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Dissertação _Anna Beatriz Jones Oaquim_Digital.pdf: 6278668 bytes, checksum: 60236079c59e16ffdb171fe240dd8a21 (MD5) / Made available in DSpace on 2017-11-01T15:59:40Z (GMT). No. of bitstreams: 1
Dissertação _Anna Beatriz Jones Oaquim_Digital.pdf: 6278668 bytes, checksum: 60236079c59e16ffdb171fe240dd8a21 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / The use of diatoms as micropaleontological indicators has been used in the last decades, since these organisms that are sensitive to environmental changes, having their frustules preserved in the sediments, allow paleoenvironmental and / or paleoclimatic reconstructions. In this context, the present study aims to reconstruct regional climatic variations in the South Shetland Islands, located on the west coast of the Antarctic Peninsula, using a corer with 50cm sampled at the Glubokoe Deepe Proglacial Lake (62 ° 11,066'S, 58 ° 54,413'O), Fildes Peninsula, King George Island, based on the fossil record of diatoms. In qualitatively analysis on the sedimentary layers from the period 2013 to 1737, 34 taxa were found and identified, of which only 19 were considered as frequent. Among these 19 taxa the most abundant species along all layers was the centric diatom Aulacoseira glubokoyensis, a new species discovered throughout this study, followed by penate diatoms, which present a high diversity. Aulacoseira glubokoyensis showed a decrease in relative abundance and cell size in the period of higher ozone variation, probably associated to the adaptation to this environmental condition associated to the increase of UV-B radiation. Based on the correlations obtained between the environmental variables and the relative abundance of the frequent taxa, it was possible to establish three reconstruction models, one for temperature, the other for the average energy of cyclones occurring between 50 ° and 70 ° S and other for the minimum ozone content in the atmosphere. The first model of reconstruction was based on the relative abundance of Brachysira minor and Pinnularia sp. And presented an associated error of only 13%, the second in the relative abundance of Nitzschia cf. Kleinteichiana, Pinnularia borealis, Gomphonema sp. with an average error of 2% and the last one, of minimum ozone, was based in the relative abundance of Planothidium australe, Pinnularia borealis, Gomphonema sp. and Humidophila tabellariaeformis, with mean associated error of 11%. Thereby, for this region diatom assemblies can be used as paleoclimatic reconstructors / The use of diatoms as micropaleontological indicators has been used in the last decades, since these organisms that are sensitive to environmental changes, having their frustules preserved in the sediments, allow paleoenvironmental and / or paleoclimatic reconstructions. In this context, the present study aims to reconstruct regional climatic variations in the South Shetland Islands, located on the west coast of the Antarctic Peninsula, using a corer with 50cm sampled at the Glubokoe Deepe Proglacial Lake (62 ° 11,066'S, 58 ° 54,413'O), Fildes Peninsula, King George Island, based on the fossil record of diatoms. In qualitatively analysis on the sedimentary layers from the period 2013 to 1737, 34 taxa were found and identified, of which only 19 were considered as frequent. Among these 19 taxa the most abundant species along all layers was the centric diatom Aulacoseira glubokoyensis, a new species discovered throughout this study, followed by penate diatoms, which present a high diversity. Aulacoseira glubokoyensis showed a decrease in relative abundance and cell size in the period of higher ozone variation, probably associated to the adaptation to this environmental condition associated to the increase of UV-B radiation. Based on the correlations obtained between the environmental variables and the relative abundance of the frequent taxa, it was possible to establish three reconstruction models, one for temperature, the other for the average energy of cyclones occurring between 50 ° and 70 ° S and other for the minimum ozone content in the atmosphere. The first model of reconstruction was based on the relative abundance of Brachysira minor and Pinnularia sp. And presented an associated error of only 13%, the second in the relative abundance of Nitzschia cf. Kleinteichiana, Pinnularia borealis, Gomphonema sp. with an average error of 2% and the last one, of minimum ozone, was based in the relative abundance of Planothidium australe, Pinnularia borealis, Gomphonema sp. and Humidophila tabellariaeformis, with mean associated error of 11%. Thereby, for this region diatom assemblies can be used as paleoclimatic reconstructors
| Identifer | oai:union.ndltd.org:IBICT/oai:https://app.uff.br/riuff:1/5091 |
| Date | 01 November 2017 |
| Creators | Oaquim, Anna Beatriz Jones |
| Contributors | Albuquerque, Ana Luíza Spadano, Alba, José João Barrera, Moser, Gleyci Aparecida Oliveira, Silva, Heitor Evangelista da |
| Publisher | Niterói |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFF, instname:Universidade Federal Fluminense, instacron:UFF |
| Rights | info:eu-repo/semantics/openAccess |
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