171 resultados para FIMBRIATA


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Calcareous nannofossils are abundant in the Paleogene sediments recovered during Ocean Drilling Program Leg 120. Although no continuous Paleogene section was obtained, Sites 747 through 751 complemented each other so as to provide a virtually complete composite stratigraphic section. The calcareous nannofossil biostratigraphy at Sites 747, 748, and 749 is discussed. Correlation of calcareous nannofossil biozones and magnetozones at these sites suggests some diachrony with low-latitude areas, as well as on a regional basis. Changes in calcareous nannofossil diversity throughout the Paleogene are analyzed and interpreted as reflecting major paleoclimatic events.

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Question: How do interactions between the physical environment and biotic properties of vegetation influence the formation of small patterned-ground features along the Arctic bioclimate gradient? Location: At 68° to 78°N: six locations along the Dalton Highway in arctic Alaska and three in Canada (Banks Island, Prince Patrick Island and Ellef Ringnes Island). Methods: We analysed floristic and structural vegetation, biomass and abiotic data (soil chemical and physical parameters, the n-factor [a soil thermal index] and spectral information [NDVI, LAI]) on 147 microhabitat releves of zonalpatterned-ground features. Using mapping, table analysis (JUICE) and ordination techniques (NMDS). Results: Table analysis using JUICE and the phi-coefficient to identify diagnostic species revealed clear groups of diagnostic plant taxa in four of the five zonal vegetation complexes. Plant communities and zonal complexes were generally well separated in the NMDS ordination. The Alaska and Canada communities were spatially separated in the ordination because of different glacial histories and location in separate floristic provinces, but there was no single controlling environmental gradient. Vegetation structure, particularly that of bryophytes and total biomass, strongly affected thermal properties of the soils. Patterned-ground complexes with the largest thermal differential between the patterned-ground features and the surrounding vegetation exhibited the clearest patterned-ground morphologies.

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During "Meteor"cruise 1965 the author collected 134 samples of surface sediments from the Iranian part of the Persian Gulf. Benthic Foraminifera populations have been analysed for determining their depth zonation. These data are supposed to allow detailed depth interpretation of Pleistocene sediments found in cores. In addition, the ecological information might be usefull to reconstruct the depositional environment of fossil sediments in similar shallow epicontinental seas. The investigation is published in two parts: the present part 1 contains the catalogue of species with short discussions of taxonomic problems, notes on the distribution within the Persian Gulf and 11 plates, partly with scanning electron micrographs. The results of the statistical analysis are given in data tables which include number of species, percentages of 2 (and 5) ranked species, standing crop and foraminiferal numbers. The author used "species groups" to avoid ambiguities with species requiring additional taxonomic studies. However, species numbers within these units are estimated to yield applicable diversity information. - A total of 52 species and 7 "species groups" were separated, 2 new species were described.