Navegando por Assunto "Praias"

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Acesso aberto (Open Access)
Caracterização morfossedimentar durante o ano de 2007 das praias estuarinas da ilha de Cotijuba (Baía do Marajó) no estado do Pará.
(Universidade Federal do Pará, 2008-08-22) OLIVEIRA, Gheisa Karla Martins de; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429
The Cotijuba Island located at 90 km from the mouth of the Pará river is embedded in a tidal zone of the river, where the salinity is zero, and conductivity average is 65.70 μ S. The island belonging to the municipality of Belém is located 33 km of this, with 15 km2 of size and elongated shape in NE-SW direction. The island is supported by: (1) Barreiras sediments, outcroping in the form of exposed cliffs and platforms of abrasion, on the west side, (2) Pós Barreiras sediments, which are above and separated by a erosional surface (SÁ, 1969 apud SANTOS, 1996) and (3) Recent sediments (mangroves, marine terraces, bars and beaches). The study of sedimentmorph characterization of the morpho-sedimentary estuarine beaches of Saudade and Vai-quem-quer during the year 2007 (January, March and August), showed clear seasonal changes of these beaches. They were executed topographical profiles: nine on the beach of Saudade and twelve on the beach of Vai-quem-quer using a Total Station, in addition to the sediments collection. The beach of Saudade is 800 m length and is located on the southern island, with high topographic gradient ranging from tg d = 0,030 to tg d = 0,286. In the northern part of the island is the beach Vai-quem-quer with 1 km in length, which has a gradient topographic trivial compared to the beach of Saudade, ranging from tg d = 0069 to tg d = 0143. Have been applied on these beaches the morphological models of Guza & Inmam (1975), Wright & Short (1984) and Masselink & Short (1993) prepared for ocean beaches. Through the parameters used the beach showed state reflective of Saudade (b = 0.10 to 2.38) and longshore bar and runnel (b = 2.70 to 12.90), during the rainy season and only reflective (b = 0.05 to 1.84), during the dry season of Guza & Inmam (op. cit.). By the measure of Wright & Short (op. cit.) behaved the beach itself as refletiva (g = 1.08 and 0.86 in January and March, respectively, and in August g = 0.43) in the two periods. The beach of Vai-quem-quer presented by the measure of Guza & Inmam (op. cit.) states dissipativo (b = 20.05 to 31.28) and longshore bar and runnel (b = 9.21 to 18.23), in the rainy season. In the dry season, showed the states reflective (b = 1.61 to 2.46) and longshore bar and runnel (b = 2.63 to 3.44). For the parameter of Wright & Short (op. cit.) was classified as dissipative (g = 4.12) in January; longshore bar and runnel (g = 2.64) in March, and terrace of low tide (g = 2.38) in August. The parameter of RTR Masselink & Short (1993) stated that in January the beach of Saudade was influenced by waves and tides (RTR = 5.2) and in March by tides (RTR = 14.5). Already the beach of Vai-quem-quer either in January was influenced by waves (RTR = 2.15) and in March by waves and tides (RTR = 4.80). In the dry period, the two beaches were influenced by waves and tides (RTR = 10.5 and 3.16 for the beach of Saudade and Vai-quem-quer, respectively). The beaches are mostly covered by sand average (65%), moderately selected (59%), with kurtosis mesocúrtica (53%) and asymmetry negative (54%) on the beach of Saudade and approximately symmetrical (43%) on the beach of Vai-quem-quer. There was evidence of seasonality through profiles of acression and erosion, respectively, in dry and wet periods. On the beach of Saudade erosion occurred during the rainy season and acression, during the dry period. This beach has been divided into two sectors: North and South Sector. The South did not present major changes, however in the North Sector was developing a system of ridge and runnel and this has been intense variations with the changes of measures zones of intertidal and supratidal. On the beach of Vai-quem-quer either there was no notable changes during the rainy season. However, in the dry period was noticed acression in zones of upper intertidal and supratidal due to wind influence on the sediments that are at dried in this period. The characterization of the morphosedimentary estuarine beaches of Saudade and Vai-quem-quer is influenced by the Intertropical Convergence Zone (ITCZ), in the rainy season. It intensifies the winds in this period, which reached maximum speed of 7.5 m/s and preferential NE direction, and consequently, formed waves with higher energy (Hb = 1.3 m in January on the beach of Vai-quem-quer) and contributed to the beach erosional process. In addition to the high tides (Hm = 2.9 m in March) who achieved the most internal of these beaches.
Acesso aberto (Open Access)
Diretrizes técnicas e legais para locação de limites edificados em praias
(Universidade Federal do Pará, 2009-07-16) NASCIMENTO, Flávio Campos do; LIMA, José Júlio Ferreira; http://lattes.cnpq.br/5176390429456548
The guidelines for leasing built limits built in beaches borders are important in projects of urban intervention, once, the contention wall has a fundamental role as a limit for urbanization. Contention walls also have the function of to minimizing the effects of erosion and flood in urban areas and to do the support of the necessary embankment for the consolidation of the road system. Drawing from a case study of Praia do Amor (Outeiro, Pará, Brazil), where a design project was completed in 2005, guidelines for the correct positioning of the contention wall in borders of beaches were suggested: i) when defining the limits for intervention, to clearly establish boundaries through photographic, ordnance and topography surveys; ii) assess social, economic and infrastructure demands for an accurate definition of the kind of work to be conducted; iii) assess a diagnosis of buildings information such as shape, occupation, landscape and tenure conditions; iv) conduct climate, hydrologic and ocean conditions for a survey of beach environmental conditions for predicting future impacts on the structure to be built; v) locate the contention wall leaving 50m from the protected area in order to keep built structures away form corrosion; iv) in cases which the limits are already occupied by buildings without possibilities for rearrangement, assess contention wall in order to support the effects of waves and currents to avoid collapses and human and material losses in the area.
Acesso aberto (Open Access)
Eficiência de diferentes abordagens metodológicas e caracterização das associações macrobentônicas estuarinas da zona costeira amazônica
(Universidade Federal do Pará, 2009-06-10) MONTEIRO, Viviane Ferreira; ROSA FILHO, José Souto; http://lattes.cnpq.br/3223362071251898
The estuarine macrobenthic communities from Amazonian coastal regions were characterized using different mesh sizes and sampling depths. The samplings were performed in Algodoal island and peninsula of Ajuruteua (PA), during rainy and dry seasons (June and December 2007, respectively) at the following habitats: mangrove edge, mangrove, sandy and muddy-sandy paths. At each habitat eight biological samples were collected using a cylindrical corer with 0.0079 m², as well as samples for sediment analysis (texture, moisture and organic matter concentrations) and chlorophyll a and pheopigments concentrations. Each biological sample was devided into three strata (0-5, 5-10 and 10-20 cm) and they were sieved on mesh screen sizes of 1.0, 0.5, 0.3 and 0.25 mm. Univariate (ANOVA) and multivariate (MDS, ANOSIM, SIMPER and BIOENV) techniques were used for data analysis. Macrofaunal composition consisted of 68 taxa with dominance of Annelida (Tubificidae and Capitellidae). Meshes of 0.3 and 0.25 mm were the most efficient in terms of retention of organisms and species, while the mesh of 1.0 mm lost significant quantities of organisms, especially Tubificidae. The samples collected at 10 and 20 cm depth did not differ significantly regarding to the number of taxa and organisms. Significant spatial variations were observed on the macrofaunal structure between habitats in both locations and sampling moments, with higher density and richness in muddy paths (mangrove edge and mangrove). The amount of clay, organic matter and moisture concentrations of the sediment were the most correlated environmental variables with the fauna. It could be concluded that: 1. the benthic macrofauna in Algodoal island and peninsula of Ajuruteua was composed by few taxa, and those were typically estuarine and of small dimensions, dominated by Annelida; 2. for characterization of benthic macrofauna is necessary to take samples at 10 cm depth and sieve them on mesh of 0.3 mm size; 3. Muddy-sandy habitats presented normally highest densities and richness; 4. only in Algodoal island was observed temporal variation in the structure of benthic macrofauna; 5. the amount of clay, pheopigments and moisture content in the sediment were the main factors responsible for macrofaunal structure.
Acesso aberto (Open Access)
Encadeamento geoquímico entre sedimentos (solos) e cultivares em praias, além do cabelo humano de ribeirinhos, ao longo de rios da bacia do Purus, no estado do Acre e a sua importância ambiental
(Universidade Federal do Pará, 2005-06-10) MARTINS, Milta Mariane da Mata; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302; https://orcid.org/0000-0002-0134-0432
The state of Acre is located in southwestern Amazonia and are found two biger important hydrographic basins (Purus and Juruá). The rivers have white water and they show U- shaped valleys in the upper regions and with great floodplains in the lower areas. The water of these rivers is low during the dry season displaying beaches (point bars) and diffs. This situation benefits the population of the region who uses these areas for subsistence agriculture, cultivating mostly maize (Zea mays) and beans (Vigna unguiculata (L) Walp), and complementing the diet with fish and meat of both domestic and wild animals. This work attempts to investigate the high fertility of these beaches and mainly the correlation between the sediments (soils) and crops and between sediments and the riparian (hair samples). The main rivers wich constitute the Purus basin were included in the study as the tonws of Sena Madureira (Iaco and Caeté Rivers), Manuel Urbano (Purus River) and those near Acre river valley (Assis Brazil, Brasiléia, Xapuri, Rio Branco and Porto Acre), where beach sediments, beans leaves and seeds, and maize leaves have been studied in 16 stations. The sediments were analyzed by X-Ray Difraction (X-RD) for mineral identification and by MS-ICP. In attempt to verify the concentrations of elements (major and trace elements) such as Ca, Fe, K, Na, Ba, Zn, Mo, Co, Cr, Cu, Pb, Hg, As and Se and their distribution between sediment (soil) and the crops chemical composition analyses were carried out by “água régia” plus MS-ICP and neutron activation methods. The sediments of the beaches are essentially fine with main mineralogy consisting of quartz, clay minerals (smectite, illite and less frequent kaolinite) and feldspars (K-feldspars and albite). The chemical composition shows high concentrations of SiO2, Al2O3 and Fe2O3, besides K2O, Na2O, CaO. The concentrations found are below of the average of earth’s upper crust (except Si2O), however, they are higher than those of beach sediments, and they are similar to those of high fertility sediments and white water rivers. The chemical results for the crops show that the bean leaves show enrichment in Ca and in K the beans seeds. Ba, Zn, Co and Cr are more concentrated in the leaves than in the bean seeds, while Mo is more concentrated in the seeds. As shows significant concentrations in the crops, especially in bean leaves (average of 338,3 ppb) and this is10 times higher than in the seeds. Mercury does not show variation between bean seed (7,7ppb) and leaf (7,1ppb). Selenium is below the detection limit (20ppb). The maize leaves show enrichment in K (average 1,97%), and Ca (average 0,38%). The correlation between sediments (soil) and crops is analysed by coefficient of biological absorption (CBA) that shows decreasing orders of absorption: for beans leaves (Ca > K > Na > Zn >Ba > Co > Cr > Hg > As); beans seeds (Na > K > Ca > Zn > Co > Hg > As); and maize leaves (K > Ca > Cr > Zn > Cu > Hg > As). The distributions may represent the needs of the crops or even the bioavailability of these elements in the beach environment. The high values of coefficients of biological absorption for these elements in the crops reflect the relatively high values of K, Ca, Mg, Zn, Ba and Cr in the sediments and diffs of the rivers of state of Acre, thus proving their high fertility. The low values of Hg in the sediments (soil) that are also very low in crops and the high values of K, Mg, Ca, Zn and Ba transferred to the crops show the efficiency and strong chemical relation with the soil chemistry. They also show that the beach sediments of staee of Acre do not present geochemistry anomalies of neither natural nor human origin, so we can’t say that there is an environment impact. The high values of Hg found in human hair in Manuel Urbano and in part of Sena Madureira cannot be explained by the consumption of bean seeds and maize. A new source should be investigated as a possibility being the carnivorous or fish diets of population. The present study also confirms the empirical knowledge about the beaches properties for subsistence agriculture that the populations that live near the Acre rivers have known for a long time.
Acesso aberto (Open Access)
Estrutura e fisiologia da paisagem da praia do Areião, Ilha de Mosqueiro (Belém-PA)
(Universidade Federal do Pará, 2013-07-04) VIANA, Ivan Gomes da Silva; FRANÇA, Carmena Ferreira de; http://lattes.cnpq.br/5723672412810714
This study has guided the analysis on concept of landscape in systemic perspective and understand there’re elements that interact in complex ways. Areião Beach shows a peculiarity. Thus, the study was made to understand elements that act in southwestern part of the coastal zone of this island, where is located the search area. In one hand, physical elements are analyzed at landscape, such as waves action, wind, tides, vegetation and rainfall, in other hand, the influence of anthropogenic elements are analyzed such as the pier, the effluents and process of using and occupation. Nevertheless, some steps were followed to understand Areião Beach landscape elements in this study. The first step was to create a theoretical-conceptual reference in geography concepts, following the objectives of this work. There’s adopted the classification of Landscape Units proposed by Bertrand (1972). Later it was understood the structure of the landscape, showing the facts of study area on spatial distribution in maps. Four diferent parts were delimited at the beach. After, the seasonality was evidenced by the physiology of landscape and it was highlighted in the analysis guiding interpretations of data variability of morphology and granulometry, as well as their interactions with anthropogenic elements. At this time, the pier’s influence in landscape’s identified. It is believed that pier creates a buffer zone, where tidal action is attenuated to erosional processes that reach the beach. Furthermore, granulometric analysis and the degree of selection showed that there were two sediment transporting cell. The first before the pier, where are the profiles 1 and 2 was located. And the second one after pier, where profile 3, 4 and 5 were located. So Areião Beach was classificated in landscape units. The beach was rated on Geosssistema’s scale, being subdivided into geofacies Ie, IIa1, IIa2, IIa3, IIIe, IIIa, IVa and IVe. At each definition of geofacies we wanted to point, in a spatiotemporal scale of detail, the interrelationship between the physical and anthropogenic active in each landscape unit. The morphology and granulometri data were crossed with qualitative analysis developed through observations in locu to complete the definition.
Acesso aberto (Open Access)
Hidrocarbonetos Policíclicos Aromáticos em Microplásticos de Praias do Litoral Brasileiro
(Universidade Federal do Pará, 2021-07-30) BRANCO, Felipe Ohade Lopes; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
When introduced on the environment, plastic materials might have many destinies, and one of them is the fragmentation. The continue degradation and fragmentation of the plastic materials originates the called microplastics (MP), particles with sizes between 5 mm and 1 μm of a great potential of dispersion. When in polluted environments microplastics tend to become adsorption superficies for hydrophobic pollutants more efficiently than natural solid particles, as Polycyclic Aromatic Hydrocarbons (PAH). PAH are organic pollutants that might have its origin from natural and anthropic processes. In the same way as microplastics, PAH are highly persistent in the environment, and for presenting mutagenic and potential carcinogenic properties when absorbed by human and aquatic organisms metabolisms they are extremely dangerous. Due to its toxic and harmful properties to environment and human health, sixteen PAH are defined as priorities in environmental studies by the United States Environmental Protection Agency (US EPA). Several studies have evaluated the occurrence of microplastics and PAH individually in environmental matrices, but still are few that investigated the association of these two pollutants. In this way, especially in Brazil, there is a need of expansion of research about this theme. The present study has the aim of investigate the occurrence and concentration of PAH in microplastics in beach sediments from eight Brazilian coastal states, to verify its composition and possible sources of the compounds to MP in the studied areas, to relate the accumulation of MP and PAH considering the land use and social-environment factors of each region, and to evaluate the toxic potential and of contamination of PAH from MP to aquatic organisms. Sediment samples were taken from the high tide mark from potentially polluted locals from the beaches of Ver-o-Rio and Farol (PA), Iracema (CE), Boa Viagem (PE), Porto da Barra (BA), Curva da Jurema (ES), Arpoador and Botafogo (RJ), Praia Grande, Santos and São Vicente (SP), and Praia Grande (RS). On the laboratory using a hypersaline solution and a filtration system, MP were separated from the sediments. PAH were extracted using three types of microplastics, 0,2-0,3 g of fragments and pellets, and 0,02 g of EPS (foam), and were analyzed in Gas Chromatography Tandem Mass Spectrometry (GC/MS/MS). It was possible to detect fourteen of the sixteen studied PAH, where the total concentration of PAH (Σ-PAH) varied between 0,25 to 71,60 ng g-1 on the samples and types of MP. On the North and Northeast regions, the low concentration (0,31 to 71,60 ng g-1) of PAH in MP appears to be related to the intense hydrodynamic processes. The concentration of Naphthalene on the foam samples were above the Threshold Effect Level (TEL > 35) on the samples from Pernambuco and Bahia, e near of TEL at Ceará (70,15, 36,97 and 33,28 ng g-1, respectively); so, effects in the organisms might occur due to this compound. The Southeast and South regions are the only that presented previous studies of PAH in MP, so it was possible to make a better comparison and discussion of the obtained data from the present study. The sources of PAH for the environment and consequently for MP were attributed to the anthropogenic contribution (petrogenic and pyrogenic). The highest concentration of PAH was found in the foam samples, suggesting that this type of MP might have a considerable contribution in the dispersion of these contaminants, especially in more polluted locals. Lastly, its concluded that PAH are present on all the Brazilian states studied and its occurrence were evidenced by its adsorption in MP sampled in beach environments. The organic contaminants originate both from petrogenic and pyrogenic processes, and the principal sources of these compounds to the evaluated locals were industrial and port activities, the inadequate disposal of effluents, and the urban runoff by pluvial waters.
Acesso aberto (Open Access)
Variabilidade morfo-sedimentar das Praias Estuarinas do Amor e dos Artistas (Ilha de Caratateua, Pará)
(Universidade Federal do Pará, 2006-06) FARIAS, Daniel Ramôa; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429
The beaches are dynamic and very sensitive, therefore they are formed by sand and gravel that, influenced by meteorologic, hydrologic, oceanographic and anthropic processes, being these responsible ones for the morpho-sedimentary transformations. The studies on the morpho-sedimentary variability of the beaches allows the identification of the places and the periods of greater/minor erosion and deposition in the beaches, that also serve as coastal protection for adjacent ecosystems, urban activities and as habitat for several species of the biodiversity. The estuarine sandy beaches of the Amor and the Artistas are located in the Caratateua island, situated about 30km of Belém, capital of the of Pará state. The Caratateua island is included in the estuarine region of the Marajoara Gulf, under the influence of the Amazonian Equatorial climate (annual rainfall of 2,700 3,000 mm), and with dry (June to November) and wet (December to May) periods, and transitional period (June and November). The tidal amplitude rise to 3,65m - 4,7 m during the neap tides. The study area is developed on the sediments of the Grupo Barreiras and Pós-Barreiras. The monitoring of the morphology and the sedimentology of the transversal profiles of the Amor and the Artistas beaches have been carried during four field stages during 12 months, due to the regional sazonality (2003/2004 – dry, 2004 – rainy. June and, October February of 2004 - transistion). In the Beach of the Amor, three profiles in each stage were executed and one profile in the the Artistas Beach for stage, totalizing 148 sand samples (37 for stage - 10 for profile in the Beach of Amor and 7 for profile in the Beach of the Artistas). The results showns that the beach of the Amor presented an classification of terrace of low tide with small dunes and extensive zone of intermaré (210m), beyond the occurrence of gutters and low declivity (ß=0,95º). Nevertheless, in the beach of the Artistas, is characterized by an reflective beach environment with ~8m high cliffs, an narrow intertidal zone (60m) and high declivity (ß=5,5º). The Amor beach is classified as an Terrace of Low Tide during the dry period (October/2003-2004) and Transversal Chains of Return and Bars during the rainy period (February/2004) and transition (Juny/2004). The Artistas beach is classified as intermediate beach, with two morphologic periods of training: Terrace of low tide, during the dry period (October/2003-2004), while that in the rainy period (February/2004), the intermediate morphologic period of training was of Bank and Longitudinal Gutter, with an presence of zone of intermaré above and banks and gutters, that are located in the zone of intermaré below/inframaré.