Navegando por Assunto "Aquecimento global"

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Acesso aberto (Open Access)
A aplicação da cromatografia gasosa acoplada (GC-FID), isótopos estáveis, palinologia e razão C:N na reconstituição paleoambiental de manguezais do Estado da Bahia e Espírito Santo.
(Universidade Federal do Pará, 2024-07-30) SILVA, Fernando Augusto Borges da; ALBERGARIA-BARBOSA, Ana Cecília Rizzatti de; http://lattes.cnpq.br/2666263256585897; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
Mangroves depend on ideal geomorphological, geochemical, and climatic factors to develop. Brazil, with its highly indented coastline under tropical and sub-tropical climate regimes, presents suitable conditions for the establishment of these ecosystems and distribution. The dynamics of these mangroves can be influenced by factors related to climatic variations and changes in hydrodynamic flow, resulting in modifications in sediment input and the origin of organic matter. These changes can be observed throughout the Holocene in different regions in of the country. On the northeast and southeast coast, the evolution of these ecosystems is associated with fluctuations in relative sea level (RSL) and sedimentary dynamics, while in the southern region, the change in the distribution of mangroves is a reflection of fluctuations in the RSL and climate changes caused by warming global. Recent studies seek to describe the evolution of these environments based on the elemental and isotopic characterization of organic matter. These constitute important tools in paleoenvironmental reconstruction. However, it is necessary to remember that the comparative analysis of the largest possible number of independent parameters is relevant as it adds value to the research and increases the reliability of the data to be analyzed, generating more precise information. Therefore, aiming to unravel the dynamics of organic matter in mangrove environments, as well as understanding movements of expansion and/or contraction of these ecosystems, analyzes of nalkanes were carried out using chromatography (GC-FID), associated with the sedimentary study, pollen data, isotopic and elemental analyses, synchronized with 14C and 210Pb dating, which allowed obtaining information about past biogeochemical processes and environmental changes during the Holocene and Anthropocene in the coastal plain at the mouth of the Itapicuru river (BA) and at the mouth of the Barra Seca and Jucu rivers (ES). Thus, the results of this research are presented in five scientific articles. The first, see chapter III, deals with the expansion of mangroves at the mouth of the Itapecuru river (BA) during the Anthropocene. The second scientific article (chapter IV) deals with the dynamics of mangroves at the mouth of the Barra Seca River, on the northern littoral of the State of Espírito Santo. The third article (chapter V) discusses the palynology tool used to understand the dynamics of coastal vegetation.The fourth article (chapter VI) presents the environmental changes that occurred at the mouth of the Jucu River, on the central coast of the State of Espírito Santo. Finally, the fifth article presents the results of n-alkanes analyses, compared with isotopic, elemental, palynological data, and 14C dating on the coastal plain of the Barra Seca River.
Acesso aberto (Open Access)
Efeitos das mudanças climáticas nos limites austral e boreal dos manguezais americanos durante o Holoceno e Antropoceno
(Universidade Federal do Pará, 2021-09-08) RODRIGUES, Érika do Socorro Ferreira; KAM, Biu Liu; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
During the Holocene, mangrove distributions were primarily controlled by climate change and sea level fluctuations. In particular, low winter temperatures in the subtropical coastal areas limited these ecosystems to expand beyond 30°N and 28°S in the North and South Hemisphere. Therefore, under the continuous warming trend during the Anthropocene, mangroves are expected to migrate to more temperate regions previously occupied by saltmarshes (e.g., Spartina sp.). The purpose of this Thesis is evaluate the effects of climate changes and SLR fluctuations on the distribution of American mangroves along the Holocene and Anthropocene, based on satellite and drone images, sedimentary facies, diatoms, pollen, geochemistry (LOI, XRF, TOC , TN, TS, C: N, C: S, δ13C and δ15N) as well 210Pb and 14C datings .To achieve the aforementioned objectives, studies were conducted on the tropical coast of southeastern Brazil - south of the Espírito Santo State (20°41'S), the subtropical coastal regions located on the north (26°6'S) and south (28°29’ S) coast of Santa Catarina, and Louisiana littoral (29° 09' N). The results of this research are presented in four scientific papers. The first one (see, chapter II) deals with the effects of global warming on the establishment of mangroves in the Louisiana littoral (29° 09’ N) during the Holocene. The second scientific paper (see, chapter III) shows southward migration of the austral limit mangroves in South America, according to the increase in minimum winter temperatures in the Anthropocene (southern Santa Catarina coast, 28°29' S). The third manuscript (see, chapter IV) assesses the impacts of sea level rise on tropical mangroves in southeastern Brazil (southern Espírito Santo coast, 20°41'S) during the Holocene and Anthropocene, using a multi-proxy approach. The fourth scientific paper (see, chapter V) addresses the establishment of mangroves in the São Francisco do Sul Bay (north Santa Catarina coast , 26° 6'S), in response to global warming in the last 1000 years. The results indicated a marine transgression off the southern coast of Santa Catarina (28°29’ S) and the Louisiana littoral (29°09’ N) during early Holocene. This natural process converted a lake into lagoons colonized by herbs adapted to an estuarine environment. On the Brazilian tropical coast, the middle Holocene high sea-level stand (2-5 m above the current level) was decisive for the establishment of mangroves. This comportment was observed in an estuary located on the south coast of Espírito Santo (20°41'S) where a herbaceous plain was gradually replaced by a lagoon surrounded by mangroves between ~6300 cal yr BP and ~4650 cal yr BP. However, between ~ 4650 cal yr BP and 2700 cal yr BP the lagoon colonized by mangroves on its margins was converted to a tidal flat occupied by herbs, palms and trees/shrubs reflecting the reduction of estuarine influence in the late Holocene, according to with the fall and/or stabilization of the RSL. From the last thousand years there has been a significant decrease in the occurrence of mangrove pollen in the sediments of the tidal flats of southern Espirito Santo (390 cal yr BP (1560 AD) and 77 cal yr BP (1873 AD), probably caused by a RSL fall associated with Little Ice Age (LIA). Paleoclimatic studies have indicated temperature fluctuations during LIA (380 to 50 cal yr BP) and MCA – Medieval Warm Period (950 to 750 cal yr BP) in the late Holocene and consequent change in the Brazil southern vegetation. These climatic events probably influenced the appearance of the mangrove genera succession in the São Francisco do Sul Bay (north Santa Catarina coast, 26°6' S). The effects of the sea level fall and/or stabilization during late Holocene were recorded on the southern coast of Santa Catarina (Laguna, 28° 29 ′ S) through changes in coastal geomorphology. In this same period at the Louisiana coastline (29°09 ′ N), sandy sediments (overwash sediments) were deposited in these estuaries reflecting the gradual migration of these sediments towards land likely a result of storm events. The position of RSL on the southern Brazilian coast (Laguna, 28° 29 ′ S) and north american (Louisiana coast, 29° 09 ′ N) from the middle Holocene were the same presenting suitable physicochemical conditions for mangrove development, as occurred on the coast of Espírito Santo (~6300 cal yr BP) and São Francisco do Sul Bay (~1500 cal yr BP). However, no mangrove pollen grains were recorded in the sediments of the current austral (Laguna, 28° 29 ′ S) and boreal (Louisiana coast, 29° 09 ′ N) limit of American mangroves during the Holocene. During this time interval, there was a significant contribution of organic matter of estuarine source in tidal flats occupied by Spartina sp. Regarding to global warming and RSL rise during Anthropocene an increase mangrove pollen of Espírito Santo sedimentary cores (20° 40' S) reflected mangrove migration to topographically higher sandy plains previously dominated by herbaceous vegetation. Regarding Laguna mangroves (current southern limit of the American mangroves, 28° 29 ′ S), pollen analyzes, 14C and 210Pb datings indicated that the mangroves were established under estuarine influence between ~1957 and 1986 AD, represented by Laguncularia sp. trees. Spatio-temporal analyzes based on satellite and drone images indicated that mangroves have been expanding in recent decades with the introduction of new mangrove genera. In our study area in São Francisco do Sul Bay (north coast of Santa Catarina, 26°6' S), palynological analyzes and 14C dating revealed that mangroves were established around ~ 1500 cal yr BP represented by Laguncularia sp. followed by Avicennia sp. (~500 cal yr BP) and Rhizophora sp. in the last century. This mangrove succession genera were likely caused by a warming trend in South America during the late Holocene and Rhizophora sp. by warming during the Anthropocene. In relation to the mangroves located on the Louisiana littoral, historical records indicated the presence of small shrubs of Avicennia sp. at the beginning of the 20th century. Currently, remote sensing studies coordinated by Cohen (2021) indicate a latitudinal expansion of Avicennia sp. colonizing areas that were previously occupied by Spartina sp. after two decades of warm winters. Therefore, mangroves migrated from the tropics to temperate zones as winter minimum temperatures increased during the Holocene. The Laguna and Louisiana mangroves (currently South and North American mangroves limit) were only established in the early and mid-21st century, respectively. Such dynamics were likely caused by the natural global warming of the Holocene and intensified during the Anthropocene. This process also caused a RSL rise which resulted in the migration of mangrove from lowlands to new higher tidal flats.
Acesso aberto (Open Access)
O futuro dos quelônios amazônicos no contexto das mudanças climáticas
(Universidade Federal do Pará, 2023-04) SILVA, Iago Barroso da; FAGUNDES, Camila Kurzmann; http://lattes.cnpq.br/7942655716698636; MASCHIO, Gleomar Fabiano; http://lattes.cnpq.br/7967540224850999; https://orcid.org/0000-0002-9013-4437
Assessing the effects of global warming on species distribution is largely necessary for understanding its consequences on biodiversity. Based on knowledge about the current and expected effects of climate change in the Amazon and in the chelonian group, this study used species distribution models to understand the consequences of these changes in the potential areas of species occurrence, answering the following questions: 1) Which regions and what is the extent of the distribution of Amazonian chelonians that will be experienced by future climate changes? 2) Which species will be most impacted? As a result, we observed that the models presented considerable performances. They stand out as, as projections of potential distributions in the current period, the wide distribution of the species Chelonoidis denticulatus; C. carbonarius and Platemys platycephala. For future climate scenario projections, all lost species are potential. Phrynops tuberosus (87.69%), M. nasuta (82.51%), P. platycephala (45.16%), M. raniceps (43.96%), P. sextuberculata (38.69%), C denticulatus (36.19%) are the species that most lost area in this scenario. For a more extreme future scenario, the species that lost the greatest potential area are M. nasuta (98.93%), P. tuberosus (97.87%), P. erythrocephala (66.26%), M. raniceps (63.46%), C. denticulatus (61.62%). Chelonians are animals that are very protected by the hydrological dynamics of water bodies, which will be especially impacted in the Amazon, avoiding changes in flow, precipitation, humidity, extent of flooding and the intensity of phenomena in different seasons of the basin. These changes will bring deleterious effects to chelonians, which depend on the river level and the area and period of flooding for reproduction and feeding. Chelonians with semiaquatic habits also lose very important feeding areas with the change in the hydrological regime and the landscape around the rivers. Very worrying is the fact that all species of turtles in the Amazon will be affected by climate change, with the vast majority losing large areas of suitable environmental areas for their occurrence. Mitigation actions, in the long term, at different scales, are essential to soften the effects of this scenario and contribute to the preservation of these species.
Acesso aberto (Open Access)
O mecanismo de desenvolvimento limpo como mitigador do aquecimento global e a participação do Brasil
(2009-06) COTA, Raimundo Garcia; REIS, Maria Aparecida Martins Cardoso; VALE, Lorena Alves do
This study of economic-environmental relevance emerges from the problem of the Global Environment in order to analyze the Mechanism of Clean Development (MCD) as an efficient tool, which can contribute to the mitigation of the Greenhouse Effect Gases (GEG) through the fulfilling of emission reduction goals pre-established by Kyoto Protocol. One examines the participation of Brazil as a hosting country of MCD projects. One concludes that, although the implementation of the MCD reduces the global cost of reduction of greenhouse gases emissions by developed countries and supports initiatives which promote sustainable development, the lacking of major specificity in the rules of the mechanism can open precedents to the right of polluting. One understands that the mechanism cannot be restricted only to the fulfillment of goals, but it is fundamental that it works as discouragement of pollution in its origin, according to the proposal of sustainability, north of the weather environmental policy.
Acesso aberto (Open Access)
Potencial do sequestro de carbono em plantio de dendezeiros para compensar a emissões de gases de efeito estufa no processo produtivo de óleo de palma.
(Universidade Federal do Pará, 2017-03-24) CHINGUEL LABAN, Duber Orlando; VASCONCELOS, Steel Silva; http://lattes.cnpq.br/0719395243841543; https://orcid.org/0000-0003-2364-8822; ARAÚJO, Alessandro Carioca de; http://lattes.cnpq.br/6188087583954899; https://orcid.org/0000-0002-7361-5087
Currently, the oil palm plantations are expanding in the Brazilian Amazon, where there are the optimal conditions for their development. The limitation of culture is an important factor for the maintenance of primary areas in the Amazon. Therefore, to know the characteristics of the culture within a productive context it is necessary to apply methodologies that help the executors of the companies to take into account the carbon emissions of the product. Some studies have been adopting methodologies to determine the greenhouse gas emissions emitted in the palm oil production process, through life cycle assessment applications. In this scenario, this work estimated the carbon stocks in the hybrid palm Interspecific (HIE) (Elaeis oleifera cortés x Elaeis guineensis jacq) over 25 years (productive time of the palm) and later to inventory greenhouse gas emissions from the palm oil production process at Marborges SA. The values show to hybrid palm oil, a carbon sequestration of 0.49 Mt CO2 in 25 years and emissions from the productive process are recorded at 0.39 Mt CO2eq. In addition, it was estimated that in the native vegetation areas of the company, the sequestration registered 4.5 Mt CO2, more than the palm plantations. Finally, it can be concluded that within the environmental context the compensation of the gases emitted in the production process of palm oil should happen in pasture areas only or areas without vegetation allied to the maintenance of the native vegetation.
Acesso aberto (Open Access)
Potencial do sequestro de carbono em plantios de dendezeiros para compensar as emissões de gases de efeito estufa no processo produtivo de óleo de palma
(Universidade Federal do Pará, 2017-03-24) LABAN, Duber Orlando Chinguel; VASCONCELOS, Steel Silva; ARAÚJO, Alessandro Carioca de
Currently, the oil palm plantations are expanding in the Brazilian Amazon, where there are the optimal conditions for their development. The limitation of culture is an important factor for the maintenance of primary areas in the Amazon. Therefore, to know the characteristics of the culture within a productive context it is necessary to apply methodologies that help the executors of the companies to take into account the carbon emissions of the product. Some studies have been adopting methodologies to determine the greenhouse gas emissions emitted in the palm oil production process, through life cycle assessment applications. In this scenario, this work estimated the carbon stocks in the hybrid palm Interspecific (HIE) (Elaeis oleifera cortés x Elaeis guineensis jacq) over 25 years (productive time of the palm) and later to inventory greenhouse gas emissions from the palm oil production process at Marborges SA. The values show to hybrid palm oil, a carbon sequestration of 0.49 Mt CO2 in 25 years and emissions from the productive process are recorded at 0.39 Mt CO2eq. In addition, it was estimated that in the native vegetation areas of the company, the sequestration registered 4.5 Mt CO2, more than the palm plantations. Finally, it can be concluded that within the environmental context the compensation of the gases emitted in the production process of palm oil should happen in pasture areas only or areas without vegetation allied to the maintenance of the native vegetation.
Acesso aberto (Open Access)
Representações sociais de aquecimento global por professores de ciências
(Universidade Federal do Pará, 2013-06-07) SANTANA, André Ribeiro de; NAKAYAMA, Luiza; http://lattes.cnpq.br/3771896759209007
Through the present study sought to characterize social representations of global warming for science teachers (Biology, Physics and Chemistry). Applied 70 questionnaires and interviewed 10% of target. The results showed that 97% of respondents blame man for global warming. However 50% of this amount portrays him as both a victim of climate events usually represented catastrophically. The media strongly influence these social representations, therefore claiming long working hours, my informants’ base their knowledge on the content of news magazines and TV programs; only 6.8% reported doing the same interactions with their peers in the school. Three peculiarities characterized allusions to reality Amazon: extreme emphasis on human dependence on the natural environment; associations of the manifestations of global warming with the forest and the waters; distancing weather events impacting and tragic. When approached everyday belenense global warming was associated with the phenomena with which it is possible to live: intensification of rainfall and heat. In terms of anchoring, were associations of global warming with the ozone layer, greenhouse gases and air pollution. Regarding the objectification, global warming was presented as planetary-scale ecological imbalance, and 21.4% of my informants perceive as punitive response of Nature to human actions. One thought was consensual: there is no cease global warming, but environmental education focused on the preservation of the environment helps to mitigate, stabilize and live with their demonstrations. These understandings are part of everyday school specific forms, as evocations of examples in program content related to global warming, or heights of projects. This understanding remained in Central Nucleus of social representations of global warming, as opposed to the option and arguments related to human action. Among the categories members of the peripheral system, lack of awareness, extensively linked to human action, was positioned near the central as well as deforestation, category more often, and burned, both accounting for most of the associations of the Central Nucleus reality Amazon. Lacks noteworthy that, like all social representations, the global warming constitute ways of dealing with reality, guiding communication processes, aggregate relationships and strengthen the cohesions of a social group, in my case, consisting of science teachers. These factors associated with knowledge "ecologizados" fragmented and superficial the specifics of global warming can justify improvement initiatives initial training and ongoing, which may be promoted continuously, at school through the pedagogical coordination. Accordingly, in addition to content updates, instigate urges science teachers, respecting and their experiences with the exercise of reflection on scientific knowledge and the media, something that could impact the way we perceive, think and deal with the global warming mentioned by my informants.
Acesso aberto (Open Access)
A transposição didática no ensino de física: o aquecimento global como objeto de estudo
(Universidade Federal do Pará, 2013-05-22) SILVA, Edilene da Silva e; ALMEIDA, Ana Cristina Pimentel Carneiro de; http://lattes.cnpq.br/1265908866509687
This research aims to highlight the epistemological model which is adopted by professor of Physics at the approach to the topic Global Warming (GW) classes in the second year of high school. In this perspective, it has been the main objective is to investigate how the internal didactic transposition of the theme GW in physics teaching within the teaching practice, looking for the answer to the following question: How physics teachers conceive epistemological models relating to GW? For this we use a qualitative approach with a case study with eyes on three physics teachers who teach in public schools in the city of Fortaleza. Data collection used the questionary, semistructured interview and finally the observation of lessons. Data analysis was complemented by the school adopted textbooks and didactic materials used by teachers. These analyses revealed that the knowledge of physics and design of epistemological models belong to the praxeological dimension of each teacher as epistemological models Natural and Anthropogenic GW influence the characterization of teaching models. These models are born in each text knowledge achieved in the classroom. The textbooks do not determine the upper bound of the form role models in class and yes, contribute to the formation of physical models. On the other hand, there is the possibility of redeeming features of the two epistemological models when discussing the issue of natural climate GW associated to human action, and that means to say that there is a correlation opinions seeking answers in two models epistemological reference and ending on the issue of global warming prove to be the reason for global warming in praxeology teachers research subjects.