Evidências sedimentares de antigo ambiente marinho, Montanhas Ellworth, Antártica Ocidental

O vale Elephant Head (79°.298’S / 83°20.426’W) é um vale deglaciarizado no qual amostras sedimentares foram coletadas em depósitos morâinicos. Análise do tamanho e morfometria das partículas, composição química e mineralógica foram efetuadas. O predomínio de carbonato de cálcio foi observado na maioria das amostras. Marcas onduladas (ripple marks) sugerem a existência de ambiente marinho raso. Um processo de sedimentação marinha preencheu possivelmente esse mar interior, associado com soerguimento tectônico local, posterior cobertura e ação glacial. Sedimentação calcária e clástica domina o vale, refletindo a natureza e composição das principais fontes de sedimentos. Os depósitos e sedimentos no vale Elephant Head corroboram com outros estudos que caracterizam a área como uma zona de rift em um ambiente sedimentar marinho raso. A principal lacuna é o timing desses eventos

Análisis Sedimentológico y geomorfológico de áreas lacustres en la Península Fildes, Isla Rey Jorge, Antártica Marítima

Geomorphological features and sedimentary characteristics are analized from five sets of shallow sediment cores collected in lakes in the Fildes Peninsula, King George Island. The geomorphology of the area was observed and sediments samples were obtained at field activities during the XXXI Brazilian Antarctic Operation (March-April/2013). Biogeochemical characteristics, physical parameters, mineralogical composition, particle size distribution, macroscopic characteristics of the sediments and satellite images were analized. Preliminary results indicate climatic and environmental changes in north-south transect of the peninsula. The mineralogical composition is associated with geological structure of the area, where basaltic rocks predominate. The particle size variation reflects different sediment source environments. Macroscopic analysis and mineralogical composition variation reflect the action of weathering along the peninsula. The sediments also have potential mineralization and subsequent release of greenhouse gases. A preliminary map of the classification of the lakes is presented. In addition, it was identified that wetland sediment presents methane production rates (CH4) about 40 times larger and more sensitive to the effect of global warming compared to lake sediment. Subpolar aquatic ecosystems sediments from Maritime Antarctica can be a preferential site for the effects of climate variability

O uso público da praia de Grumari – RJ: caracterização dos visitantes

O objetivo do trabalho foi caracterizar o perfil dos visitantes da praia de Grumari, durante o período de agosto de 2015 a julho de 2016. Foi possível identificar o nível de percepção dos usuários sobre a praia, assim como suas preferências e críticas. Para uma análise mais precisa os dados foram segmentados por estações do ano, pois assim, foi possível particularizar, de modo sazonal, o perfil dos visitantes. De um modo geral, o público se mostrou rotineiro, visto que 43% frequenta a praia mais de dez vezes ao ano, são instruídos e oriundos da Zona Oeste da cidade (67,50%). Apresentou ter um conhecimento superficial que a praia estava localizada em uma unidade de conservação (48,50%), o tempo médio de permanência foi de 2 a 6 horas, já o tamanho dos grupos foi, majoritariamente, formado por 2 a 4 pessoas (75%). A principal atividade eleita foi o banho de mar (53%), sendo o mar a maior atrativo. O público se mostrou indiferente ou pouco informado sobre os problemas encontrados na praia (38%), o entendimento sobre a importância da restinga para a praia foi caracterizado como superficial (40%). No verão constatou-se que os visitantes são pouco informados, descentralizados regionalmente, com o maior número de pessoas que visitam a praia pela primeira vez e os maiores grupos. No outono foi identificado um público com maior conhecimento sobre a importância da restinga, mais assíduos na visitação, o maior número de pessoas que estão desacompanhadas e os que mais pediram por segurança. Na estação do inverno foi observado o menor número de pessoas com nível superior (35,14%) e o maior com ensino médio (64,86%). Na primavera, o público foi caracterizado com o maior nível superior (65,22%) e, juntamente com o verão, apresentou o menor conhecimento sobre a unidade de conservaçãoThis study aimed to characterize the profile of visitors of Grumari beach between August 2015 and July 2016. It was possible to identify the level of perception of users on the beach, as well as their preferences and options. For a more accurate analysis, the data were segmented by seasons. This way, it was possible to particularize the profile of visitors seasonally. In general, the public seemed to be regular because 43% of it go to the beach more than ten times a year, they are educated and they are from west zone of the city (67.50%). The visitors seemed to have superficial awareness that the beach was in a conservation unit (48.50%), the mean stay time was between 2 and 6 hours, and the groups were mainly composed of 2 to 4 people (75%). The main activity chosen by them was the sea bath (53%) because the beach was considered the most attractive point. The public showed itself indifferent or little informed about the problems found on the beach (38%), the understanding about the importance of sandbank to the beach was characterized as superficial (40%). In the summer, it was verified that the visitors are little informed, regionally decentralized, with the largest number of people visiting the beach for the first time and the with the largest groups. In the autumn, the public showed more knowledge about the importance of sandbank and it is more assiduous and it is in that season that people go to the beach by themselves and the one who asked for more safety. In the winter, it was observed the lowest number of people with a higher education (35.14%) and the highest number with high school education (64,86%). In the spring, the public was characterized with the highest education level (65.22%) and, with summer, it presented the least knowledge level about the conservation uni

Análisis Sedimentológico y geomorfológico de áreas lacustres en la Península Fildes, Isla Rey Jorge, Antártica Marítima

Geomorphological features and sedimentary characteristics are analized from five sets of shallow sediment cores collected in lakes in the Fildes Peninsula, King George Island. The geomorphology of the area was observed and sediments samples were obtained at field activities during the XXXI Brazilian Antarctic Operation (March-April/2013). Biogeochemical characteristics, physical parameters, mineralogical composition, particle size distribution, macroscopic characteristics of the sediments and satellite images were analized. Preliminary results indicate climatic and environmental changes in north-south transect of the peninsula. The mineralogical composition is associated with geological structure of the area, where basaltic rocks predominate. The particle size variation reflects different sediment source environments. Macroscopic analysis and mineralogical composition variation reflect the action of weathering along the peninsula. The sediments also have potential mineralization and subsequent release of greenhouse gases. A preliminary map of the classification of the lakes is presented. In addition, it was identified that wetland sediment presents methane production rates (CH4) about 40 times larger and more sensitive to the effect of global warming compared to lake sediment. Subpolar aquatic ecosystems sediments from Maritime Antarctica can be a preferential site for the effects of climate variability