216 resultados para Dardanus insignis


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Planktonic foraminiferal diversity, equitability and biostratigraphic analysis of samples from Ocean Drilling Program (ODP) Leg 122, Hole 762C show that in general, cool water conditions prevailed during the latest Campanian-Maastrichtian in the eastern Indian Ocean. This is indicated by planktonic foraminiferal assemblages characterized by low species diversity and equitability with abundant rugoglobigerinids and heterohelicids. Archaeoglobigerinids, globigerinelloids, hedbergellids, and long-ranging double-keeled globotruncanids are also present in varying abundance but single-keeled forms occur rarely and sporadically. Identification of the stage and zonal boundaries for the studied geologic interval have been achieved through biostratigraphic analyses of closely spaced samples. Three planktonic foraminiferal biozones were identified, namely; in stratigraphic order, the Heterohelix rajagopalani, Contusotruncana contusa and Abathomphalus mayaroensis Zones. In Hole 762C, a Transitional Realm with Austral influences is defined for the latest Campanian to Maastrichtian, as shown by the high relative abundance of fauna characteristic of Transitional and Austral Realms. Austral endemic species such as Archaeoglobigerina australis Huber and Hedbergella sliteri Huber were found in the samples studied but Globigerinelloides impensus Sliter andA rchaeoglobigerina mateola Huber are conspicuously absent. From the latest Campanian to middle Maastrichtian, cooler parts of the Transitional Realm prevailed. A slight warming trend is assumed towards the end of the middle Maastrichtian because the faunas contain more species indicative of warm water conditions. The late Maastrichtian also appears to have been warmer than the latest Campanian-middle Maastrichtian. This conclusion is based on the high diversity and equitability values and recognition of some thermophilic taxa. A Tethyan influence is inferred for the latest Maastrichtian on the basis of an increase of planktonic foraminiferal species diversity and occurrences of several keeled taxa.

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About 80 species of spores and pollen grains were recorded during detailed palynological investigations of selected Lower Cretaceous sections from Holes 638B and 638C and the bottom of Hole 641C. Most of them are long-ranging taxa with worldwide distribution. However, on the Iberian margin and in the southern European basins, Trilobosporites canadensis, Trilobosporites bernissartensis, Parvisaccites amplus, Foveosporites subtriangularis, and Ephedripites multicostatus seem to be index species of the Valanginian to late Aptian interval. Clavatipollenites was not recovered in the Barremian marginal marine sediments.

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The study of diatoms in core HC11 collected from the southwestern part of Chukchi Sea, allowed to distinguish 3 diatoms ecological zones, reflecting paleoenvironmental changes during the last 2300 years. The sediment age was based on the sedimentation rates, determined by 210Pb and radiocarbon dating of mollusk shells. The environmental changes of Chukchi Sea revealed by examination of diatoms correlates with global climate changes - the warming of the early and middle Subatlantic and cooling of the late Subatlantic (Little Ice Age). Warming early and middle Subatlantic in the Chukchi Sea was probably stronger than the warming of the late 20th century and was not accompanied by significant changes in sea level.

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Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Zoologia, 2015.

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Os Sistemas Agroflorestais (SAF?s), consistem no cultivo simultâneo de espécies lenhosas e agrícolas em um mesmo espaço geográfico, no intuito de obter maior oferta de produtos, garantir a segurança alimentar e otimizar o espaço rural, permitindo uma produção sustentável. O presente trabalho consistiu da implantação de um SAF com frutíferas nativas, no município de Igarapé-açu-PA, em área de produtor rural com atividade econômica baseada no cultivo de mandioca. As espécies foram o murucizeiro, o bacurizeiro e o camucamuzeiro, as quais estão sendo avaliadas por meio do desempenho morfoagronômico de clones. No murucizeiro, os tratamentos que se destacaram para altura da planta foram o São José (1,76m), Cristo (1,61m) e Maracanã-2 (1,59m); que também apresentou maior volume de copa (3,09m3). O plantio das sementes pré-germinadas de bacurizeiro apresentou uma eficiência na emergência e desenvolvimento de 82%. As mudas de camu-camu que se destacaram foram as os clones CPATU-1, 2 e 9.