Pedro Walfir Martins e Souza Filho

Recognition of the main geobotanical features along the Bragança mangrove coast (Brazilian Amazon Region) from Landsat TM and RADARSAT-1 data

Orbital remote sensing data were assessedfor mapping of the main geomorphologicaland vegetation units of the Bragançapeninsula (North Brazil), which belongs toa vast though sparsely mapped mangrovecoast. Wide wetland environmentscharacterize the region with extremevariations in extension, temporalevolution, and spatial complexity. Thiswork was based on different digitalprocessing techniques separately applied toLandsat TM and RADARSAT-1 images. Inaddition, both data were merged on apixel-to-pixel basis using algorithms,which rendered an enhancement of thecoastal landforms and a betterdiscrimination of wetlands and landformtypes. The interpretation of the integratedproduct, aided by field validation, made itpossible to significantly extend existingmapping. Nineteen geobotanical units wereidentified: estuarine channels, submergedsand banks, sandflats, old estuarinesandbanks, mudflats, ebb-tidal deltas,barrier-beach ridges, coastal dunes,chenier sand ridges, young intertidalmangroves, intertidal and supratidalmangroves, outer and inner marshes, fluvialflood plains, coastal plateau, degraded andregenerated mangroves, and an artificiallagoon. The digital integration of Fine RADARSAT-1 and Landsat TM data sensitivelyhighlighted geobotanical coastal features,providing a useful tool for a synopticanalysis of their natural and man-drivenchanges.Orbital remote sensing data were assessedfor mapping of the main geomorphologicaland vegetation units of the Bragançapeninsula (North Brazil), which belongs toa vast though sparsely mapped mangrovecoast. Wide wetland environmentscharacterize the region with extremevariations in extension, temporalevolution, and spatial complexity. Thiswork was based on different digitalprocessing techniques separately applied toLandsat TM and RADARSAT-1 images. Inaddition, both data were merged on apixel-to-pixel basis using algorithms,which rendered an enhancement of thecoastal landforms and a betterdiscrimination of wetlands and landformtypes. The interpretation of the integratedproduct, aided by field validation, made itpossible to significantly extend existingmapping. Nineteen geobotanical units wereidentified: estuarine channels, submergedsand banks, sandflats, old estuarinesandbanks, mudflats, ebb-tidal deltas,barrier-beach ridges, coastal dunes,chenier sand ridges, young intertidalmangroves, intertidal and supratidalmangroves, outer and inner marshes, fluvialflood plains, coastal plateau, degraded andregenerated mangroves, and an artificiallagoon. The digital integration of Fine RADARSAT-1 and Landsat TM data sensitivelyhighlighted geobotanical coastal features,providing a useful tool for a synopticanalysis of their natural and man-drivenchanges.

Avaliação de áreas deposicionais e erosivas em cabos lamosos da zona costeira Amazônica através da análise multitemporal de imagens de sensores remotos

Os cabos lamosos Cassipore e Orange no norte do Brasil constituem um ambiente dinâmico influenciado pelo rio Amazonas, onde as modificacoes na linha de costa estao sujeitas a severos processos de progradacao e erosao. Imagens de sensores remotos opticos e microondas foram coletadas de 1980 a 2003 e analisadas em um Sistema de Informacao Geografica (SIG), permitindo a identificacao e quantificacao da distribuicao espacial das areas de progradacao e retrogradacao ao longo da linha de costa. Durante este periodo, as maiores taxas de erosao ocorreram junto ao cabo Cassipore, com recuo medio de 27,5 metros de distância linear e erosao de 1,37 km2 de area de manguezal por ano. Por outro lado, os maiores indices de deposicao de sedimentos ocorreram no cabo Orange, onde a planicie costeira progradou 24,6 m ao ano, agregando 55,85 km2 de manguezal a linha de costa nos ultimos vinte e tres anos. Os mecanismos de progradacao determinaram um acrescimo na vegetacao de manguezal de 50,8% ao longo das tres ultimas decadas. Um balanco sedimentar realizado na area pesquisada demonstrou que predominam os processos construtivos (61,3%) sob os processos erosivos (38,7%).

Mapeamento de ambientes costeiros tropicais (Golfão Maranhense, Brasil) utilizando imagens de sensores remotos orbitais

Este trabalho apresenta os resultados do reconhecimento e mapeamento dos ambientes costeiros da regiao do Golfao Maranhense, Brasil, utilizando uma abordagem metodologica que incluiu: (a) analise integrada com base no processamento digital de imagens, opticas Landsat-4 TM e SPOT-2 HRV, de imagens SAR (Synthetic Aperture Radar) do RADARSAT-1, e dados de elevacao da SRTM (Shuttle Radar Topography Mission); (b) sistema de informacoes geograficas; e (c) levantamentos de campo relativos a geomorfologia, topografia e sedimentologia. Os ambientes costeiros, assim mapeados foram agrupados em quatro setores: Setor 1, com pântanos salinos, pântanos de agua doce, lagos intermitentes e canal estuarino; Setor 2, abrangendo tabuleiro costeiro, planicie de mare lamosa, planicie fluvial, planicie de mare arenosa, praias de macromare, area construida e lagos artificiais; Setor 3, com manguezal, paleodunas e planicie de mare mista; e Setor 4, constituido por dunas moveis. Alem disso, foram tambem reconhecidos lagos perenes, deltas de mare vazante e planicies de supramare arenosas. O processamento digital e a analise visual das imagens de sensores remotos orbitais, associados ao uso de sistemas de informacoes geograficas, mostraram-se eficazes no mapeamento de zonas costeiras tropicais, possibilitando a geracao de produtos com boa acuracia e precisao cartografica.

Fusão de dados multisensor para a identificação e o mapeamento de ambientes flúvio-estuarinos da Amazônia

Multisensor data fusion has been widely used in response to complementary nature of many data sets. This paper compares the results of four different data fusion methods used to merge Landsat-7 ETM+ and RADARSAT-1 Wide 1 data. The comparison was based on spectral characteristics of images using statistical and visual analyses of generated products. Four methods were used in the Landsat-7 ETM+ and RADARSAT-1 W1 data fusion: i) The best three bands combination(Landsat-7) based OIF (Optimum Index Factor) selection were merged with RADARSAT-1 data; ii) Decorrelation stretch was applied in the three bands (Landsat-7) selected by OIF and merged with RADARSAT-1 image; iii) PCA (Principal Component Analysis) to six reflective ETM+ bands (1, 2, 3, 4, 5 and 7) and posterior fusion of the three first Principal Components (PC1, PC2, PC3) with SAR; iv) A new approach SPC-SAR (Selective Principal Component - Synthetic Aperture Radar). The SPC-SAR product presented the best performance in the identification of coastal features and allowed the most effective enhancement of the different environments.

Reconhecimento e mapeamento dos ambientes costeiros para geração de mapas de ISA ao derramamento de óleo, Amazônia oriental

Acidentes relacionados ao transporte de petroleo constituem uma ameaca as zonas costeiras de todo o mundo, pois se trata de um evento ecologicamente desastroso podendo causar serios danos ao meio ambiente. Na costa nordeste do Para ocorre intenso fluxo de navios e balsas transportando petroleo e derivados, dai a necessidade de estabelecer estrategias de prevencao e gestao dos impactos ambientais ao derrame de oleo para elaboracao de planos de emergencia. O objetivo deste trabalho e gerar o mapa dos ambientes costeiros e o mapa de indice de sensibilidade ambiental ao derrame de oleo dos ambientes costeiros de uma porcao da costa nordeste do Para. A metodologia consistiu no processamento digital de imagens Landsat ETM+7, associadas aos dados do MDE do SRTM (shuttle radar topography mission) e aos dados de campo, em ambiente de SIG (sistema de informacao geografica). Os resultados permitiram o reconhecimento e a descricao de cinco unidades geomorfologicas e de ambientes sedimentares; identificacao e hierarquizacao de nove indices de sensibilidade ambiental (ISA); alem da geracao do mapa de indice de sensibilidade ambiental ao derramamento de oleo. As tecnicas de sensoriamento remoto e SIG mostraram ser importantes ferramentas no reconhecimento dos ambientes costeiros e geracao dos mapas propostos.

Análise faciológica e estratigráfica da planície costeira de Soure (margem leste da ilha de Marajó-PA), no trecho compreendido entre o canal do Cajuúna e o estuário Paracauari

A planicie costeira de Soure, na margem leste da ilha de Marajo (Para), e constituida por areas de acumulacao lamosa e arenosa, de baixo gradiente, sujeitas a processos gerados por mares e ondas. Suas feicoes morfologicas sao caracterizadas por planicies de mare, estuarios, canais de mare e praias-barreiras. A analise faciologica e estratigrafica de seis testemunhos a vibracao, com profundidade media de 4 m, e de afloramentos de campo permitiu a caracterizacao dos ambientes deposicionais, sua sucessao temporal e sua correlacao lateral, a elaboracao de secoes estratigraficas e a definicao de uma coluna estratigrafica. Foram identificadas cinco associacoes de facies: (1) facies de planicie de mare, (2) facies de manguezal, (3) facies de barra de canal de mare, (4) facies de praia e (5) facies de duna. A historia sedimentar da planicie costeira de Soure e representada por duas sucessoes estratigraficas: (1) a sucessao progradacional, constituida pelas associacoes de facies de planicie de mare, manguezal e barra de canal de mare; e (2) a sucessao retrogradacional, formada pelas associacoes de facies de praia e de duna. Essas sucessoes retratam uma fase de expansao das planicies de mare e manguezais, com progradacao da linha de costa (Holoceno medio a superior), e uma posterior fase de retrogradacao, com migracao dos ambientes de praias e dunas sobre depositos lamosos de manguezal e planicie de mare, no Holoceno atual. A historia deposicional da planicie costeira de Soure e condizente com o modelo de evolucao holocenica das planicies costeiras do nordeste paraense.

Mine land rehabilitation in Brazil: Goals and techniques in the context of legal requirements

Environmental legislation in many countries demands the rehabilitation of degraded areas to minimize environmental impacts. Brazilian laws require the restitution of self-sustaining ecosystems to historical conditions but ignore the emergence of novel ecosystems due to large-scale changes, such as species invasions, extinctions, and land-use or climate changes, although these novel ecosystems might fulfill ecosystem services in similar ways as historic ecosystems. Thorough discussions of rehabilitation goals, target ecosystems, applied methods, and approaches to achieving mine land rehabilitation, as well as dialogues about the advantages and risks of chemical inputs or non-native, non-invasive species that include all political, economic, social, and academic stakeholders are necessary to achieve biological feasibility, sociocultural acceptance, economic viability, and institutional tractability during environmental rehabilitation. Scientific knowledge of natural and rehabilitating ecosystems is indispensable for advancing these discussions and achieving more sustainable mining. Both mining companies and public institutions are responsible for obtaining this knowledge.

Chemical Composition of the Bragantino Estuary Mangrove Sediment (PA) - Brazil

Geochemical and mineralogical characteristics of the mangrove sediments are inherited from source areas, continental and marine, through the contribution of particulate or ionic material brought by the currents. The objective of this study was geochemically to characterize the sediment of a mangrove forest in north estern Pará State (Brazil). The sediment showed a predominance of finer fraction (58% silt and clay) and high concentrations of minerals SiO2 and Al2O3. And the elements trace Pb, Mo, Ga, As, Rb, Cs, Ba, V, Ni, Co, Zn, Cu, Sc and Y showed the typical values found in the region. The mangrove area present chemical characteristics of a site that does not suffer from human disturbance. A more detailed study, taking into account the seasonal factor, would help in observing the behavior of the species.

Spatial distribution of southern brown shrimp (Farfantepenaeus subtilis) on the Amazon continental shelf: a fishery, marine geology and GIS integrated approach

The spatial distribution of the southern brown shrimp Farfantepenaeus subtilis (Perez-Farfante, 1967) was studied based on industrial fishing fleet activities and is associated with geological and oceanographic characteristics of the benthonic environments on the Amazon continental shelf. Using a geographical information system (GIS) this paper sought to calculate the relative abundance of brown shrimp based on catch per unit effort (CPUE) and compare it with bathymetry, type of sedimentary structure, sedimentation rate and bottom salinity. As a result, we have concluded that the relative abundance (in terms of CPUE) is not uniformly distributed in space. Spatial analysis indicates that commercial trawling efforts were made in the (foreset) region of the subaqueous Amazon delta at depths of 40 to 60 m. In this region, prawn are responsible for the bioturbation of the sediments and the creation of a sedimentary structure called mottled mud. In the foreset region, sedimentation rates progressively increased up to 10 cm.yr-1; re-suspension was reduced and bottom salinity was high (~ 36). It appears that all of these factors define a stable muddy area with intense bioturbation. This notable biological activity is to be explained by the occurrence of a high F. subtilis abundance that appears to originate in a microbial loop. We concluded that by combining fishery information with environmental data from a GIS, it was possible to identify abundance distribution patterns for southern brown shrimp and other economically important fishery resources and to understand how they change on a large spatial-scale.

Pollen morphology of the Poaceae: implications of the palynological and paleoecological records of the southeastern Amazon in Brazil

ABSTRACT A detailed assessment of Poaceae pollen morphology was performed using light and scanning electron microscopy (LM and SEM, respectively), digital image processing and multivariate data analysis of species from the montane savanna (canga vegetation) of the Serra dos Carajas region in the southeastern Amazon to discriminate the lower taxonomic levels and, accordingly, the habitat types of Poaceae. Poaceae pollen are generally stenopalynous monoporate grains with annulate and operculate pores, and distinguishing species by ornamentation using LM is impossible. Under SEM, Poaceae have mainly areolate microechinate/ granulose ornamentation, except for Eragrostis maypurensis (rugulate-microechinate), Andropogon bicornis, Trichanthecium parvifolium and T. polycomum (rugulate granulose), and Rhytachne gonzalezii (microechinate). Digital image processing of ornamentation under SEM coupled with multivariate data analysis allowed for differentiation between the E. maypurensis, R. gonzalezii, A. capillaris, Otachyrium versicolor, Paspalum carinatum and T. polycomum. Distinguishing species of the wet savanna, such as Isachne polygonoides, R. gonzalezii, O. versicolor, P. virgatum, and T. polycomum, from species of the dry savanna can improve paleoecological and paleoclimatic interpretations.