Navegando por Assunto "Mangroves"

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Acesso aberto (Open Access)
dinâmica da vegetação durante o quaternário tardio no limite continental da península bragantina, litoral amazônico
(Universidade Federal do Pará, 2022-11-25) MACIEL, Giordana Leticia Monteiro; ASP NETO, Nils Edvin; http://lattes.cnpq.br/7113886150130994; https://orcid.org/0000-0002-6468-6158; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
The eastern Amazonian region is dominated and shaped by a macrotidal regime, harboring environments such as muddy plains colonized by mangroves, estuaries associated with tidal channels, floodplains, and macrotidal beaches, among others. To understand the vegetation dynamics and carry out the paleoenvironmental reconstitution in an Amazonian floodplain, palynological, sedimentary, and C-14 dating data were integrated based on a subsurface sedimentary profile collected in the region of the Taperaçu’s herbaceous fields, in the Bragança peninsula (PA), on the Amazon coast. The present study identified three fácies associations and four pollen zones that occurred during the Late Pleistocene and Holocene. The first facies association is defined as an alluvial deposit, which presented pelite facies, flaser heterolithic bedding with a coarsening upward sequence. The vegetation was predominantly typical of trees and shrubs, marked by the presence of Rubiaceae, Agavaceae, and Annonaceae families and with low herbaceous vegetation dominated by the Araceae family developed around 41,200- 39,975 cal years BP. The second facies association identified showed typical characteristics of a tidal channel, with a well-delimited erosive surface, which marks a transition in the processes operating over this environment; it comprises gravel, massive sand, and wavy-marked mud facies. Toward the Taperaçu’s tidal channel, herbaceous vegetation was developed, represented by Cyperaceae and Ulmaceae, and the presence of trees and shrubs, such as Arecaceae, Malphighiaceae, and Rubiaceae. During the early and mid-Holocene (6000-5915 cal years BP), at a depth of 6.45 m from the surface, the results revealed the formation of a tidal flat. The main pollen result during this phase was the establishment of mangroves, colonized by Rhizophora and Avicennia, in addition to the presence of herbaceous vegetation, which currently occupies the studied region, marking the late Holocene.
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)
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)
Três décadas de mudanças na planície costeira brasileira: O status dos manguezais, da aquicultura e salicultura a partir de séries temporais Landsat e técnicas de aprendizado de máquina
(Universidade Federal do Pará, 2020-03-31) DINIZ, Cesar Guerreiro; SOUZA FILHO, Pedro Walfir Martins e; http://lattes.cnpq.br/3282736820907252
Since the 1980s, land-use and land-cover (LULC) mapping has become a common scientific task. However, the systematic and continuous identification of any terrestrial use or cover, whether on a global or regional scale, demands large storage and processing capacities. This thesis presents two cloud computing pipelines to analyze: 1) the annual status of Brazilian mangroves from 1985 to 2018, along with a new spectral index, the Modular Mangrove Recognition Index (MMRI), which has been specifically designed to better discriminate mangrove forests from the surrounding vegetation, and 2) the annual status of the aquaculture and salt-culture over the Brazilian coastal plains. The mangrove cover showed two distinct occupation periods, 1985-1998 and 1999-2018. The first period shows an upward trend, which seems to be related more to the uneven distribution of Landsat data than to the regeneration of Brazilian mangroves. In the second period, a mangrove loss trend was registered, reaching up to 2% of the mangrove forest. On a regional scale, ~80% of Brazil's mangrove cover is located in the Amazon, Maranhao, Para, Amapa states. In terms of persistence, ~75% of the Brazilian mangroves remained unchanged for two decades or more, especially in the Brazilian Amazon. As for item 2, aquaculture and salt-culture are two of the most classical coastal land-uses worldwide. It isn't different in Brazil, where both land-uses are related to relevant economic activities in the Brazilian Coastal Zone (BCZ). However, to automatically discriminate such activities from other water-related covers/uses is not an easy task. Spectrally speaking, water is water and, unless it presents a high concentration of optically active compounds, not much can be done to dissociate a variety of water-related targets. In this sense, convolutional neural networks (CNN) have the advantage of predicting a given pixel's label by providing as input a local region (named patches or chips) around that pixel. Both the convolutional nature and the semantic segmentation capability allow the U-Net classifier, a type of CNN, to access the "context domain" instead of solely isolated pixel values. Backed by the context domain, the results obtained show that the BCZ aquaculture/saline ponds occupied ~356 km² in 1985 and ~544 km² in 2019, reflecting an area expansion of 52% (~185 km²), a rise of 1.5x in 35 years. From 1997 to 2015, the saline/aquaculture area grew by a factor of ~ 1.7, jumping from 349 km2 to 583 km2, a 67% increase. In 2019, the northeast sector concentrated 93% of the coastal aquaculture/salt-culture surface, 6% in Southeast and 1% in South. Interestingly, despite presenting extensive coastal zones and suitable conditions for developing different aquaculture products, the Amazon coast shows no relevant aquaculture infrastructure sign.