Impactos de um ambiente em mudança nos recifes de corais marginais do Oceano Atlântico Tropical

Novo artigo publicado na revista Ocean and Coastal Management pelo GT1.2 (Recifes e Ecossistemas Coralinos), intitulado “Impacts of a changing environment on marginal coral reefs in the Tropical Southwestern Atlantic”, de autoria de Marcelo Oliveira Soares, Sergio Rossi, Anne Rebouças Gurgel, Caroline Costa Lucas, Tallita Cruz Lopes Tavares, Beatriz Diniz, Caroline Vieira Feitosa, Emanuelle Fontenele Rabelo, Pedro Henrique Cipresso Pereira, Ruy Kenji Papa de Kikuchi, Zelinda M.A.N. Leão, Igor Cristino Silva Cruz, Pedro Bastos de Macedo Carneiro, Lorenzo Alvarez-Filip, discute os efeitos de múltiplas pressões sobre os recifes brasileiros.

Uma ampla avaliação revela que eventos de branqueamento afetaram 26 espécies nos últimos 26 anos (1994–2020). Entre 1994 e 2018 nenhuma espécie sofreu mortalidade em massa após o branqueamento. No entanto, as ondas de calor recentes e intensas de 2019 e 2020 causaram altas taxas de mortalidade em vários corais mostrando que esses recifes não são protegidos a longo prazo e nem refúgios universais. Essas mudanças e outros fatores como pesca🪝, urbanização, mineração, derramamentos de óleo, aumento da sedimentação, ondas de calor, lixo marinho, contaminação urbana, efluentes agrícolas e industriais e espécies invasoras são as pressões mais severas.

O artigo também discute a “hipótese de refúgio do recife brasileiro” a qual poderia ser parcialmente aplicada para alguns corais resistentes ao estresse durante distúrbios agudos (refúgio de curto prazo). No entanto, tal fato não garante que os recifes brasileiros devem ser assumidos como um ecossistema que servirá de refúgio contra as mudanças climáticas.

Por fim, os autores argumentam que é essencial a adoção de estratégias de gestão a nível local e global.

Acesse e compartilhe o artigo completo pelo link: https://authors.elsevier.com/a/1d9-K3RKK-qP4f

RESUMO

The peculiar shallow-water reefs of the Tropical Southwestern Atlantic Ocean have thrived in conditions considered suboptimal (e.g., moderate turbidity, higher level of nutrients, and resuspension of sediments) under the optics of classical coral reefs. Recently, these marginal reefs have been hypothesized to provide climate-change refugia from natural and anthropogenic impacts; yet with little empirical evidence. Therefore, in this article we discuss the known effects of multiple pressures on the Brazilian reefs. A wide evaluation of the peer reviewed literature reported that bleaching events affected 26 species of scleractinians, hydrocorals, octocorals, and zoanthids in turbidzone reefs over the last 26 years (1994–2020) in the Tropical SW Atlantic Brazil. Between 1994 and 2018 no species suffered post-bleaching mass mortality. However, the recent and intense heatwaves of 2019 and 2020 caused higher mortality rates in several key foundation corals (e.g., Millepora alcicornis, Millepora braziliensis, and Mussismilia harttii) showing that the SW Atlantic reefs are not long-term protected and universal refuges. Moreover, other direct and indirect human pressures threaten these tropical reefs. Local and regional (e.g., pollution and fisheries) and large-scale pressures (e.g., global warming and marine heatwaves) act simultaneously on the health of these reefs, which intensifies negative species-specific impacts. We outline the occurrence of pressures that have been important factors responsible for the reduction in species richness and reef fish biomass, changing geoecological functions, altered reef composition and dominant morpho-functional groups, as well as phase shifts. Along with large-scale climatic changes, such as heatwaves, fisheries, urbanization, mining disasters, oil spills, increased sedimentation, increased warming, marine debris, contamination by domestic, agricultural, and industrial effluents, and introduction of invasive species are likely the most severe pressures on Brazilian reefs. We discuss that the “Brazilian reef refuge hypothesis” could be partially applied for some stress-tolerant massive corals during acute disturbances (short-term refuge); yet should not be assumed as a reef ecosystem-wide feature under ongoing environmental change. Therefore, we argue that it is essential to alleviate the main local and regional human impacts and to adopt resilient-based management strategies at local and global scales to protect the lowfunctional redundancy and higher endemism of these unique marginal coral reefs.

TAOS (Tropical Atlantic Observing System)

Foi publicado em maio de 2021 o relatório completo do TAOS (Tropical Atlantic Observing System) que teve entre seus autores principais o prof. Moacyr Araujo, coordenador do do GT3.0 (Variabilidade climática, ciclos biogeoquímicos e fluxo de CO2 no oceano Atlântico tropical) do inctAmbtropic. O relatório resume os resultados de duas oficinas realizadas e discussões subsequentes do comitê revisor, incluindo contribuições de outros membros da comunidade de pesquisadores que atuam no Atlântico Tropical (você pode fazer o “download”do relatório ao final desta postagem).

Abaixo alguns trechos do Resumo Executivo:

“The tropical Atlantic is the smallest of Earth’s tropical ocean basins, one half the width, west to east, of the tropical Indian Ocean and less than one fifth that of the tropical Pacific. Thus, the tropical Atlantic interacts intimately with its bordering lands, strongly influencing their weather and climates, and it is readily accessible by the region’s inhabitants. At the same time, the tropical Atlantic plays an outsized role in the global climate system. Through the Atlantic Meridional Overturning Circulation (AMOC), it delivers nearly half a petawatt of energy from the Southern to the Northern Hemisphere, and it has marked, if still not fully understood, impacts on globally significant variations in the tropical Indian and Pacific Oceans”

“All countries bordering the tropical Atlantic experience important societal challenges driven by regional ocean processes and air-sea-land interactions. These are exacerbated by climate change, which induces new emerging threats. Examples include floods and droughts in South America and West Africa, more intense storms and hurricanes, and continuing sea-level rise that increases flooding risks and episodes of coastal erosion. Other regional emerging extreme events such as ocean heat-waves and episodes of anoxia and acidification amplify the vulnerabilities of regional marine ecosystems – systems already stressed by overfishing and pollution. Moreover, recent studies show that the tropical Atlantic has two-way connections with the Pacific and appears to play a driver role in mid- and high-latitude climatic events including the occurrence of impactful mid-latitude extremes throughout the year)”.

“The present TAOS review comes at an inflexion point for the tropical Atlantic, where scientific progress, demands on its resources, and environmental changes resulting from local and global stressors simultaneously are accelerating. At this juncture, there are great rewards to be reaped from an enhanced and invigorated TAOS, rationally planned and responsibly governed and coordinated. This report offers the rationale and the strategy for achieving a TAOS that will be well suited to serve the societal and scientific needs of the Atlantic basin and the globe over the coming decades. The recommended enhancements to the observing system across the range of platforms, with their associated sampling timescales, variables measured, and ranges of depths is expected lead to improved forecasts and projections of phenomena ranging from daily weather, fisheries and coastal managements, to anthropogenic climate change over multiple decades”.

Mudanças Climáticas e a Evolução Holocênica do Delta do rio São Francisco

Um trabalho recentemente publicado na revista Marine Geology (IF: 3.04) pelo GT1.1 (Deltas e Erosão da Linha de Costa) intitulado “Effects of Holocene climate changes and anthropogenic river regulation in the development of a wave-dominated delta: The São Francisco River (eastern Brazil)” de autoria de José Maria Landim Dominguez e Junia Kacenelenbogen Guimarães, discute os efeitos das mudanças climáticas durante o Holoceno e da regulação antropogênica do rio São Francisco no desenvolvimento do seu delta e conclui que a construção do delta ocorreu em pulsos associados a períodos mais úmidos na bacia hidrográfica. O artigo também discute as causas da erosão severa que afeta a desembocadura fluvial nas última décadas.

Modelo evolutivo do delta do São Francisco, durante o Holoceno

Erosão da linha de costa durante o periodo 1960-2020 no delta do São FranciscoABSTRACT

The São Francisco River is the fourth longest river in South America and one of the most regulated. Severe coastalerosion has affected the delta shoreline since 1985, leading to the complete destruction of Cabeço village be- tween 1997 and 1999. In this study, we mapped and radiocarbon dated the beach ridge sets occurring on the delta plain and performed a detailed analysis of the delta shoreline changes since 1960. During the Holocene, the delta plain construction was punctuated and took place during episodes of higher river discharges coincident with Bond events 4, 2 and 1 and periods of higher precipitation in the river basin, as reconstructed by δ18O measurements in cave speleothems. The last major episode of delta construction apparently ended at approxi- mately 1.0 ka cal. BP. Since that time, riverine sediment input has been just sufficient to maintain the shoreline. A comparison of historical maps and aerial photographs showed that from 1853 to 1960, the shoreline at the river mouth remained in approximately the same position. A decrease in rainfall in combination with river regulation, particularly after 1985, triggered extensive erosion at the delta shoreline. This erosion was not caused by sediment retention behind the major dams but instead resulted from changes in the backwater/drawdown effects deriving from river regulation. Shoreline erosion mostly affected the river mouth. The mobilized sediments caused progradation of the downdrift shoreline. Updrift of the river mouth, the shoreline remained stable, as it had already reached an equilibrium orientation in which the net longshore transport was zero

O trabalho completo pode ser acessado em: https://doi.org/10.1016/j.margeo.2021.106456

Circulação e Estrutura Vertical no Entorno do Arquipélago de Fernando de Noronha e Atol das Rocas

O GT3.0 (Variabilidade Climática, Ciclos Biogeoquímicos e Fluxo de CO2 no Oceano Atlântico Tropical) publicou em abril de 2021 um novo artigo na Frontiers in Marine Science (IF: 3.661) intitulado Surface Circulation and Vertical Structure of Upper Ocean Variability Around Fernando de Noronha Archipelago and Rocas Atoll During Spring 2015 and Fall 2017″ de autoria de Alex Costa da Silva, Alexis Chaigneau, Alina N. Dossa, Gerard Eldin, Moacyr Araujo e Arnaud Bertrand

ABSTRACT

Using current, hydrographic and satellite observations collected off Northeast Brazil around the Fernando de Noronha Archipelago and Rocas Atoll during two oceanographic cruises (spring 2015 and fall 2017), we investigated the general oceanic circulation and its modifications induced by the islands. In spring 2015, the area was characterized by lower SST (26.6◦C) and deep mixed-layer (∼90 m). At this depth, a strong current shear was observed between the central branch of the eastward flowing near-surface South Equatorial Current and the westward flowing South Equatorial Undercurrent. In contrast, in fall 2017, SST was higher (∼28.8◦C) and the mixed-layer shallower (∼50 m). The shear between the central South Equatorial Current and the South Equatorial Undercurrent was weaker during this period. Interestingly, no oxygen- rich water from the south (retroflection of the North Brazil undercurrent) was observed in the region in fall 2017. In contrast, we revealed the presence of an oxygen-rich water entrained by the South Equatorial Undercurrent reaching Rocas Atoll in spring 2015. Beside these global patterns, island wake effects were noted. The presence of islands, in particular Fernando de Noronha, strongly perturbs central South Equatorial Current and South Equatorial Undercurrent features, with an upstream core splitting and a reorganization of single current core structures downstream of the islands. Near islands, flow disturbances impact the thermohaline structure and biogeochemistry, with a negative anomaly in temperature (−1.3◦C) and salinity (−0.15) between 200 and 400 m depth in the southeast side of Fernando Noronha (station 5), where the fluorescence peak (>1.0 mg m−3) was shallower than at other stations located around Fernando de Noronha, reinforcing the influence of flow-topography. Satellite maps of sea- surface temperature and chlorophyll-a confirmed the presence of several submesoscale features in the study region. Altimetry data suggested the presence of a cyclonic

O artigo foi acessado no formato “Open Access”e pode ser acessado no seguinte “link”: https://doi.org/10.3389/fmars.2021.598101

Variabilidade Sazonal de Camarões Planctônicos na Plataforma Continental do Amazonas

O GT2.2 (Variabilidade Espaço-Temporal da Diversidade e Estrutura Trófica do Ambiente Pelágico na Plataforma Continental) tem uma novo artigo publicado no Journal of the Marine Biological Association of the United Kingdom (FI: 1.181) intitulado Factors affecting the seasonal variability of planktonic shrimps (Dendrobranchiata) along an estuary–ocean gradient on the Amazon continental shelf” de autoria de Leiliane Souza da Silva, Danielle Viveiros Cavalcante-Braga, Caio Brito Lourenço, Ralf Schwamborn e Jussara Moretto Martinelli-Lemos.

ABSTRACT

Dendrobranchiata shrimp taxonomic composition and spatial and temporal distribution on the Amazon continental shelf (ACS) were investigated along a transect between the sources of the Amazon and Pará Rivers, encompassing an extension of !250 km towards the contin- ental slope. Plankton was collected with oblique trawls (200 !m mesh size), and nine taxa were found; 59.4% were larvae (mysis or decapodid stages) and 40.6% were juveniles or adults. Acetes was negatively related to chlorophyll-a and temperature, and Luciferidae were posi- tively correlated with months. This study provides novel information on the density distribu- tion of dendrobranchiate shrimps, thus helping to pave the way to characterize a large-scale, hugely relevant area that is poorly studied. As in other tropical coastal areas, there is here an increase in number of taxa with increased distance from the coast. Luciferidae, Solenoceridae and Penaeidae were the most frequent families whereas Sicyoniidae and Sergestidae had the lowest frequency of occurrence nearer the slope. Despite the low larval density of penaeid shrimps, their presence in all months and at all sampling sites along the ACS proves the importance of this area for shrimps with socioeconomic relevance, as well as its importance as a nursery and growth habitat for dendrobranchiate shrimps.

O trabalho completo pode ser acessado em:

https://doi.org/10.1017/S0025315421.000308

ou solicitando diretamente a autora correspondente: Jussara Moretto Martinelli-Lemos, e-mail: jussara@ufpa.br

Erosão Costeira no delta do Parnaíba

Saiu publicado no periódico Ocean and Costal Management (IF=2.482) um novo trabalho no âmbito do inctAmbTropic Fase II intitulado “Evaluation of decadal shoreline changes along the Parnaíba Delta (NE Brazil) using satellite images and statistical methods” de autoria de Thiago Augusto Bezerra Ferreira , André Giskard Aquino da Silva, Yoe Alain Reyes Perez, Karl Stattegger e Helenice Vital, que investiga o comportamento da linha de costa do delta do Parnaíba no período 1984-2017. O trabalho concluiu que a redução na descarga fluvial do rio Parnaíba entre 1995-1999 e 2009-2012 foi a causa principal do recuo erosivo experimentado pelo delta.

Comportamento da linha de costa do delta do Parnaíba entre 1984-2017. Vermelho: erosão. Verde: progradação.

ABSTRACT

This study investigated changes of the shoreline position in the Parnaíba River Delta (PRD), which is in an underdeveloped and sparsely populated area. The general behavior of the shoreline between 1984 and 2017 was analyzed using 12 Landsat satellite images and the Digital Shoreline Analysis System (DSAS) software. DSAS applied statistical methods, such as Weighted Linear Regression (WLR) and End Point Rate (EPR), to define whether the shoreline was retreating or accreting. Data analysis revealed that, on a decadal time scale (33 years), 52% of the PRD shoreline retreated under erosional conditions, while 48% accreted. Accretion mainly occurred at the vicinities of the river mouth, especially eastward where the highest progradation rate was observed (maximum of 29 m/year). Shoreline retreat, up to 9 m/year, occurred predominantly in the western part of the PRD and away from the river mouth. However, changes of the general behavior of the shoreline (retreat/accretion) were observed at an inter- decadal time scale, which were positively related to variations in river discharge. Variations of river discharge are directly dependent on the rainfall amount along the drainage basin that, in this region, is controlled by climatic conditions such as El Niño and La Niña. Therefore, the reduced river discharge observed between 1995- 1999 and 2009–2012 (El Niño periods), was the major cause the triggered the observed coastal retreat (>6 m/ year) on PRD shoreline during these periods. Consequently, the variability of natural factors, such as river discharge and rainfall, are the main drivers of shoreline changes on PRD, since anthropogenic impacts have hitherto only marginal effects on the delta region and on the drainage basin of the Parnaíba river.

O trabalho completo pode ser acessado em: https://doi.org/10.1016/j.ocecoaman.2020.105513

Cânion do São Francisco: nova publicação do inctAmbTropicII

Saiu publicado na revista Geomorphology (IF = 3.819) um novo trabalho no âmbito do inctAmbTropic Fase II intitulado “Continuous canyon-river connection on a passive margin: The case of São Francisco Canyon (eastern Brazil)” de autoria de Rafael Fonseca Ribeiro, José Maria Landim Dominguez, Alana Aderne Santos, e Adriane Gonçalves de Araújo Nunes Rangel. Este trabalho investiga a origem do cânion do São Francisco à partir da integração de levantamentos com batimetria multifeixe, sísmica 3D e trabalhos anteriores publicados por pesquisadores do inctAmbtropic, além de aprofundar o conhecimento sobre a região do delta do São Francisco. Também apresenta pela primeira vez um mapeamento detalhado do talude superior na região.

Localização do cânion do São Francisco e sua relação com o delta homônimo.

Principais feições mapeadas no cânion do São Francisco e regiões vizinhas do talude superior.

ABSTRACT

Submarine canyons play a major role in sediment transfer to the deep sea. When connected with fluvial systems, they can produce large submarine fans, whose sandy bodies have a high potential as petroleum reservoirs. Although canyon-river connections are common on passive margins during lowstands, they are rare during highstands. So far, the only canyon in the Western South Atlantic to have exhibited continuous river connection throughout the Quaternary, regardless of sea level position, is the São Francisco Canyon (SFC) in eastern Brazil. In this study, we used multibeam and 3D seismic records integrated with previously published data to investigate the reasons for the continuous canyon-river connection in the area of the São Francisco River. The SFC comprises two compartments: The Upper and the Mid Canyon. The Upper Canyon indents 15 km of the shelf and acts as an erosive feeder trunk to the São Francisco Submarine Fan. When it emerges on the continental slope (Mid Can- yon), depositional processes dominate; the canyon now begins to meander and the thalweg is bordered by nu- merous terraces and levees. Five stratigraphic units have accumulated in the region of the canyon head since the beginning of the Oligocene. Initially, sedimentation had a uniform aggradational character (Unit 1), which later became more discontinuous in association with the development of reef build-ups (Unit 2) and of a low-lying area around the canyon head. This depression was partially infilled by siliciclastics (Unit 3) and later incised by a precursor of the SFC (Unit 4). The depression still has a morphological expression in the shelf nowadays as a bathymetric low (BL), within which the São Francisco River has built its delta (Unit 5). We hypothesize that the origin and evolution of the SFC is associated with three main factors: (i) breaching by the canyon head of thick carbonates rimming the shelf break; (ii) development of the shelf depression referred above; and (iii) major continental drainage reorganization. Continuous canyon-river connection was ensured by this shelf de- pression, which helped funnel siliciclastic sediments to the canyon and precluded lateral changes to the lower river trunk. Morphological features, such as axial incision of mass movement deposits is suggestive of some, although very limited, modern canyon activity. This case study contributes to a better understanding of river- basin sediment pathways, particularly on passive margins, which are of great importance for the successful ex- ploration of submarine fan systems.

O trabalho completo pode ser acessado em: https://doi.org/10.1016/j.geomorph.2020.107549

Participação do inctAmbTropicII no PGGM

Saiu agora em novembro o número especial da Geo-Marine Letters, comemorativo dos 50 anos do PGGM (Programa de Geologia e Geofísica Marinha). Este número especial reune 23 trabalhos de pesquisadores brasileiros principalmente na área da geologia e geofísica marinha. Oito destes trabalhos são contribuições dos GTs 1.1 e 2.1 do inctAmbTropic. Os trabalhos e respectivos links encontram-se listados abaixo:

Shallow sedimentation of Natal shelf and coastal erosion implications, NE Brazil

https://link.springer.com/article/10.1007/s00367-019-00594-y

Structural controls on the morphology of an extremely narrow, low-accommodation, passive margin shelf (Eastern Brazil)

https://link.springer.com/article/10.1007/s00367-019-00605-y

Organic matter in the deltaic clinoform of the São Francisco River (Eastern Brazil)

https://link.springer.com/article/10.1007/s00367-019-00607-w

Quantifying the high coastal dynamics of tropical mesotidal barrier island-spit systems: case study in Northeast Brazil

https://link.springer.com/article/10.1007/s00367-019-00610-1

Geodiversity as an indicator to benthic habitat distribution: an integrative approach in a tropical continental shelf

https://link.springer.com/article/10.1007/s00367-019-00614-x

Antecedent topography controls preservation of latest Pleistocene-Holocene transgression record and clinoform development: the case of the São Francisco delta (eastern Brazil)

https://link.springer.com/article/10.1007/s00367-019-00609-8

The Santo Antônio Bank: a high-resolution seismic study of a deflected ebb-tidal delta located at the entrance of a large tropical bay, eastern Brazil

https://link.springer.com/article/10.1007/s00367-019-00624-9

Statistical approach on mixed carbonate-siliciclastic sediments of the NE Brazilian outer shelf

https://link.springer.com/article/10.1007/s00367-019-00625-8

Padrões de diversidade de peixes recifais ao longo da costa tropical brasileira

Pesquisadores integrantes do Inct AmbTropic II, do Gupo de Trabalho 1.2 Recifes e ecossistema coralinos, acabam de publicar o artigo “Diversity patterns of reef fish along the Brazilian tropical coast” na revista científica Marine Environmental Research.

Nesse trabalho eles estudaram 100 recifes ao longo de 2.000 km da costa para entender como se distribui a diversidade de peixes nos recifes de coral do Brasil.

“Descobrimos que a maior parte das espécies são raras, geralmente ocorrendo em número reduzido ao longo de toda costa, exceto em determinados tipos de recifes onde foram mais abundantes.

Essa grande proporção de espécies raras revela uma maior vulnerabilidade das comunidades de peixes recifais. Nem compreendemos o potencial danoso de perder estas espécies, pois várias delas são muito pouco estudadas, justamente por serem difíceis de achar. Ao conseguirmos determinar que estes peixes preferem certos recifes, podemos identificar quais locais são prioritários para dedicar esforços e assim garantir sua conservação.”

Se você se interessou sobre o trabalho, ele estará disponível em https://authors.elsevier.com/a/1bcDTW5UJDWLr até o dia 10 de outubro, para download livre de cobranças. Após este período, você poderá acessar o artigo em www.doi.org/10.1016/j.marenvres.2020.105038 mas você pode ser cobrado pelo acesso à versão completa do trabalho.

English version

In our work “Diversity patterns of reef fish along the Brazilian tropical coast”, recently published in Marine Environmental Research, we studied a hundred reefs spanning 2.000 km over the tropical Brazilian coastline, aiming to understand how the diversity of Brazilian coral reef fishes is distributed. We found out that most species are rare, occurring in reduced numbers in most sites, but that in some types of reefs they had higher abundances. This greater proportion of rare species reveals a higher vulnerability of reef fish communities. We cannot discern the deleterious implications of losing rare species yet, as they are barely studied because they are hard to find. Nevertheless, as we determine types of reefs they prefer, we can identify priority sites to dedicate measures to assure their conservation.

If you are interested in this work, you can get full access to the article at https://authors.elsevier.com/a/1bcDTW5UJDWLr

This link will be available until October 10th and you are welcome to read or download. No sign up, registration or fees are required. After this period, you can access our paper at www.doi.org/10.1016/j.marenvres.2020.105038 but you can be charged to access the full version of the manuscript.

Panorama da erosão costeira

A linha de costa é uma região extremamente instável, sujeita a grandes mudanças em função de variações no padrão de ondas, no balanço de sedimentos, no nível do mar, ou como consequência de obras costeiras. Apesar dessas mudanças ocorrerem em diferentes escalas de tempo e espaço, estratégias simples de gestão para a ocupação da linha de costa, baseadas em estudos de longo prazo, podem minimizar prejuízos econômicos e ambientais.

É o que sugere o estudo Panorama da Erosão Costeira realizado sob os auspícios do Ministério do Meio Ambiente. Um grupo de pesquisadores do Instituto de Geociências da UFBA, alguns dos quais integrantes do inctAmbTropic, foram responsáveis pelo estudos dos litorais dos estados de Alagoas, Sergipe e Bahia. Segundo esse estudo, embora a tipologia de comportamento da linha de costa dominante nos três estados seja a de aparente “equilíbrio”, 26% do litoral alagoano (75 km), 50% do litoral sergipano (90 km) e quase 20% do litoral baiano (200 km) foram considerados como de elevada variabilidade e portanto instáveis, oferecendo assim um alto risco para ocupação humana – essas regiões estão principalmente associadas a desembocaduras de rios e canais de maré.

A recomendação é clara, nos trechos em que a linha de costa apresenta uma elevada variabilidade, a ocupação deve ser evitada, ou até mesmo proibida. Estas áreas são as mais instáveis e, na maior parte das vezes, é muito difícil prever o seu comportamento a longo prazo. Áreas como estas que ainda não estão ocupadas, poderiam ser destinadas à criação de unidades de conservação.

Nos trechos em aparente “equilíbrio”, onde o comportamento da linha de costa é mais previsível, o estabelecimento de faixas de recuo “non aedificandi” minimizaria em grande parte os problemas futuros de erosão. Embora essas áreas sejam mais estáveis, ainda assim, estão sujeitas a variações na posição da linha de costa decorrentes, por exemplo, de eventos extremos associados a tempestades.

Quer conferir a situação da sua praia? Acesse o trabalho completo no link.