Impactos no sistema de dunas: dinâmica natural versus interferência antrópica

The shoreline of Capão da Canoa, RS, alternates densely populated areas with non urban empty spaces that still have their natural features preserved. This paperwork aimed to evaluate the foredunes vulnerability, by field evaluation along the shoreline in wintertime and summertime, using a field checklist. After rating some parameters, a Vulnerability Index was established for each profile. The highest values matched the most densely populated areas in that municipality, due to the position of the urban area that often shortens the width of the foredune ridges. The superiority of the wintertime vulnerability index when compared to summertime, changes the consensus about the human interference as the main vector of vulnerability. The major factors contributing to foredune degradation were: beach condition during winter time and use pressure, during summertime, indicating the high vulnerability associated with some profiles along the shoreline.A orla de Capão da Canoa, RS, intercala áreas de alta densidade ocupacional com áreas não urbanizadas que preservam suas características naturais. Neste trabalho, buscou-se analisar o índice de vulnerabilidade das dunas frontais, a partir de levantamentos de campo realizados no inverno e verão, utilizando-se uma lista de parâmetros. A partir da taxação destes, atribuiu-se um índice de vulnerabilidade para cada perfil. Os valores mais altos coincidiram com as áreas mais urbanizadas do município, devido à posição da urbanização que reduz a largura dos cordões de dunas frontais. A superioridade dos valores do índice de vulnerabilidade de inverno ao de verão altera o consenso sobre a interferência humana como principal vetor de vulnerabilidade. Os fatores que mais contribuíram para a degradação das dunas frontais foram: a condição de praia, no inverno, e a pressão de uso, no verão, indicando a alta fragilidade de alguns perfis ao longo da orla

Degradation of a transgressive coastal Dunefield by pines plantation and strategies for recuperation (Lagoa Do Peixe National Park, Southern Brazil)

The transgressive dunefield of the Lagoa de Peixe Natural Park was modified drastically due to intensive pine plantation and the leeward development of the associated degraded areas. The present study analyzed the disturbances in the dunefield of the Lagoa do Peixe Natural Park due to pine tree plantation and the impact of the subsequent deforestation program conducted in the region. Aerial photographs, satellite images, and DGPS topographic data collected over a 70-year-long period were retrieved, analyzed, and compared, which allowed the observation of the geomorphological evolution of the dunefield. In addition, a profile of GPR on the inlet (during a period with the channel closed) was analyzed. In 1948, the surface of the sand barrier was occupied by high transverse dunes and low barchan dunes. Pine tree plantation on the inner side fixed the transgressive dunes and, consequently, avoided the filling of the shallow lagoon, although degraded areas were generated on the lee side of the pines. Simultaneous pine plantations in the backshore avoided the aeolian sediment input to the dunefield, generating a large interdune area along with the development of a few parabolic dunes, which resulted in cannibalization of the transgressive dunes. In 2001, pine trees occupied 15.03% of the total area analyzed in the present study, while the degraded area accounted for 10.81% of the total area. Progressive deforestation was performed (ring bound technique for tree gradual death), maintaining three lines of pines in contact with the dunes, to promote autochthonous vegetation growth, thereby preventing the filling of the adjacent lagoon with aeolian sediments. By the year 2018, the pine tree plantation area reduced to 3.25%, the dunefield area was 79.03%, and the extension of the degraded areas had increased and reached 17.71% of the total area. The pine tree plantation and the deforestation for conservation purposes are the main factors explaining the degradation of the dunefield during the period between 1948 and 2018, while regional climatic oscillations contributed as the secondary factor. Although internationally controversial, the present case study demonstrates that the removal of this exotic vegetation, through dune vegetation recovery programs, is often unsuccessful and may generate more degraded areas. However, in the case presented here, it was essential to remove the forest to ensure the dune field geodynamics and, therefore, the base (biotope) of the natural system (maintenance of the lagoon and the dunefield)

Beach litter distribution in Admiralty Bay, King George Island, Antarctica

In the Antarctic Peninsula, most important activities are touristic visits, from the second half of the 20th Century, and scientific investigation linked to 75 research stations. Beach litter content/abundance was investigated at 17 beaches in Admiralty Bay (King George Island, Antarctica) and the type of plastic material was determined by Raman spectroscopy. An average value of 0.16 items m−1 was observed. Wood items consisted of processed wood fragments representing 47.27% of the total. Foam represented 21%, hard plastic pieces 9.68% (consisting of polyvinyl chloride or high density polyethylene), metal 3.37%, rubber fragments 2.81%, foamed plastic pieces 2.66% (composed by polystyrene), the rest of categories representing less than 2% of the total. Wood debris and metal are essentially remnant objects of ancient whaling activities and research expeditions, polyurethane and expanded polystyrene materials have different origins and hard plastic, rubber, paper/cardboard and paint fragments seem mostly linked to present research activities

Mangrove Forests Evolution and Threats in the Caribbean Sea of Colombia

Colombia has approximately 379,954 hectares of mangrove forests distributed along the Pacific Ocean and the Caribbean Sea coasts. Such forests are experiencing the highest annual rate of loss recorded in South America and, in the last three decades, approximately 40,000 hectares have been greatly affected by natural and, especially, human impacts. This study determined, by the use of Landsat multispectral satellite images, the evolution of three mangrove forests located in the Colombian Caribbean Sea: Malloquin, Totumo, and La Virgen swamps. Mangrove forest at Mallorquin Swamp recorded a loss of 15 ha in the period of 1985-2018, associated with alterations in forest hydrology, illegal logging, urban growth, and coastal erosion. Totumo Swamp lost 301 ha in the period 1985-2018 associated with changes in hydrological conditions, illegal logging, and increased agricultural and livestock uses. La Virgen Swamp presented a loss of 31 ha in the period of 2013-2018 that was linked to the construction of a roadway, alterations of hydrological conditions, illegal logging, and soil urbanization, mainly for tourist purposes. Although Colombian legislation has made efforts to protect mangrove ecosystems, human activities are the main cause of mangrove degradation, and thus it is mandatory for the local population to understand the value of the ecosystem services provided by mangroves

Marine litter arrived: Distribution and potential sources on an unpopulated atoll in the Seaflower Biosphere Reserve, Caribbean Sea

The Albuquerque atoll was studied as a representative natural laboratory to explore the role of sea-based sources of marine litter. This work aimed to identify the small-scale spatial distribution of marine litter (i.e., plastic, glass, paper, and others) as well as to explore the connectivity among the atoll habitats (sand beach, water surface, and reef) to give insights of potential sources of marine litter (>5 cm), mainly plastics. Marine litter was dominated by plastic items, as expected, with an average value of 0.5 items/m2. Large microplastics (1–5 mm) were also sampled on beaches with an average value of 90 particles/m2. In the atoll inner lagoon, marine litter was also composed by plastic, mainly fragments (average 0.059 items/m3). The predominance of plastic fragments on both the sea surface and beaches of the atoll makes inferences on sources limited. However, o fishing activities and sea-based sources might be relevant since local sources are very limited

Coastal dune management : the use of geographic information system (GIS) in the development of management plans in the coast of Rio Grande do Sul, Brazil

Constituídas por grandes acumulações de areia, as dunas frontais são feições naturais da maioria das praias arenosas. As áreas de dunas são consideradas Áreas de Proteção Permanente (APPs) no Brasil, e, para a conservação desses ambientes, faz-se necessário o estabelecimento de planos, programas e medidas governamentais orientados a disciplinar os seus usos e/ou manejos. O desenvolvimento de projetos para a gestão do sistema de dunas deve incluir um diagnóstico do ambiente (características naturais e o grau de intervenção humana), a tendência das mudanças e as ações para manutenção ou recuperação do sistema. O objetivo deste trabalho é demonstrar a potencialidade do uso de um Sistema de Informações Geográficas (SIG) para o diagnóstico ambiental de dunas, bem como salientar a importância da integração de dados regionais em ambiente SIG, a fim de se obter melhores resultados para subsidiar a tomada de decisão na elaboração de planos de gestão para o Gerenciamento Costeiro Integrado, por meio de estudos de caso de duas cidades no litoral do estado do Rio Grande do Sul, sul do Brasil (municípios de Capão da Canoa e Arroio do Sal). O uso de um SIG permite atualizações em várias escalas de tempo e também a análise conjunta de múltiplos dados de diferentes fontes. Essas características auxiliam os trabalhos na região costeira, ambiente com uma grande dinâmica de formas e processos. Para a caracterização, o diagnóstico e o planejamento das áreas de estudo, dados primários e secundários das duas áreas foram coletados e integrados em ambiente SIG, e, assim, pôde-se dividir os ambientes em diferentes setores, possibilitando o planejamento das intervenções necessárias em cada um deles. A espacialização das intervenções sugeridas permitiu sua visualização em mapas, sendo esta informação inserida como um novo plano de informação no projeto em SIG. Algumas das intervenções sugeridas em alguns locais visando à manutenção/recuperação do sistema de dunas incluem: passagem de tubulações abaixo da crista da duna (para a passagem condicionada de cursos d’água), construção de passarelas onde a passagem de pedestres é intensa (para ordenar o acesso à praia), remoção de vegetação exótica etc. Os resultados obtidos demonstram a possibilidade do uso de um SIG nos estudos de gestão costeira, gerando bons resultados no diagnóstico e planejamento das duas áreas de estudo. Como produto final dos planos de manejo desenvolvidos, todos os dados coletados e gerados são disponibilizados em arquivos no formato SIG, bem como em formato de planilha, junto com o relatório descritivo. No âmbito municipal, as vantagens encontram-se na facilidade de armazenamento e disponibilização dos dados, além de proporcionar a fácil modificação destes e também o acompanhamento da evolução dos projetos. A utilização de SIG também pode promover e facilitar a troca de informações entre as instituições e, a longo prazo, pode permitir a integração de todas as informações em um único banco de dados, podendo auxiliar na tomada de decisão dos órgãos municipais, estadual e federal.Foredunes are geomorphological features present in most of the sand beaches around the world. Under the Brazilian law, dunes are considered Permanent Protection Areas and, for conservation of these environments, it is necessary the establishment of plans, programs and measures by the government to discipline their use and management requirements. The development of projects for dune system management should include an environmental diagnosis (natural characteristics and human intervention degree), the trend of changes and the actions for maintenance or recovery of the system. The aim of this work is to evidence the potential of using a Geographic Information System (GIS) for the environmental diagnosis of dunes, as well as stress the importance of regional data integration within a GIS, for the purpose of obtaining better results to support decision making in the development of management plans for integrated coastal zone management. Study cases of two coastal cities in the State of Rio Grande do Sul, southern Brazil (Capão da Canoa and Arroio do Sal cities), are shown. The use of GIS allows updates at several time scales and also the joint analysis of multiple data from different sources. These characteristics assist work in coastal zones, an environment with highly dynamic forms and processes. For the characterization, diagnosis and planning of the two study areas, primary and secondary data were collected. Secondary data consists of bibliographic and cartographic search, and remote sensing data. Primary data consists of field observations, control points collected with GPS, photographic records (beach access, watercourses, irregular occupation, beach uses, dune uses, etc.), topographic data and vegetation identification. After collection, data were inserted in data layers and integrated in the GIS project. Using geoprocessing tools it was possible to calculate areas, measure foredune width and delimit the boundaries of Permanent Protection areas (using distance criteria), leading to further information to be obtained/added in the GIS. Distance criteria for delimitation of Permanent Protection areas were based in the law of the state environmental agency (FEPAM). For the city of Capão da Canoa, increases in sea level caused by storm surge were modelled in the GIS, in order to identify foredune areas susceptible to degradation. Results showed that water courses that cross the dune system are the preferential erosion zones in storm surge events. An evaluation based in the mapped elements and field observations, allowed the assignment of a coastal vulnerability index to each 500 meters beach segment. The higher the vulnerability index, the greater the fragility of the dune system. The areas with the highest index are the ones in which greater efforts are required (interventions/management). In the studied areas, these indexes allowed the planning of interventions required for each beach sector. Both cities have an extensive shoreline and dune areas affected by erosion (caused by storm surge effects, displacement of watercourses, planting of exotic vegetation and lack of planning for the shoreline – with disordered use of this natural system). A well developed urban area is present in Capão da Canoa city, where a discontinuous and highly segmented dune area exists. Preserved sections occur mostly in the non-urban areas. In Arroio do Sal city, there is an extensive and well preserved shoreline and dune system. The major problems affecting dune system in this city are erosion by storm surge and planting of exotic vegetation. With the environmental diagnosis and the vulnerability index for each beach sector, management proposals in different sectors of the shoreline were performed, and spatialization of the suggested actions/interventions was implemented in the GIS. This spatialization allowed visualization of all the beach sectors in maps, and this information was also added to the GIS project as new data layers. For dune system integrity maintenance/recovery in some sectors, some of the suggested interventions include pipe passing under the frontal dune crest (for controlled passage of watercourses), construction of walkways where the crosswalk is very intense (ordering the access to the beach), removal of exotic vegetation, etc. The results demonstrate the possibility of using GIS in coastal management studies, showing good results in the diagnosis and planning of the two study areas. As a final product of the management plans developed, all the collected and generated data are provided in GIS file format and in spreadsheets in a PDF report. At the municipal level, the advantages are ease of storage and availability of data, facilitating data modification in case of scenario alteration for the shoreline. The use of a GIS can also promote and facilitate the exchange of information between institutions and, in the long term, can allow the integration of all information into a single database to assist in decision making at the municipal, state and federal agencies. Keywords: coastal management, geospatial technology, database, coastal modelling

Stratigraphic stacking patterns and their reflections on the holocene coastal barrier morphology of the middle coast of Rio Grande do Sul, Brazil

Neste trabalho, investigou-se com detalhe a barreira holocênica do litoral médio do Rio Grande do Sul (RS), entre as localidades do Estreito e de Bacupari. Este trecho do litoral corresponde a mais expressiva projeção costeira de larga-escala da costa do RS. Dados geofísicos (Georadar) e geomorfológicos superfi ciais permitiram importantes descobertas. Na porção sul da projeção costeira, entre o Estreito e o setor norte da Lagoa do Peixe, a barreira holocênica exibe um comportamento evolutivo dominantemente retrogradacional (provavelmente desde 6 ka até o presente), o qual foi determinado por um longo período de balanço negativo de sedimentos. Já na porção norte da projeção, entre o Balneário Mostardense e Bacupari, a barreira mostra uma inversão de comportamento retrogradacional para progradacional. Tal mudança evolutiva, expressa numa progradação que varia de 230 a 1800 m, é possivelmente oriunda de uma alteração no balanço de sedimentos (balanço negativo para positivo) que pode ter ocorrido somente há alguns séculos, ou mesmo poucos milênios. A mudança para um padrão de empilhamento progradacional mostrou-se crescente em dimensão (extensão do registro progradacional) do meio para o norte da projeção costeira. É possível sugerir que essas tendências evolutivas em escala geológica (10²-10³ anos) vão continuar no decorrer das próximas décadas. Informações acerca do comportamento evolutivo da linha de costa nos últimos séculos e milênios podem servir como subsídios do meio físico na gestão costeira do litoral médio do RS.In this work, the Holocene barrier of the middle coast of Rio Grande do Sul (RS), located between Estreito and Bacupari, was investigated in detail. This stretch of the coast corresponds to the most expressive large-scale coastal projection of the RS coast. Important discoveries were made through subsurface geophysical (GPR) and surfi cial geomorphology data. In the southern portion of the projection, between Estreito and the northern sector of Lagoa do Peixe, the Holocene barrier exhibits a predominantly retrogradational evolutionary behavior (probably from 6 ka and the present), which was determined by a negative sediment budget in the long term. On the other hand, in the northern portion of the projection, between Balneário Mostardense and Bacupari, the barrier shows a reversal from retrogradational to progradational behavior. Such evolutionary change, expressed in a progradation ranging from 230 to 1800 m, is possibly attributed to a change in the sediment budget (negative to positive budget) that may have occurred only a few centuries ago, or even a few millennia. The reversal towards a progradational stacking pattern showed an increase in size (length of the progradational record) from the middle to the north of the coastal projection. It is possible to suggest that these evolutionary trends on a geological scale (10²-10³ years) will continue over the next decades. Information about the coastline evolutionary trends in the last centuries and millennia can be useful as subsidies for the coastal management of the middle coast of RS

Optically stimulated luminescence (OSL) dating of a sand ridge plain in the northern littoral of rio grande do sul, Brazil

Neste trabalho, é utilizada a aplicação da LuminescênciaOpticamente Estimulada (LOE) para datar sedimentos em uma planície de cordões litorâneos arenosos de margem lagunar, na porção norte do litoral do Rio Grande do Sul (RS). Essa planície de cordões constitui parte da margem nordeste da Lagoa dos Quadros, segunda maior lagoa do sistema lagunar norte do RS. Um total de cinco amostras foram coletadas em diferentes cordões da planície, na porção de máxima progradação (região central da planície). Neste estudo, as idades de luminescência foram obtidas por doses equivalentes estimadas por protocolo SAR (Single-Aliquot Regenerative dose) aplicado a alíquotas de grãos de quartzo. Concentrações de K, U e Thpara cálculo de taxas de dose foram medidas por espectrometria gama de alta resolução. As amostras estudadas apresentaram doses equivalentes entre 1,8 e 3,6 Gy e taxas de dose entre 0,442 e 0,806 Gy/ka. As idades obtidas variaram entre 2,6 ± 0,2a 6,3 ± 0,4 ka. Foram definidos cinco intervalos com diferentes taxas de progradação na planície de cordões. Esses intervalos podem ser enquadrados em dois estágios: o primeiro marcado por um aumento na taxa de progradação média, e o segundo, com o decréscimo nas taxas. O primeiro estágio é caracterizado por uma grande disponibilidade de sedimentos que foram transportados para o interior da Lagoa dos Quadros, durante as fases de desenvolvimento dos depósitos eólicos da barreira holocênica, que se desenvolveu ao mesmo tempo, entre a lagoa e o Oceano Atlântico. O segundo estágio, com taxas que se situam num patamar de cerca de metade do primeiro estágio, provavelmente se desenvolveu em uma época mais úmida e, consequentemente, em um período com menor transporte de areias eólicas para o interior da lagoa; e também em um tempo em que os processos costeiros ativos da barreira oceânica holocênica já se encontravam muito distantes da Lagoa dos QuadrosThe application of Optically Stimulated Luminescence (OSL) dating to constrain the age of lagoonal sand ridges in the northern littoral of Rio Grande do Sul (RS), is tested in this work. These sand ridges make up part of the northeast margin of the Quadros Lagoon, the second largest lagoon of the north littoral of RS. Five samples from five ridges of the maximum progradational zone (central portion) were dated. In this work, luminescence ages were obtained through equivalent doses measured in quartz aliquots using the Single-Aliquot Regenerative dose (SAR) protocol. The concentrations of K, U and Th for dose rates calculation were measured with high-resolution gamma ray spectrometry. The studied samples show equivalent doses between 1.8 and 3.6 Gy and dose rates between 0.442 and 0.806 Gy/ka. The ages range from 2475 to 6745 years. It was possible to estimate the average rate of progradation of the studied plain. Five intervals were established with different progradation rates. These intervals were grouped in two stages with higher (growing) and a lower average rates of progradation. The first stage was characterized by a higher rate of sediment supply. This is probably due to a connection with the evolution of the initial aeolian deposits of the Holocene oceanic barrier, that started to develop approximately 1100 years before the studied sand ridge plain, between the lagoon and the Atlantic Ocean. The second stage, with lower rates, are probably related to a more humid period that has conditioned a lower aeolian transport into the lagoon, and also due to an increase of the distance between the active coastal processes of the oceanic barrier and the Lagoa dos Quadros

Geomorphology and stacking patterns of the Holocene barrier in the northern Rio Grande do Sul coast

Título en inglés: Geomorphology and stacking patterns of the Holocene barrier in the northern Rio Grande do Sul coastPalabras clave en portugués e inglésResumen en portugués e inglésBarreiras costeiras podem exibir uma variedade de características estratigráficas e morfologias, refletindo os fatores condicionantes da sua formação e desenvolvimento atuantes em diferentes escalas temporais (secular e milenar) e espaciais, determinando padrões de empilhamento estratigráfico distintos. Neste trabalho, investiga-se a barreira holocênica no litoral norte do Rio Grande do Sul, entre o balneário de Dunas Altas e a praia de Xangri-Lá, com o objetivo de analisar em detalhe a extensão e as características dos setores que apresentam padrões de empilhamentos estratigráficos progradacionais e retrogradacionais. Assim, perfis de Georadar (GPR) foram adquiridos perpendicularmente à linha de costa, ao longo de 65 km. Uma sondagem SPT (Standard Penetration Test) foi realizada até 20,45 m de profundidade e a análise morfológica da barreira holocênica foi conduzida através de modelo digital de superfície (TanDEM-X). Definiram-se intercalações longitudinais no padrão de empilhamento estratigráfico da barreira. Dunas Altas apresenta um padrão de empilhamento estratigráfico progradacional. Em Quintão, 6,5 km ao norte, a barreira muda seu padrão de empilhamento estratigráfico para retrogradacional. Esse padrão se mantém até Tramandaí Sul, onde se altera para progradacional em um intervalo de 1 km, mantendo-se assim até Xangri-Lá. A delimitação dos padrões de empilhamento estratigráfico distintos possibilitou o entendimento do comportamento da barreira em uma escala de longo período, representando também uma importante contribuição à gestão costeira, principalmente no que diz respeito à delimitação de setores com comportamento erosivoCoastal barriers can exhibit an array of stratigraphies and morphologies reflecting the drivers acting during their evolution in different temporal (secular and millennial) and spatial scales, leading to distinct stacking patterns. In this work, the Holocene coastal barrier in the northern coast of Rio Grande do Sul is investigated between Dunas Altas and Xangri-Lá aiming a detailed analysis of the extension and characteristics of progradational and retrogradational sectors. In order to do so, GPR sections were collected along 65 km of the barrier. A drillhole (20,45 m depth) was acquired and a morphological analysis was conducted through digital surface model (TanDEM-X). An alternation in the barrier stacking patterns was defined. Dunas Altas shows a progradational pattern. At Quintão, 6,5 km northwards, the barrier changes to a retrogradational pattern, which is maintained until South Tramandaí, where it changes quickly to a progradational pattern in a 1 km stretch of coast, keeping this stacking pattern until Xangri-Lá. The delimitation of distinct stacking patterns contributes to the understanding of the long-term barrier behavior and supports coastal management mainly regarding the delimitation of erosive sectorsEsta pesquisa foi viabilizada por meio de bolsa de mestrado concedida à Débora Sayuri Zanchi Watanabe pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico -CNPq (133093/2017-4

Geomorphology and stacking patterns of the holocene barrier in the northern Rio Grande do Sul coast

Barreiras costeiras podem exibir uma variedade de características estratigráficas e morfologias, refletindo os fatores condicionantes da sua formação e desenvolvimento atuantes em diferentes escalas temporais (secular e milenar) e espaciais, determinando padrões de empilhamento estratigráfico distintos. Neste trabalho, investiga-se a barreira holocênica no litoral norte do Rio Grande do Sul, entre o balneário de Dunas Altas e a praia de Xangri-Lá, com o objetivo de analisar em detalhe a extensão e as características dos setores que apresentam padrões de empilhamentos estratigráficos progradacionais e retrogradacionais. Assim, perfis de Georadar (GPR) foram adquiridos perpendicularmente à linha de costa, ao longo de 65 km. Uma sondagem SPT (Standard Penetration Test) foi realizada até 20,45 m de profundidade e a análise morfológica da barreira holocênica foi conduzida através de modelo digital de superfície (TanDEM-X). Definiram-se intercalações longitudinais no padrão de empilhamento estratigráfico da barreira. Dunas Altas apresenta um padrão de empilhamento estratigráfico progradacional. Em Quintão, 6,5 km ao norte, a barreira muda seu padrão de empilhamento estratigráfico para retrogradacional. Esse padrão se mantém até Tramandaí Sul, onde se altera para progradacional em um intervalo de 1 km, mantendo-se assim até Xangri-Lá. A delimitação dos padrões de empilhamento estratigráfico distintos possibilitou o entendimento do comportamento da barreira em uma escala de longo período, representando também uma importante contribuição à gestão costeira, principalmente no que diz respeito à delimitação de setores com comportamento erosivo.Coastal barriers can exhibit an array of stratigraphies and morphologies reflecting the drivers acting during their evolution in different temporal (secular and millennial) and spatial scales, leading to distinct stacking patterns. In this work, the Holocene coastal barrier in the northern coast of Rio Grande do Sul is investigated between Dunas Altas and Xangri-Lá aiming a detailed analysis of the extension and characteristics of progradational and retrogradational sectors. In order to do so, GPR sections were collected along 65 km of the barrier. A drillhole (20,45 m depth) was acquired and a morphological analysis was conducted through digital surface model (TanDEM-X). An alternation in the barrier stacking patterns was defined. Dunas Altas shows a progradational pattern. At Quintão, 6,5 km northwards, the barrier changes to a retrogradational pattern, which is maintained until South Tramandaí, where it changes quickly to a progradational pattern in a 1 km stretch of coast, keeping this stacking pattern until Xangri-Lá. The delimitation of distinct stacking patterns contributes to the understanding of the long-term barrier behavior and supports coastal management mainly regarding the delimitation of erosive sectors