Navegando por Assunto "Manguezais"

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Acesso aberto (Open Access)
Análise da dinâmica das áreas de manguezal no litoral Norte do Brasil a partir de dados multisensores e hidrossedimentológicos
(Universidade Federal do Pará, 2016-12-16) NASCIMENTO JUNIOR, Wilson da Rocha; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The objective of this research is to analyze the dynamics of the mangrove areas in the north coast of Brazil from images of remote orbital sensors and hydrosedimentological data (flow and suspened sediment concentration). We tried to understand the existence of causality between the expansion or retraction of the mangroves with the suspened solid discharge calculated from the data of flow and suspened sediment concentration. The mangroves were mapped, using the object oriented classification technique, in the years 1975, 1996 and 2008 based on data from microwave sensors (RADAM / GEMS, JERS-1, ALOS / PALSAR). The data of fluviometric stations and sediments of the National Water Agency were used to calculate the solid discharge in suspension in the rivers Araguari, Gurupi, Pindaré, Grajaú and Mearim seeking to relate the addition and erosion in the areas of mangrove with the sedimentary load of the rivers that drain On the coast. The flow variations reflect the precipitation in the sub-basins of the analyzed rivers and presented a strong and moderate correlation with the temperature anomalies on the surface of the Pacific Ocean evidencing a relation of the El Niño and La Niña phenomena with the precipitation regimes in the Amazon. The variations of suspended sediment concentration were not related to the fluviometric variation suggesting that the annual mean oscillations are reflections of other phenomena (coverage and land use). The results show that the drainage areas of the sub-basins most impacted by the anthropic action contribute with a higher sediment load to rivers that have a higher concentration of native forest. Native vegetation contributes to containment of soil erosion and exposed soil and pasture areas are more vulnerable to soil erosion. The Gurupi, Pindaré, Grajaú and Mearim Rivers presented solid suspended load higher than or equal to the Araguari River. Analyzing the mangroves in the estuaries we noticed the addition of mangroves along the estuaries of the Gurupi and Mearim rivers (Baia de São Marcos) and the reduction of mangrove areas in the Araguari estuary. The Amazon coastal zone is subject to natural processes of great magnitude, but atrophic activities influence the natural dynamics of the region by implementing unsustainable economic practices.
Acesso aberto (Open Access)
A aplicação da cromatografia gasosa acoplada (GC-FID), isótopos estáveis, palinologia e razão C:N na reconstituição paleoambiental de manguezais do Estado da Bahia e Espírito Santo.
(Universidade Federal do Pará, 2024-07-30) SILVA, Fernando Augusto Borges da; ALBERGARIA-BARBOSA, Ana Cecília Rizzatti de; http://lattes.cnpq.br/2666263256585897; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
Mangroves depend on ideal geomorphological, geochemical, and climatic factors to develop. Brazil, with its highly indented coastline under tropical and sub-tropical climate regimes, presents suitable conditions for the establishment of these ecosystems and distribution. The dynamics of these mangroves can be influenced by factors related to climatic variations and changes in hydrodynamic flow, resulting in modifications in sediment input and the origin of organic matter. These changes can be observed throughout the Holocene in different regions in of the country. On the northeast and southeast coast, the evolution of these ecosystems is associated with fluctuations in relative sea level (RSL) and sedimentary dynamics, while in the southern region, the change in the distribution of mangroves is a reflection of fluctuations in the RSL and climate changes caused by warming global. Recent studies seek to describe the evolution of these environments based on the elemental and isotopic characterization of organic matter. These constitute important tools in paleoenvironmental reconstruction. However, it is necessary to remember that the comparative analysis of the largest possible number of independent parameters is relevant as it adds value to the research and increases the reliability of the data to be analyzed, generating more precise information. Therefore, aiming to unravel the dynamics of organic matter in mangrove environments, as well as understanding movements of expansion and/or contraction of these ecosystems, analyzes of nalkanes were carried out using chromatography (GC-FID), associated with the sedimentary study, pollen data, isotopic and elemental analyses, synchronized with 14C and 210Pb dating, which allowed obtaining information about past biogeochemical processes and environmental changes during the Holocene and Anthropocene in the coastal plain at the mouth of the Itapicuru river (BA) and at the mouth of the Barra Seca and Jucu rivers (ES). Thus, the results of this research are presented in five scientific articles. The first, see chapter III, deals with the expansion of mangroves at the mouth of the Itapecuru river (BA) during the Anthropocene. The second scientific article (chapter IV) deals with the dynamics of mangroves at the mouth of the Barra Seca River, on the northern littoral of the State of Espírito Santo. The third article (chapter V) discusses the palynology tool used to understand the dynamics of coastal vegetation.The fourth article (chapter VI) presents the environmental changes that occurred at the mouth of the Jucu River, on the central coast of the State of Espírito Santo. Finally, the fifth article presents the results of n-alkanes analyses, compared with isotopic, elemental, palynological data, and 14C dating on the coastal plain of the Barra Seca River.
Acesso aberto (Open Access)
Atributos químicos do solo e composição química de folhas de mangue vermelho (Rhizophora mangle L.) em um manguezal e área transicional em São João de Pirabas, Pará
(Universidade Federal do Pará, 2015) NASCIMENTO, Bruno Delano Chaves do; RUIVO, Maria de Lourdes Pinheiro; http://lattes.cnpq.br/9419564604488031
Mangroves are characteristic coastal ecosystems of tropical and subtropical regions of great social and ecological importance. At Amazon these ecosystems represent more than half of mangrove areas of Brazil (about 70%) and are renowned for their great exuberance and magnitude related to regular distribution of rainfall, high temperatures, the large tidal range (> 4m) and the supply of sediments from the rivers of this region. Changes in water characteristics and physic-chemical soil properties can cause changes in nutrient dynamics in these ecosystems. In transitional environments these characteristics are altered and may have effects on the concentration of nutrients in the ecosystem compartments. In order to differentiate these transitional environments and the actual mangrove environments for the concentration of nutrients, this study aims to determine the nutrient content in the soil, in Rhizophora mangle L. leaves and leaf litter in these two types of environments in two seasonal periods, in a mangrove of the Amazon coast. Samples were collected in the drier month (September 2011) and in the rainy month (April 2012) in the two areas and subjected to chemical analysis for the concentration of macro (Ca, Mg, Na, K, Al, S, P, N, C) and micro nutrients (Cu, Zn, Mn, Fe). We also analyzed the physico-chemical properties of the soil (Eh, pH and salinity) and the granulometry of the ground. The results show higher nutrient concentrations in the fringe mangrove soil when compared to the transition zone (mangrove x secondary forest), indicating that the Eh, which is lower in the first influenced by the proximity to the sea and the highest frequency of flooding by tides, is the main differentiating factor in the concentration of soil nutrients. The nutrients in the Rhizophora mangle L. leaves not differ significantly from one environment to another and do not follow the same pattern of soil concentration on the two areas studied, however, the leaves nutrients are more influenced by the difference of a climatic period for other. Thus, the red mangrove trees of the transition zone can maintain a concentration of nutrients similar to the fringe of the forest, and the structural difference of the woods is more related to soil particle size than the nutritional relationship, since these trees have physiological mechanisms for the maintenance and selection of nutrients, such as N which could be a limiting nutrient in these environments.
Acesso aberto (Open Access)
Avaliação de dados de sensores remotos no reconhecimento e monitoramento de ambientes costeiros tropicais: cabos Cassiporé e Orange, Amapá
(Universidade Federal do Pará, 2006-09-18) BATISTA, Edmilson das Mercês; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
Acesso aberto (Open Access)
O Caranguejo-Uçá, Ucides cordatus, (Linnaeus 1763): da captura à comercialização nas comunidades quilombolas cacau e terra amarela, Ilha de Colares, Pará-Brasil
(Universidade Federal do Pará, 2014-07-10) CARVALHO, Rogério Lopes; QUEIROZ, Helder Lima de; http://lattes.cnpq.br/3131281054700225
This study was conducted at the quilombola communities of Cacau and Terra Amarela, municipality of Colares, Pará State, Brazil. The objective was to describe and analyze the exploitation of the land crab, or mangrove crab (Ucides cordadus), in terms of some socioeconomic aspects, their techniques, strategies and areas of production adopted, and their forms of crab trade. And to compare these aspects with those from other traditional populations also dedicated to the same extractive activity. Semi-open questionnaires, direct observation in the field and trade and flowchart, were techniques applied in this research during 2013. In the communities studied, the extractive economy is predominant, and mangrove crab extraction is among the main activities. At Cacau and Terra Amarela, households have in average 4.3 and 4.9 members, respectively. Most of the families live in their own brickwork houses, built with conventional materials. Despite of this, these extractive households are poor and live in difficult conditions, with almost no access to public services. In general, the inhabitants stop attending school early in their lives, and most of them (72 to 82%) failed to complete the elementary school cycle. A low monthly household income was recorded; the majority of the households earn less than one minimum salary per month. The laço and the braceamento are the main techniques for obtaining the resource. The technique of braceamento is performed during the four days of work per week in average during the rainy months. The application of laço is performed in average during twelve days per month during the drought months. Cacau produces in average 52 (SD ± 15) crabs / work day / person and 110 (SD ± 56) crabs / work day / person in in the rainy and drought periods, respectively. In the Terra Amarela community these averages are 56 (SD ± 24) crabs / day / person and 150 (SD ± 72) crabs / day/ person. The inhabitants of these communities trade with intermediaries from the region. The crabs are sold in natura, whole and alive, transported in cofos in Cacau and bags in Terra Amarela. Are traded at prices that fluctuate throughout the year, from R$ 40.00 to R$ 80.00 each group of 100 individuals. The low pay for they work, together with low education level, deficiencies in infrastructure, low technology for production, and lack of local provision of public services are some of the aspects contributing to the low quality of life of these families in the communities. These factors also contribute for the maintenance of the engagement of local inhabitants in low value activities, such as the extraction of mangrove crabs. The conditions described for Cacau and Terra Amarela are quite similar to those observed in other traditional communities living and working in similar conditions in the coastal region of Pará State, Brazil. The extraction and trade are very similar to most of the traditional communities that exploit this resource in mangroves forests along the coast of Pará. No significant differences or peculiarities were observed in the extractive activity of these quilombola communities, in relation to other traditional populations performing this same activity in the area. However, differences were found between the two communities studied, which represent variations of this general pattern identified. Probably these differences are related to the technologies adopted, and also on the amount of crabs captured in the two locations. These impact the costs of the activity, its profitability, and the quality of life of inhabitants of Cacau and Terra Amarela.
Acesso aberto (Open Access)
Detecção de mudanças na costa de manguezais da Amazônia a partir da classificação de imagens multisensores orientada a objetos
(Universidade Federal do Pará, 2011-03-03) NASCIMENTO JÚNIOR, Wilson da Rocha; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
Mangroves presents great importance to the ecological balance, and a nursery conducive to the development of various animals and plants. In recent years, degradation of mangroves has been occurring more frequently due to the plundering of their natural resources, land planning and poorly planned tourist activities. By remote sensors can map large areas of the area more quickly and efficiently. The objective is to map the distribution of mangrove areas to the east of the Amazon River into the Bay of San Marcos in 1996 and 2008 from remote sensing data. The mapping, change detection and quantification was performed by ALOS / PALSAR, JERS-1, SRTM and Landsat 5 TM. In order to classify the images, we used the software Definiens Ecognition 8, which uses the logic of object-oriented classification. In the classification of the mangrove was an elaborate process tree that stores all the elements or rules (segmentation, algorithms, classes and attributes) needed to obtain the final classification. The result of the quantification of the mangrove was 6705,05 km ² (1996) and 7423,60 km ² (2008) which shows a net increase in mangrove area of 718,55 km ². The change detection map allowed an overall increase of 1931,04 km ², a total erosion of 1212,49 km ², remaining an area of 5492,56 km ² of mangrove unchanged. To statistically validate the results, we elaborated two confusion matrices containing the rights and wrongs of the classification. The error matrix for validation of the classification of classes mangrove swamp, upland, water mass, secondary vegetation, fields and lakes showed an overall accuracy rate = 96.279%, Kappa = 90.572% and 92.558% = index Tau, which showed the classification efficiency of mangroves in relation to other classes used in processing. The error matrix for validation of classification and Non-Change Change of mangrove area showed high accuracy Global = 83.33%, Kappa = 66.10% and 66.66% = index Tau. Therefore, we conclude that the method of object-oriented classification logic is excellent for mapping mangroves and very good for the detection of changes in tropical coastal areas. Regarding the expansion of mangrove areas, it is observed only in the Amazon region, as opposed to what is observed in other large systems of mangroves, such as the Gulf of Papua New Guinea and the Sundarbans in Bangladesh and India. The results were used to compose a mosaic of regional and global mapping of mangrove and ratify the large expanse of mangrove forests in Amazonian Brazil as one of the best preserved of the planet.
Acesso aberto (Open Access)
A dinâmica da vegetação nas planícies de maré do delta do rio Doce durante o holoceno tardio.
(Universidade Federal do Pará, 2019-08-31) CARVALHO, Victor Rocha; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790
The goal of this work was to study the vegetation dynamics on the tidal plain of the Doce River Delta – southeastern Brazil – under the climate change influence and relative sea-level change during the late Holocene (2350 cal yr BP). Thus, 14C dating, sedimentary features, and pollen date, obtained from two cores denominated URU1 (0.5 m depth) and URU2 (4 m depth), sampled with a peat sampler were used. The cores presented four typical sedimentary facies of tidal plain: i) Flaser heterolithic bedding (Hf); ii) Wavyheterolithic bedding; iii) Lenticular heterolithic bedding (Hl) and iv) Parallel mud (Mp). The pollen analysis of URU1 showed herbs predominance, trees and shrubs in all intervals, besides rising of aquatic vegetation towards surface. The URU2 core showed a mangrove and foraminifera influence close to the bottom and middle depth, possibly due to a higher marine/estuarine influence until 2250 cal yr BP. However, close to the surface of this core, occurred a mangrove and foraminifera decrease, followed by freshwater aquatic vegetation increasing, indicating a decrease in the marine influence. This can be a result of a relatively humid climate since at least 2250 cal y BP, which resulted in higher rainfall and flow of rivers. Furthermore, the palynological data shows anthropic or natural alterations that occurred after 2250 cal yr BP demonstrated decreased coverage of palm trees in the tidal plain, further of a higher presence of Cecropia and Typha angustifolia pollen. Therefore, an increase of freshwater flow and wet climate conditions since at least 2000 cal yr BP, has been decisive for increasing sediment transport by the rivers to the delta plain, resulting in a coastline increase, leading coastal progradation, which resulted in replace process between mangroves and herbaceous vegetation.
Acesso aberto (Open Access)
Dinâmica dos manguezais no litoral norte do Espírito Santo durante o Holoceno tardio
(Universidade Federal do Pará, 2018-07-01) SILVA, Fernando Augusto Borges da; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790
This work aims to identify the mangrove dynamics in the North coast of Espírito Santo State, close to São Mateus (ES), during the Late-Holocene, using the depositional identification of paleoenvironments and the paleoflora, further a characterization of the sources of sedimentary organic matter and chronological determination of the events in the study area. In order to perform an integrated analysis of the palynological, C-14 data, sedimentological and geochemical data (δ13C, δ15N, C:N and C:S ratio), two sediment cores (MBN and LI-34) were sampled with a peat core sampler. The sedimentary profiles were extracted from mangroves close to the mouth of São Mateus and Barra Seca rivers. The deposits age was around ~2662 cal yr BP, characterized by sand cross laminations (facies Sc), lenticular heterolithic deposits (facies Hl), sand with parallel lamination (facies Sp), wavy heterolytic deposits (facies Hw), flaser heterolithic deposits (facies Hf and Sf), massive sand (facies Sm), sand parallel laminations (facies Smh facies), and mud with parallel laminations (facies Ml), with shells and vegetal fragments. The first facies association (A) consists of an estuarine point bar (~2662 and ~2215 cal yr BP), the second (B) consists of a tidal flat with mangrove/herbs vegetation, since at least ~2215 cal yr BP, and finally the third (C) such as an inlet, a typical distal estuarine channel (~1337 cal yr BP). The geochemical results indicate a mixture of C3 and C4 plants, near the basal portions, with a subsequent predominance of C3 plants towards the top of the samples, besides the presence of organic matter of marine/estuarine. The C:N ratio indicates an oscillation between the aquatic and terrestrial influences, corroborating the values of the C:S ratio (0.02-5.18), which also revealed a mixture of organic matter with marine/aquatic and terrestrial influence. The pollen results showed that the mangrove in this region has been present for at least 2662 cal yr BP, however, changes in its biodiversity have been observed, since currently this ecosystem is colonized mainly by the genus Laguncularia in the region of the mouth of the Barra Seca river, different from previous periods, where there was full development of Rhizophora and Avicennia trees. However, on the mouth of São Mateus river, the genus Rhizophora beginning the mangrove and after Avicennia. Thus, through of this study, it is possible to infer that there were no significant climatic oscillations in this region, however, the stabilization of the relative sea-level during the late-Holocene, as well as the sedimentary dynamics may be controlling the expansion/contraction process of these mangroves.
Acesso aberto (Open Access)
Dinâmica espaço-temporal e pressões antrópicas em manguezais de RESEXs na costa atlântica paraense.
(Universidade Federal do Pará, 2022-04-26) PEIXOTO, Herbert Junior Campos; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; https://orcid.org/0000-0001-7850-1217
The Atlantic Coast of Pará (ACP) is shelter of the most well-preserved mangrove belt in the world, where some of these areas are included in extractive reserves (RESEX), which provide the sustainable use of its natural resources by the local population. This commitment to sustainability has been gaining strength since the creation of the 2030 Agenda, which gave rise to the Ocean Decade, which seeks the sustainable and scientific development of marine and coastal resources. Thus, the objective of this study is to analyze the spatio-temporal variability of mangroves inserted in the RESEX of the PCZ. The adopted methodology consists of: (1) acquisition and processing of images from Landsat satellites (2) quantification and comparison of the mangrove areas of four RESEX (Mãe Grande de Curuçá, Mestre Lucindo, Mocapajuba and São João da Ponta). These analyzes were carried out using polygons, created from Landsat satellite images, which delimited the mangrove areas for a period of thirty-four years (1986 to 2020). Using the mapbiomas collection plugin, available in the QGIS software, it was possible to observe urban sprawl in the studied areas and their interaction with mangrove environments. To corroborate the results obtained, environmental data of suspended particulate matter (MPS) were used. The vegetation cover had the highest reduction value of 8,054 km² and maximum increase value of 14,825 km². It was possible to observe patterns of variation in the RESEXs, which showed similar trends, both in terms of loss and gain in area. Little change occurred in the mangrove areas in the innermost portions of the RESEXs. The suspended particulate material (SPM) transported in the region has SW NE direction. It was also possible to observe the growth of urban infrastructure in all municipalities where the RESEXs are located, with Marapanim and Curuçá showing the highest growth (4,642 km² and 4,797 km², respectively). However, most changes in mangrove cover occurred along the coastline, far from urbanized areas. The analyzed mangroves remained in balance; however, disorderly urbanization can bring losses if there are no effective measures.
Acesso aberto (Open Access)
Duas décadas de mudanças dos manguezais de meso e micromarés do litoral brasileiro a partir de imagens multisensores
(Universidade Federal do Pará, 2020-05-25) LOPES, João Paulo Nobre; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252; 3282736820907252
Mangroves are coastal environments that extend along the tropical and subtropical global coastal regions, whose constant monitoring is hampered by its large-scale distribution. With the advent of new computational technologies supported by remote sensing (Google Earth Engine - GEE), this problem has been partially solved. However, some limitations still persist, for example, the use of an image library using only optical sensors, making it difficult to map mangrove forests in areas frequently covered by clouds. Thus, this work aims to evaluate the classification and changes in the mangrove areas of the meso and micro-tidal regions of the Brazilian coastal zone in the last two decades through multi-remote sensor data (optical and microwaves) from geographic object-based image analysis (GEOBIA). Multitemporal images from the Landsat, Alos PalSar, JERS SAR and SRTM series were used. The remote sensing dataset were processed according to the GEOBIA approach, which determines the reduction of an image in homogeneous regions (objects) by grouping sets of pixels with similar characteristics. As a result, it was observed that in 1996 and 2016 the area under study contained 2625,38 km² and 2898,26 km² of mangrove areas, respectively. This demonstrates an increase of 273 km² in mangrove areas. From the analysis of the change detection, it was observed a total increase of 684.55 km², a reduction of 411.7 km² and an unchanged area of 2213.70 km² of mangrove. The classification was validated through statistical analysis of two error matrices (2008 and 2016). The 1996 error matrix presented overall accuracy = 0.92; Kappa index = 0.84; and Tau index = 0.84. For the year 2016, overall accuracy = 0.93; Kappa index = 0.85; and Tau index = 0.85. On the other hand the error matrix for change detection showed an overall accuracy of 78.43%, with a quantity disagreement of 11.86% and an allocation disagreement of 9.71%. Quantifications of mangrove loss was 414 ± 43 km², gains was 590 ± 48 km² and remained mangrove unchanged was 2305 ± 60.3 km². These results demonstrate the effectiveness of using object-oriented classification for mapping and analyzing mangrove dynamics on a large scale. The products obtained in this research can serve as a basis for future work on the dynamics of mangroves, contributing to the improvement of management and preservation of this important ecosystem.
Acesso aberto (Open Access)
Efeitos das variações sazonais do clima tropical úmido sobre as águas e sedimentos de manguezais do estuário do rio Marapanim, costa nordeste do Estado do Pará
(Instituto Nacional de Pesquisas da Amazônia, 2008) SILVA, José Francisco Berrêdo Reis da; COSTA, Marcondes Lima da; VILHENA, Maria do Perpétuo Socorro Progene
To evaluate the short period climatic variations impact over Amazonic mangrove ecosystem, studies were carried out on the northeast coast of Para State. Sediments, surficial and interstitial waters were collected and examinated throughout salinity, pH and Eh (mV) measurements; mineralogical determination using X-ray diffraction and electronic microscopy. Chemical analysis of dissolved sulfides, sulfate and chloride, among others were made in samples collected seasonally, under spring and neap tides conditions. The seasonal chloride variations in the interstitial waters shows 20 g/l during the dry season and less of 10 g/l in the season; the concentration in surficial are higher at neap tides (rainy season) and spring tide (dry season). The dissolved sulfides were found only at 10 cm, indicating sediment exposure to the atmospheric oxygen advectives fluxes. The dissolved iron rates increases between 0-10 cm and the pH tends to neutrality. The saturation of interstitial waters at dry season is indicated by evaporitic minerals: gypsum and halite. The pluviometric variations are responsible by gradual changes in the nutrient and physical chemical properties of surficial and interstitial waters, into the saline equilibrium control at coastal waters, in the salinization and desalinization of sediments and the distribution of mangrove vegetation at the estuary. The prolonged exposure of sediments during the dry season and the morphological characteristics contribute to the total or partial oxidation of surficial sediments, modifying the mineralogy of sediments and the physical chemical characteristics of interstitial waters.
Acesso aberto (Open Access)
Estudo geoquímico e biogeoquímico de água intersticial, sedimento e árvores de Avicennia Germinans do manguezal de Bragança – Ajuruteua, NE do Pará.
(Universidade Federal do Pará, 2001-06-06) LEAL, Helenice Ferreira; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
Acesso aberto (Open Access)
Evolução dos pântanos da região central da península de Bragança-PA de acordo com as mudanças do nível relativo do mar durante o holoceno
(Universidade Federal do Pará, 2016-12-07) CAMARGO, Paloma Maria Pinto; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
This work integrates data from geomorphology, sedimentary features, pollen, diatom, isotopes, mineralogy, chemical analysis and C-14 datings obtained of sediment cores sampled from Bragança Península, Pará littoral. The pollen data indicate that central and topographically higher area of Bragança Peninsula was an area dominated by mangroves, with wide expansion of Avicennia trees, marine diatom, an increased trend of sedimentary organic matter sourced from estuarine algae, and a mineralogical composition mainly formed by pyrite and hematite, typical of mangrove anoxic sediments between > 6300 and 4900 cal yr BP. Between 4900 and 4300 cal yr BP occurrs a without pollen zone, but along this interval takes place marine diatom, an increase of sedimentary organic matter sourced from marine algae and the absence of minerals formed by Fe and S. In the late Holocene (<4300 cal yr BP), the study site was recolonised mainly by herbs with Avicennia trees restricted to border of the herbaceous plain, presence of freshwater diatom remains and a significant increase trend in contribution of sedimentary organic matter of terrestrial origin (C4 plants). Precipitated minerals from enviroments under intense evaporation form the mineralogical composition. In recent decades, there is a mangrove migration to elevated surfaces occupied by herbs (C4 and C3 terrestrial plants), and an increase of sedimentary organic matter sourced from estuarine algae. An upward increase in the Sr concentration occurs along the last 10 cm. These data suggest a mangrove and salt marshes dynamic mainly controlled by the relative sea level changes. Probably, postglacial sea level rise contributed to the establishment and expansion of mangroves in the Bragança Peninsula with great impact on the expansion of Avicennia trees and marine diatoms, an increase of sedimentary organic matter sourced from estuarine algae. This environment favors the mineral precipitation for instance of pyrite. Between 4900 nd 4300 cal yrs BP, the continuous relative sea level rise causes the increase of marine/estuarine diatoms and the contribution of sedimentary organic matter sourced from marine algae. However, it caused the drowning of mangrove and associated vegetation, and consequently its disappearance from the study area, as well as the environmental conditions for sulfides precipitation. After 4300 cal yrs BP, the increase of sedimentary organic matter sourced from C4 terrestrial plants and freshwater diatoms suggest a relative sea level fall. The mineralogical composition suggests an arid environment, such as a sabkha. This process caused the recolonization of herbs (mainly C4 plants) in the topographically highest area of studied peninsula and Avicennia trees surrounding this herbaceous plain. Considering the last decades, the Avicennia trees migration to elevated herbaceous fields, the increase trend of organic matter sourced from estuarine algae and the increase in concentration of Sr during the last 10 cm suggest a modern relative sea level rise.
Acesso aberto (Open Access)
Fragilidade ambiental na bacia do rio Mocajuba - PA
(Universidade Federal do Pará, 2020-02-17) CAVALCANTE, Juliane da Costa; LIMA, Aline Maria Meiguins de; http://lattes.cnpq.br/6572852379381594; https://orcid.org/0000-0002-0594-0187
The hydrographic basin of the Mocajuba River has been densely occupied by the expansion of human activities. In this way, anthropization jeopardizes the permanence of the natural ecosystems and mangroves in this region. In this context, this work presents the dynamics of the landscape in the Mocajuba River basin between 1999 and 2018 and its implications for the natural fragility of the basin and the continuity of the mangroves in this region. To this end, the research is divided into the following items: (1) Analysis of land use and land cover in the hydrographic basin of Rio Mocajuba - PA, using the Object Oriented Classification (GEOBIA) and the Google Earth Engine platform as methods (GHG), in conjunction with the Random Forest classifier. (2) Application of the Potential and Emerging Environmental Fragility methodology, using natural data from the basin (pedology, geological units, altimetry and rainfall) in conjunction with anthropogenic data (land use and cover). (3) Temporal analysis of the mangroves in the basin between 1984 and 2018, observing the expansion and regression of this ecosystem, as well as the anthropic and environmental tensors to which they are susceptible. The land use and land cover classification methodologies presented different quantifications and accuracy. For 1999, the GEOBIA and Random Forest classification presented a Kappa coefficient of 0.79 and 0.92, respectively. For 2018, the coefficient was 0.73 and 0.8, respectively. For both methodologies, the class of Forestry Formation suffered a decrease and Non-Forestry increased. For the Mangrove class, the GEOBIA classification quantified an increase and the Random Forest decrease. In the environmental fragility methodology, the levels of potential and emerging fragility obtained were low, medium and high. Where 19.92%, 76.67% and 3.41% of the basin showed low, medium and high potential fragility, respectively. For emergent fragility, the mangrove and non-forest areas increased the natural fragility of the basin and the forest formation class provided an attenuation of this. In this case, the areas of low, medium and high emerging fragility were quantified at 18.39%, 67.57% and 14.04%, respectively. Mangrove areas decreased between 1984-1999 and 1999-2018. The data presented confirm the expansion of the anthropization of the basin and the interference of human activities in the dynamics and response of the mangroves in the face of natural tensors. As confirmed by the increase in the natural fragility of the basin provided by the expansion of these activities. In this way, the research becomes relevant for providing a systemic analysis between different areas, seeking to understand the functioning of the basin ecosystem, assisting in future research and initiatives.
Acesso aberto (Open Access)
Geoquímica dos sedimentos de manguezais do nordeste do estado do Pará: um exemplo do estuário do rio Marapanim
(Universidade Federal do Pará, 2006-01-20) SILVA, José Francisco Berrêdo Reis da; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
The northeast coast of Pará state was geologically built on fluvial valleys partially submersed during the Holocene, where the mangroves of Marapanim estuary were developed. Adjacent to the mangroves, iron sediments and Latosol of Barreiras Formation (Tertiary) are the main source of silt, clays and sands. Despite the ecological, social and economic mangrove significance, there is a lack of geologic information focusing the processes and the magnitude of mineralogical and geochemical transformations occurring in these ecosystems on the Brazilian north coast, which is the main goal of this research. To reach the purposed objectives topographic studies were run, as soon as a short description about the mangroves. Sediments were sampled in the end of both rainy and dry seasons and submitted to in situ interstitial salinity, Eh and pH measurements. To these samples were also run chemical analysis to determine SiO2, Al2O3, Fe2O3, TiO2, P2O5, Na2O, K2O, CaO, MgO, L.I. (lost on ignition) and granulometric analysis. Trace elements were determined by using ICPM-MS; minerals were determined by using X-ray diffraction and SEM techniques. Surface and interstitial water were sampled during neap and spring tides, in periods with both higher (March, June and July) and lower (September, November and December) pluvial precipitation. These samples were submitted to chemical analysis to determine H4SiO4, SO4 2-, ΣH2S, NH4 +, Cl-, PO4 3-, Na+, Mg2+, Ca2+, K+, total alkalinity and dissolved iron. Salinity, Eh and pH were also measured. The mangroves are typically from intertidal zones and are represented by a mixture of Rhyzophora mangle and Avicennia germinans developed under semidiurnal macro tides, totally submersed during the ebb-tides and weekly exposed during the spring-tides, under a rainy tropical weather, hot and humid with remarkable climatic seasonality. The mangrove sediments are predominantly silt-clayed, rich in organic matter (C: 1 to 4% grade). Those sediments were originally deposited over sand bars, which smooth morphology and sedimentological aspects promote vegetal colonization, drainage network evolution and sediments development, increasing its consistency. The tropical chemical weathering acts over the source areas producing quartz, low crystal kaolinite grains, iron oxides and other dissolved chemical substances like silica, aluminum and heavy metals which are incorporated to the mangrove sediments, with diatoms and Na+, K+, Ca2+ e Mg2+ ions from marine contributions. At the mangrove, the original material is reworked throughout intensive biological activity and geochemical processes developed in the presence of different organic matter grades and the reactive surface of biogenic silica (diatoms), originating minerals in total or partial equilibrium within the new conditions. The autigenic minerals are pyrite, smectite, K-feldspars, halite, gypsum, jarosite beyond quartz and remobilized iron oxy-hydroxides. Mangrove sediments present high grades of dissolved sulfide ions (6 to 40 mmol/L) while in depth, sulfate ions are consumed. Dissolved sulfide is formed from organic matter mineralization under bacteriological sulfate-reduction, which final product is the pyrite. In depth, total dissolved iron grades are reduced close to zero due to the reaction with part of the dissolved sulfide to form solid sulfide (pyrite). This reaction occurs in an extremely reductor chemical environment (-200
Acesso aberto (Open Access)
Hidrodinâmica e transporte de sedimentos em uma área de manguezal na planície costeira de Bragança, Amazônia Oriental – Brasil
(Universidade Federal do Pará, 2012-10-04) MIRANDA, Artur Gustavo Oliveira de; ROLLNIC, Marcelo; http://lattes.cnpq.br/6585442266149471; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
The physical processes that occur in intertidal areas are essential for the existence of mangrove ecosystem, due process interaction between oceans and estuaries, with mangroves. The tidal channels represent the most important and peculiar features of coastal environments, due your circulatory system basics which controls both the tidal flow as the channel morphology. This paper presents a set of data to analyze and understand the hydrodynamic process and sediment dynamics in the coastal plain of Bragança, specifically the region known as Furo do Meio tidal channel. At this region were carried out topographic and hydrodynamic collection of data, physicochemical properties of water measurements, surficial sediment collection, and quantification of sedimentation rate according the seasonality pattern (March, July, September and December). As this study demonstrated, the tidal channel presented a well defined bidirectional flow, though the area vegetated by mangrove presented a turbulent flow, so the variation of current speed in both morphological units vary according to seasonality. The average concentration of suspended solids (CSS), between the months from March to September, remained at around 400 ppm in the channel. To the tidal flat dominated by mangrove forest, an average of approximately 21,000 ppm was obtained, while in the month of December, these values were lower than those recorded in previous months, where the maximum CSS in the channel was around 270 ppm and in the mangrove was 1000 ppm. There was not a direct relationship between the CSS and the mangrove channel, where high CSS in the mangrove is associated with the remobilization of the sediment itself at tide input in this area; there was not a significant sedimentary input of mangrove to the channel. Changes in topographical elevation corroborates the values obtained in measurements of trappers and the variation of sedimentary textural classes between fine silt and fine sand are associated with the seasonal hydrodynamic variation.
Acesso aberto (Open Access)
Imaginário, trabalho e sexualidade entre os coletores de caranguejo do salgado paraense
(Universidade Federal do Pará, 2014-12) SILVEIRA, Flávio Leonel Abreu da; SOUZA, Camilla da Silva
In this work we propose to discuss the relationship among imaginationy, work and sexuality, from the activities of crab pickers that live in the bragantina region, called Salgado Paraense. The aim is to link such themes to the enchanted figure that inhabits the mangroves where the people pick the crustaceans called Ataíde, as well as to discuss the sexual acts between people of the same sex, in this case, involving the masculine universe.
Acesso aberto (Open Access)
Morfologia e mudanças costeiras da margem leste da Ilha de Marajó - (PA)
(Universidade Federal do Pará, 2003-02-27) FRANÇA, Carmena Ferreira de; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429
The eastside of the Marajó Island (Pará State) shows a diversity of morphological features produced by sea level changes, neotectonic and coast dynamics, during Late Cenozoic. The sea level changes, from Miocene to Holocene, controled the deposition of Barreiras Formation and Pós-Barreiras Sediments that form the coastal upland. The framework neotectonic structures controll the NE-SW strip-slipe fault systems and NW-SE normal faults, influencing the distribution of relief units and the fluvial and shoreline morphology. The coastal morphology shows two main units: coastal upland and coastal plain. Coastal upland represents a flated relief with low ondulations and elevations between 5 and 15 meters. The contact with the coastal plain is abrupt, forming “dead” and active cliffs. The coastal plain has a flat relief with low gradients, with portions below 5 meters in hight, which favors sea inundations and the sedimentary dynamic. Long term coastal changes, during the last 5.000 years, resulted in shoreline accretion in response to regressive or stable sea level conditions, with the development of tide flats and mangroves, with migration of barrier-beaches and dunes over mangrove deposits. The accretional and regressive successions of the Soure coastal plain is agreeable to the regressional succession (S2) and transgressive succession (S3) as proposed to coastal plains of Bragança, Salinópolis, Marapanim and São João de Pirabas. The medium term coastal dynamic (1986/2001) is represented by morphological changes in response to interactive action of wave, current, tide and wind process, which has produced changes in the shoreline position. Soure and Salvaterra coast has been submited, in the last 15 years, to erosional processes characterized by shoreline retreat. The total of erosioned lands reached from 0.89 km2 (1986/1995), to 0.38 km2 (1995/1999) and 0.75 km2 (1999/2001). While the accretional areas represent a total of 0.21 km2 (1986/1995), 0.32 km2 (1995/1999) and 0.08 km2 (1999/2001). The short term coastal changes involve the morphological and textural variability from beach topographic profiles in the rain and dry periods seazon in 2001. The seasonal changes are reflected in answer from the beach profiles in respose to variations of tides, ranges of currents, wave energy, availability of sediments and coastal morphology. In Soure, the erosional phase (february to april rainy period with highest tidal range) when it is possible to observe the shoreline retreat (21 m), backshore reduction (13 m), parallel dislocation of foreshore, sedimentary loses, granulometric coarsing (2.81 to 2.94 ϕ, thin sand)) and better selection (0.24 to 0.33, very well selected). The accretionary phase (july to nevember, dry period with stronger winds) showed: hight tide line extension (82 m), backshore enlargement (48 m), sedimentary gain (+339.25 m3), granulometric finning (2.86 a 3.10 ϕ, thin to very thin sand) and worse selection (0.28 to 0.40, very well to well selected). In Salvaterra, the accretional phase (february to april) showed high tide line extension (29 m), backshore enlargement (13 m) and raise of beach volume. In profile 1, there was a granulometric coarsing (0.84 ϕ, thick sand) and worse selection (0.51, moderatelly selected). In profile 2, the grain became thinner (1.49 f medium sand) and better selection (0.44 well selected). The erosional phase (july to november) showed high tide line retreat (25 m), diminution backshore (8 m), sedimentary loses (-22.69 m3), exchange of material between the higher amd lower part of the profiles, the grain became thinner (1.39 ϕ medium sand) and worse selection (0.52 moderatelly selected). The vulnerability of the coast zone to natural risks occur in response to erosive processes in the last 15 years. The environmental zonement resulted in an integration of morphological dates with analysis of coastal changes geoindicators and human interference levels. Different sectors of the coastal zone were classified in : permanent preservation areas (mangroves, beaches and dunes), adequated to occupation areas (coastal upland), areas with risk to occupation (cliff sides) and environmental damage areas (deforested mangroves, beach-dune ridges occupied). The recomendations of preservation, use and future occupation from the coast should subsidize the planning and coastal management. The use of remote sensing and of Geographic Information System, in the several stages of this thesis development, represented important tools to data aquisitions, spatial analysis and synthesis, understanding of coastal relief distribution and caracteristics, observation and quantification of the changes, thematic mapping. Thus this information presents a large use in coastal studies.
Acesso aberto (Open Access)
Percepção dos gestores de reservas extrativistas marinhas sobre os efeitos das mudanças climáticas no salgado paraense - Pará-Brasil
(Universidade Federal do Pará, 2021-08-24) BECERRA RUIZ, Melgris José; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685; https://orcid.org/0000-0001-6045-0984; PIMENTEL, Márcia Aparecida da Silva; http://lattes.cnpq.br/3994635795557609; https://orcid.org/0000-0001-9893-9777
Climate change is an issue that, since the last century has gained interest among scientists around the world, there are many information that have been turned to address this issue from different fronts, however, the perception of local communities is far away to be one of the most successful work topics. Brazil has a network of Extractive Reserves (RESEX), which is part of protected natural areas and where environmental managers participate who exercise control, monitoring, implementation of projects that serve as a basis for the conservation of RESEX, as well as a contact direct with local communities. Many mangrove ecosystems are concentrated in the RESEX of the Paraense coast. Around these ecosystems, traditional communities have settled that make use, enjoyment, and enjoyment of them, which have incorporated into their daily activities offered by the mangroves, which ranges from leisure, pleasure, and enjoyment to the generation of income to maintain the lifetime. In this sense, in this work the coastal region of the north of Pará was approached, the so-called Salgado Paraense with the aim of knowing the perception of local actors and the effects of climate change in this territory. To achieve this objective, the work was carried out in two phases. A first study was carried out to find out the amount of published bibliography on the perception of climate change around the world, in three main languages such as Spanish, English and Portuguese. For this bibliographic analysis, we applied natural language and machine learning to analyze more than 30,000 scientific articles. Some maps were produced on study trends, countries with major researchers interested in this topic, the methodologies used, and the approaches taken to understand the effects of climate change. Subsequently, in the second phase, surveys were applied to the environmental managers of the RESEX studied, to know their perception of climate change, interest in the adoption of adaptation strategies in the face of climate change and their perception of the role of the women in social dynamics within RESEX in the face of climate change threats. The findings suggest that studies on the perception of climate change in the coastal communities of northern Pará are necessary and have a lot of potential for their research, since the interested actors really have an affinity in adopting measures against the impacts of climate change, they show their concern about the effects on communities and mangroves, generating an alert and a call to incorporate local populations with more interest in the design and implementation of adequate and pertinent public policies. It is necessary that the actors of organized civil society, community, managers, and governments at different scales understand that the challenges are increasing to face climate change, this situation is worrying in various parts of the world, it is therefore, necessary to incorporate the vision of local communities.
Acesso aberto (Open Access)
O potencial do sensoriamento remoto SAR no mapeamento, discriminação de gêneros e estudo da dinâmica de floresta de mangue na região Amazônica.
(Universidade Federal do Pará, 2019-04-26) COUGO, Michele Ferreira; FERNANDES, Marcus Emanuel Barroncas; http://lattes.cnpq.br/8943067124521530; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
This dissertation examines the potential of data generated from SAR sensors to differentiate between mangrove genera using polarimetric data, biomass estimates based on forest structure, and by producing thematic mangrove forest maps, using multi-frequency SAR images. Polarimetric SAR data (Radarsat2), multi-frequency (bands X, C and L) were used to achieve this goal. The study area is the Ajuruteua Peninsula, located in the eastern sector of the Amazon Coastal Zone. Mangroves in this region are considered preserved with the following species present: Rhizophora mangle, Avicennia germinans, Avicennia schaueriana and Laguncularia racemose, where R. mangle is the dominant species in this region. Through the polarimetric image Radarsat-2, band C, the polarimetric response of the parcels, dominated by these two principal genera (Rhizophora e Avicennia), were analyzed. Through the analysis of the polarimetric response, we were unable to define a pattern per genus to allow for the differentiation of the genera using this parameter. Analysis of the scattering mechanism was conducted through polarimetric decomposition of the coherence and covariance matrix. In the H-α plane, all vegetation parcels were classified as zone 5 of average entropy, attributed to vegetation scattering, and as zone 6, also of average entropy, associated to an increase in the surface-level roughness. Only the field class presented an H value lower that the other classes, standing out from the others. The images of scattering mechanisms: double-bounce, volumetric and surface-level did not permit the separation of dominant genera in the region. Using annual time series images Sentinel1-A, the behavior of the σ° polarizations VV and VH were similar and did not present differences in relation to total biomass values. Variations in radar backscatter over the year were related to environmental conditions (precipitation and tidal regime), canopy alterations (phenology) and incidence angle. The σ° values were greater during the month of May to the end of August, and in the same period, σ°VH/σ°VV rate values were lower, which is a reflex of mangrove canopy dynamics in the region given that during this period leaf litter production is greater, despite modest oscillation (1.5 dB). The use of multi-frequency SAR images for Random Forest classification of the environments on the peninsula resulted in the best Kappa index, 0.53, for the model that included the Sentinel1-A and ALOS-PALSAR images, with a Kappa mangrove class of 0.90. The dwarf mangrove class presented a global disagreement (up to 10%) higher than the others, principally in types exchange with mangrove classes, hypersaline plains and others, being that the last two had the lowest Kappa indices per class in all the classifications. The mangrove class showed a global disagreement maximum of 5% and a Kappa index greater than 0.90 in all classifications. Based on the above considerations, we conclude that the mangrove genera approach, even with a greater n sample, did not produced significant differences to distinguish genera through polarimetric techniques, be them polarimetric responses or scatter techniques. Two advances can be identified in the study of mangroves using time-series Sentinel-1A: σ°VH/σ°VV polarization rate is related to canopy dynamics, and the use of trimester images, representing different seasons for the classification of mangrove forests. In addition, the potential of SAR images for mapping mangrove forests using time-series images from C and L bands through machine learning techniques is also recognized.