as preponderant factors in the evolution of the system.
Acesso aberto (Open Access)
Foraminifera, thecamoebians and palynomorphs as hydrodynamic indicators in Araguari Estuary, Amazonian Coast, Amapá State - Brazil
(2010-12) LAUT, Lazaro Luiz Mattos; FERREIRA, Daniele Esteves da Silva; SANTOS, Valdenira Ferreira dos; FIGUEIREDO JÚNIOR, Alberto Garcia de; CARVALHO, Marcelo de Araújo; MACHADO, Odete Fátima
The Araguari estuarine dynamics is singular among traditional models of estuaries under tidal regime due to influence of macrotidal and tidal bore. In order to establish estuarine zones in Araguari according foraminifera, thecamoebians, paliynomorphs and physical-chemistry parameters, sixteen sample stations were established along the estuary. Turbidity and temperature were the environmental parameters which allowed determination of the estuarine gradient. Eighteen species of foraminifera, ten of thecamoebians and fourteen of particulate organic matter types were identified. Cluster analysis in R-mode showed three microorganism assemblages and four palynomorph ones. The CCA analyze shows turbidity and total organic matter with the most influence over foraminiferal and thecamoebians distribution at Araguari. Clustering analysis in Q-mode using all data formed four groups suggesting three estuarine zones in Araguari: Zone I composed of thecamoebian species and continental palynomorphs; Zone II - composed by mangrove foraminifera, thecamoebians and all palynomorph assemblages; and Zone III - composed by mangrove and estuarine foraminifera and all palynomorph assemblages.