In order to contribute to the discussion of Holocene climate changes, four sediment cores were collected from the northern Brazilian Amazonia lowland. These cores were studied through pollen analysis and sedimentary features, and the results were discussed within a chronological framework provided by radiocarbon dating. The cores were sampled from fluvial terraces representative of channel, floodplain/lake and crevasse splay deposits formed since the mid-Holocene. The pollen samples derive from floodplain/lake deposits and the pollen grains are mainly composed by families Moraceae, Euphorbiaceae, Caesalpiniaceae, Fabaceae, Rubiaceae, Melastomataceae, Combretaceae, Sapindaceae, Poaceae, Cyperaceae, Aizoaceae, Apiaceae and genus Sebastiana. The pollen data suggest no significant vegetation changes in the study area for the past 4808–4886 cal yr BP. This led to proposing stable climatic conditions since at least the middle Holocene. Such a finding is contrary to the occurrence of a dry period during the middle Holocene. The stabilization of the relative sea level about 6000 cal yr BP along the northern Brazilian littoral may have influenced the water table, and favored the establishment and maintenance of Amazonian lowland forest during the mid- and late Holocene. In addition, this process may have attenuated the impact of that dry period in areas under most fluvial influence.
Morphological descriptions were made for pollen grains and spores extracted from samples from three sedimentary sections-Chandless 1, Purus 10 and Purus 30-from fluvial terraces on the Chandless and Purus rivers, Acre State, Brazil. Level CH1-12 at Chandless 1 was C 14-dated to 4861-5050 cal yr BP, P10-3 of Purus 10 was dated through the OSL method at 8200 +/-65 yr BP, while P30-6 at Purus 30 was C 14 dated to 7845-7998 cal yr BP. For pollen analysis, 2 cm 3 of each sample was removed, treated with potassium hydroxide (KOH) and acetolysed, followed by palymorph separation with bromoform/alcohol density 2.0 solution. A total of 49 palynomorphs were morphologically described (39 pollen types and 10 Pteridophyte spores). The most frequent pollen types belonged to Anacardiaceae, Arecaceae, Euphorbiaceae, Fabaceae, Rutaceae and Amaranthaceae, while the most frequent spores belonged to Polypodiaceae and Pteridaceae. The pollen richness found in the studied samples reflects the current vegetation occupying the banks of the rivers.
Resumo:A avaliação dos impactos provocados pela agricultura é fundamental para o entendimento do nível de sua sustentabilidade. Nesse contexto, índices de sustentabilidade podem ser utilizados para medição, pois consistem em informações que facilitam a compreensão de dados. Este trabalho teve como objetivo realizar uma prospecção da utilização de índices para avaliação da sustentabilidade agrícola e apresentar uma visão geral das metodologias mais empregadas. Para isso, foram realizadas buscas sobre Índices de Sustentabilidade aplicados à Agricultura no banco de publicações científicas do Science Direct. A pesquisa coletou dados entre os anos de 2004 e 2015, em revistas de várias áreas. Os artigos foram analisados individualmente para certificação de que tratavam sobre o tema abordado. Foi encontrado um total de 496 resultados, sendo que destes, apenas 71 tratavam sobre a temática específica. O ano de 2015 foi o que apresentou maior porcentagem de artigos publicados. A China destacou-se com o maior número de publicações na área entre os anos da pesquisa, com um total de 24 artigos, enquanto o Brasil teve apenas 2 publicações para o mesmo período. Dentre as metodologias utilizadas, destaca-se o Índice Revista GEINTEC-ISSN: 2237-0722. Aracaju/SE. Vol.8, n.2, p.4357-4368, abr/maio/jun -2018 4358 D.O.I.: 10.7198/geintec.v8i2.920Sustentável de Emergia. Diante do número reduzido de manuscritos sobre a temática, conclui-se que este consiste em um assunto promissor para pesquisa e desenvolvimento.Palavras-Chave: desenvolvimento sustentável; metodologias; sistema agrícola; indicadores. Abstract:The assessment of impacts caused by agriculture is essential to understand the level of its sustainability. In this context, sustainability indexes can be used for measuring, because they consist of information that facilitate the understanding of data. This study aimed to conduct a prospection about the use of index to evaluate the agricultural sustainability and present an overview of the most commonly used methodologies. For this, searches were conducted on Sustainability Indexes applied to Agriculture in the bank of scientific publications of the Science Direct. The survey collected data between 2004 and 2015 in various areas magazines. The articles were analyzed individually for certification that they treated on the discussed topic. A total of 496 results were found, and of these, only 71 treated on the specific theme. The highest percentage of published articles occurred in 2015. China stood out with the highest number of publications in the area between the years of research, a total of 24 articles, while Brazil had only 2 publications for the same period. Among the methods used, Sustainable Emergy Index highlights. On the small number of manuscripts on the subject, it is concluded that this is a promising subject for research and development.
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