Navegando por Assunto "Zona costeira"

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Acesso aberto (Open Access)
Análise multitemporal da linha de costa e indicadores de erosão na praia da Ponta D’Areia, ilha do Maranhão: diagnóstico dos impactos de obras costeiras
(Universidade Federal do Pará, 2024-08-29) SANTOS, Alessandro Ferreira dos; LIMA, Leonardo Gonçalves de; http://lattes.cnpq.br/5984899472616752; RANIERI, Leilanhe Almeida; http://lattes.cnpq.br/3129401501809850; https://orcid.org/0000-0002-9870-4879
The coastal zone is defined as the geographical transition space between the ocean and the continent. In the state of Maranhão, it comprises five sectors, including the Maranhão Golfão. Ponta D’Areia beach is located northwest of the Maranhão Island, making up this sector where tides can reach up to 7.2 meters in height. The beach is approximately 2.5 km long, bounded by the Anil River and São Marcos Beach. In 2014, the construction of a coastal groin was completed at Ponta D’Areia beach, aimed at containing erosion and preventing sedimentation towards the Anil River. In this context, the research addressed the following questions: (a) How did the shoreline change over 27 years? (b) What are the erosional, depositional, and stable sectors from a morphodynamic perspective, considering the period before and after the construction of the coastal groin at the beach? It was believed that the rigid engineering structure was intended to stop the sedimentation at the mouth of the Anil river, which did not occur. As a result, it was necessary to extend the groin to an "L" shape to attempt to curb sedimentation, but this led to continued erosional activity at the northeastern end of the beach. Therefore, the objective of this research was to conduct a multitemporal analysis of the Ponta D’Areia shoreline from 1996 to 2022 and assess its current vulnerability to erosion. The methodology included: (1) on-site observational analysis to fill out pre-defined tables related to coastal erosion geoindicators and collection of surface beach sediments in November 2022 and April 2023, during the dry and rainy seasons, respectively; (2) beach topography survey and orthophoto acquisition through drone flights in April 2023; (3) multitemporal shoreline analysis from 1996 to 2022 using Landsat satellite images, ArcGIS software, and the Digital Shoreline Analysis System (DSAS) extension, as well as shoreline projections for 10 and 20 years into the future; (4) application of the Coastal Erosion Vulnerability Index (CEVI) in three coastal sectors, through the evaluation of natural and anthropogenic parameters; and (5) assessment of the impacts of coastal engineering works on Ponta D’Areia beach. Results showed variations in the shoreline from -64.63 meters (-3.46 m/year: erosion) to 32.15 meters (2.39 m/year: acretion) from 1996 to 2022, with a projected advance of 157.76 meters (4.94 m/year) and retreat of -123.26 meters (-3.68 m/year) by 2032, and a projected advance of 101.93 meters (1.48 m/year) and retreat of -141.35 meters (-1.63 m/year) by 2042. The morphodynamic state of the beach was identified as dissipative through topographic mapping with a drone, and moderate vulnerability to coastal erosion in Sector I, the marina sector, which had the lowest CEVI of 4. Sector II, the groin sector, had CEVI of 6.37 (moderate vulnerability), while Sector III, the Lighthouse sector, had a CEVI of 6.8, indicating high vulnerability to coastal erosion. It was possible to observe how meteo-oceanographic processes (waves, littoral drift, tidal currents, winds, and estuarine discharge) are influencing shoreline variation, as well as human interventions (coastal occupation and construction of rigid structures). Coastal accretion intensified at the beach after the anthropogenic intervention with the groin construction. It is concluded that the multitemporal analysis of the shoreline in the study area between 1996 and 2022 revealed significant variations influenced by natural and anthropogenic factors. Even with human interventions to alter the resulting sedimentation caused by meteo-oceanographic agents, these natural processes continue to intensely shape the region's coastal dynamics and are mainly responsible for variations in the shoreline.
Acesso aberto (Open Access)
Conflito e gestão ambiental na zona costeira amazônica: o caso da vila do Camará, reserva extrativista (RESEX) marinha mestre lucindo, Marapanim - Pará - Amazônia - Brasil
(Revistas Brasileiras Publicações de Periódicos e Editora Ltda., 2020-03) SANTOS, Márcia Cristina; LOPES, Luís Otávio do Canto; BASTOS, Rodolpho Zahluth; FENZL, Norbert; MERLIN, Lise Vieira da Costa Tupiassu; SOARES, Daniel Araújo Sombra
The present study identified the existing socio-environmental conflicts and the main problems of environmental management in Vila de Camará, in the Marine Ext activist Reserve (RESEX) “Mestre Lucindo”. In this perspective, the relevance of this work consists of analyzing a community within a recently established Amazon Conservation Unit (UC) situation, which shares a great natural resources wealth. Considering that RESEX is in the management initial stages, the reflection on the existence of such conflicts and the measures taken by the managing body, in the figure of ICMBio, as well as the proposal of strategies capable of reducing such conflicts, make this study still more important. The methodological steps carried out were: bibliographic / documentary review and field visits. The main socioenvironmental conflicts verified at the site were: extremely conflicting land distribution; environmental degradation at Lembe Beach and overfishing. When focusing on Lembe Beach, two conflicts stand out: the irregular construction of tents (bars and restaurants) and the disposal of their waste directly in the sea / mangrove.
Acesso aberto (Open Access)
Conflitos socioambientais, desafios e possibilidades da gestão compartilhada: o caso da Reserva Extrativista Marinha Mestre Lucindo, em Marapanim-PA
(Universidade Federal do Pará, 2020-10-20) SANTOS, Márcia Cristina; BASTOS, Rodolpho Zahluth; http://lattes.cnpq.br/0697476638482653; LOPES, Luis Otávio do Canto; http://lattes.cnpq.br/1013147545099173
This paper analyzes socio-environmental conflicts, limits and possibilities in the context of the shared management of the Marine Master Lucindo Extractive Reserve (RESEX), in the municipality of Marapanim. Among the general aspects of RESEX, one that deserves to be highlighted is its recent creation, a factor that allowed monitoring from the embryonic stages of management. RESEX does not yet have a Management Plan in place, which provides the opportunity to suggest intervention techniques, and reinforces the relevance of the research. This work presents an article that discusses RESEX's socioenvironmental conflicts. In this article, the main socioenvironmental conflicts verified were overfishing, degradation of mangroves, predatory extraction of crab, extraction of wood in mangrove and dry land areas, improper disposal of solid waste, fires, accumulation of solid waste in rivers and streams, and land conflicts. With that, the bases were created to deal with the second article, which deals with the limits of shared management considering the existing conflicts. At this stage, the analyzes were restricted to the Deliberative Council, since this is the main instrument of shared management. The result of the reflections in this article pointed out that the limitations of shared management in the RESEX are: inefficiency of the information system among the majority of councilors, low level of participation of the population, difficulty in mediation regarding the interests of the members of the Deliberative Council, weak communication between the RESEX communities and the implementation of the Integrated Management Center (NGI). From these results, it was possible to think of techniques to be suggested in order to better deal with these limits. The techniques aimed at increasing social participation, income generation opportunities, strengthening interrelationships and partnerships between Council institutions, training and awareness of all those involved, increasing the dissemination of information about RESEX, encouraging communication between communities, with an emphasis on those furthest from the city center, encouraging organization and proactivity, in addition to the search for continuous improvement.
Acesso aberto (Open Access)
A dinâmica dos manguezais no Nordeste do Brasil: uma abordagem a partir de dados de sensores remotos e SIG.
(Universidade Federal do Pará, 2015-11-27) PEREIRA, Edson Adjair de Souza.; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252; 3282736820907252
This study assesses the dynamics of mangroves in the northeastern Brazil in the last four decades from the classification of remote sensing images based on geographic objects (GEOBIA). This methodology combines spectral, temporal and spatial information of multi-temporal images to create consistent objects (mangrove areas) for a statistical analysis from classified images. The objective of this study was to evaluate the changes in mangrove forest cover in all states of the northeastern Brazil between 1975 and 2008, with regard to the increase or decrease mangrove areas in response to natural (erosion and accretion) and anthropogenic (Aquaculture / salinicultura) variations. In this study were processed and analyzed remote sensing images (RADAMBRASIL, ALOS PALSAR, TM Landsat and SRTM) from GEOBIA approach. During the studied period, there was a reduction of ~ 1,545 km2 mangrove forest area in 1975 to ~ 1480 km2 in 2008. This represents a net loss of ~ 65 km2, which is equivalent to a decrease of 13% in the mangrove forest area. Of the nine states studied, only Ceará and Pernambuco showed a gain in coverage of mangroves, while all others were reduced. Among the total mangrove forest area lost during the study period (~ 953 km2), the aquaculture/saliniculture ponds represent ~ 10%. Importantly, in the states of Rio Grande do Norte and Ceará the conversion of mangrove areas for aquaculture/saliniculture ponds already represent ~ 41% and 32% of the total area of mangrove lost, respectively. Therefore, it concludes that the methodology used to assess the dynamics of mangroves in northeastern Brazil from different sources of remote sensing data was extremely effective. New strategies for recovery and sustainable use of mangrove areas should be established in order to conserve this ecosystem for future generations.
Acesso aberto (Open Access)
Dinâmicas territoriais no município de Salinópolis/PA: unidades espaciais, ações públicas e a conservação ambiental
(Universidade Federal do Pará, 2021-01-27) SOUZA, Geisa Bethânia Nogueira de; ROCHA, Gilberto de Miranda; http://lattes.cnpq.br/2436176783315749
Coastal spaces focus special attention with regard to ecological, political and social discussions contemporary because they are areas increasingly densely populated, encompass essential ecological functions and have huge economic importance. The production of space on the Amazon coast points to a diversified reproduction movement, causing problems related to the natural, social and economic dynamics, what resonates in contradictions that are revealed in the fragility of the public actions in the coastal municipalities. The Municipality of Salinópolis concentrates a diversity of socio-spatial practices marked by the complexity of the activities established in its spatial reproduction process. This study focuses on the territorial dynamics in the municipality of Salinópolis from the forms of use throughout the space production process. Analyzes that the use today generates social and environmental inconsistencies, with significant loss of its natural and landscape resources, which reveals that coastal policies are often economistic, giving priority to certain activities such as tourism and the urbanization. Several public actions are taking place in the municipality to manage productive activities. These actions can cause conflicts due to the discrepancy of land use that does not show concordance with social dynamics and environmental conservation.
Acesso aberto (Open Access)
Geoindicadores de vulnerabilidade à erosão em praias estuarinas, costa amazônica, Pará.
(Universidade Federal do Pará, 2022-04-19) NOVAES, Gabriela de Oliveira; RANIERI, Leilanhe Almeida; http://lattes.cnpq.br/3129401501809850; https://orcid.org/0000-0002-9870-4879
The coastal zone (CZ) is a region responsible for various ecological functions, and also object of concern due to its uses and anthropic pressures, which affect its balance and environmental integrity. The beach is one of the most important environments in CZ, due to its intense use by the human population, having ecological function for many organisms and being a natural protection against physical forcers (waves, tides and chains). The anthropogenic occupation on a particular beach can aggravate coastal erosion (natural process of the morphological amendment of the environment, due to the interaction with physical agents). This occurs on the island of Mosqueiro, object of study of this work, where erosive processes have been intensified in recent decades, combined with urbanization. Observing this problem, the present research aims to analyze vulnerability to erosion on the Amazonian estuarine beaches of the Mosqueiro Island, well as evaluating the degree of coastal risk to which they are exposed. Using geoindicators, index and classification of local vulnerability were obtained. Being the index composed of coastal variables: morphology and granulometry of the beach, sedimentary swing, variation of the coast line, cliffs, natural barriers; and continental variables: land elevation, vegetation, coastal engineering structures, percentage of occupation and soil permeability. Then it was carried out: (a) collection of topographic data and sealing samples on 16 beaches; (b) observational analysis with Checklist of geoindicators of coastal erosion in loco and through satellite images; c) treatment of data collected in the field and by remote sensing; d) Use of the coastal vulnerability index to evaluate erosion on the beaches; and, e) identification of risk degree in these beaches. The results demonstrate that 8 of the 16 analyzed beaches are classified with high vulnerability (IVC: 5,0-7,4) and accentuated coastal risk, and that the presence of active cliffs, wall of arrimation and high occupation next the beaches stood out as favoring ones for this result. The data indicated high human occupation (> 70% on most beaches), since several forms of land use are frequent on the island, whether for homes or establishments (shops, restaurants, inns), which raises local risk for the occurrence of damage caused by erosion. In general, the adapted method of this study for Amazonian estuarine beaches, proved to be an interesting tool to be used in urban planning and to minimize future impacts of coastal erosion. It provides information that can aid in decision-making focused on coastal management and choosing which mitigatory measures can be carried out. Thus, the importance of this analysis and continuous coastal monitoring is reinforced through the use of geoindicators.