Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 46 for “"taxonomic composition"”.
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Effects of light and nutrient gradients on the taxonomic composition, size structure and physiological status of the phytoplankton community within a temperate eutrophic estuary
… Water. The size structure and species composition were investigated during 2002 and 2003, with special attention to nanophytoplankton (cells < 5µm in diameter). The main sampling stations were Empress Dock and NW Netley in both years, and Calshot and Horse Elbow in 2002 only. To aid the …
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The effects of nutrients and hydrology on periphyton and phytoplankton in Fraser River tributaries, British Columbia
… factors explain variation in algal biomass and taxonomic composition. July epilithic periphyton chlorophyll a was weakly correlated with TN, while October periphyton was significantly related to DP and conductivity. The phytoplankton biomass in July was best predicted by TP (r2 = 0.70, p ≤ …
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Coupling Metaproteomics with Taxonomy to Determine Responses of Bacterioplankton to Organic Perturbations in the Western Arctic Ocean
… change over time and space, and which taxonomic groups dominate distinct metabolic pathways, are essential to understanding the ecology of these microbiomes and the factors contributing to their regulation of elemental cycles in the oceans. The primary goal of this dissertation was to …
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Structural dynamics of community gene expression In a freshwater cyanobacterial bloom over a day-night cycle
… approach for quantifying changes in both the taxonomic composition (structure) and activity (function) of complex microbial systems in response to dynamic environmental conditions. We have used next-generation Illumina sequencing to characterize the metatranscriptome of a tropical eutrophic …
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Evolution and ecology of body size in North American terrestrial mammals during the Paleocene and Eocene transition
… and change points in the community structure, taxonomic composition, and climate. We found that an initial change in community structure correlated with the change in taxonomic composition. The other changes points in structure are correlated with changes in climate suggesting climate played a …
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Patterns, Processes And Models Of Microbial Recovery In A Chronosequence Following Reforestation Of Reclaimed Mine Soils
… characterize soil-microbial abundance, richness, taxonomic composition, interaction patterns and functional genes. Generally, microbial succession followed a trajectory along the chronosequence age, with communities becoming more similar to reference sites with increasing age. However, two major …
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Environmental DNA (eDNA) Metabarcoding: Analysis of Freshwater Macroinvertebrate Community Structure and Diversity
… metabarcoding, which can be used to identify the taxonomic composition of entire communities, has the potential to increase both survey efficiency and taxonomic resolution. In this study, I evaluated the efficacy of eDNA metabarcoding to document freshwater macroinvertebrate diversity in two …
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Fatty Acids as Biomarkers of Plankton Trophic Structure in Table Rock Lake, Missouri
… showed significant changes in fatty acid composition with season, as well as with location, but these differences were not always consistent with algae taxa. Taxonomic composition of the phytoplankton shifted in time, with diatoms and green algae dominant in June and cyanobacteria in …
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Assessing Subterranean Arthropod Diversity through COI Barcoding in Two Ecoregions of Southwestern Virginia, USA
… in these communities remains unknown, and their taxonomic composition and ecological diversity have scarcely been assessed. Subterranean pitfall traps are a commonly used method for sampling endogean and hypogean soil habitats in Europe but have never been widely implemented in North America. …
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Macroinvertebrate drift along an elevational and stream size gradient in a southern Appalachian stream
… were also highly correlated with drift density. Taxonomic composition of drift differed from that of the benthos, indicating drift was not simply random, but that taxa vary in the propensity to drift. Overall, this study found more evidence of temporal (diel and seasonal) drift patterns than …
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Species Richness and Ecological Diversity of Myxomycetes and Myxomycete-Like Organisms in the Tropical Forests of Brazil
… over the years. Furthermore, the majority of the taxonomic and ecological efforts to describe and protect the Brazilian tropical biodiversity are usually focused on macroorganisms while the knowledge regarding the heterogeneity of microorganism species that compose the Brazilian microbiota …
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The effect of soil nutrient availability on resource allocation in tropical tree species
… tree communities are diverse in both their taxonomic composition and in their functional strategies for resource use and acquisition. Soil resources influence productivity of tropical forests and the distributions of tree species across edaphically heterogeneous landscapes. My dissertation …
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The Direct and Indirect Effects of Insectivory by Birds in Two Neotropical Forests
… canopy of a seasonally dry forest. Moreover, the taxonomic composition of arthropods changed in the absence of bird predation, with greater densities of chewing arthropods where foliage was inaccessible to birds. Consequentially, leaf damage increased by 86% where foliage was inaccessible to bird …
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Understanding the development of gut microbiota and effect of Salmonella Typhimurium infection on gut microbiota in layers
… chickens. In chapter 2, the development and composition of gut microbiota of hens housed in a single aged cage farm was studied from hatch to week 75. These hens were reared in cages from day old. The results showed that the richness of gut microbiota increased with the age and stabilized …
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Vertical distributions of megafauna on inactive vent sulfide features correspond to their feeding modes
… Lucky's Mound and Sentry Spire, to determine how taxonomic composition and feeding traits vary with vertical position on the features. A total of 51 morphotypes, each categorized to feeding mode, was identified from three levels of the features (spire, apron, and base) and a section of the …
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Vertical distributions of megafauna on inactive vent sulfide features correspond to their feeding modes
… Lucky's Mound and Sentry Spire, to determine how taxonomic composition and feeding traits vary with vertical position on the features. A total of 51 morphotypes, each categorized to feeding mode, was identified from three levels of the features (spire, apron, and base) and a section of the …
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Influence of landscape-variation in geochemistry on taxonomic and functional composition of microbial mat communities in the McMurdo Dry Valleys, Antarctica
… on glacial tills of distinct age and mineral composition in Taylor Valley, Antarctica. Microbial mat and soil DNA were extracted and sequenced on an Illumina NextSeq500 in a 150 bp paired end format. Raw sequences were uploaded to the MG-RAST server for processing and annotation. Community …
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Submerged wood inhabiting macoinvertebrates of the Elm Fork of the Trinity River, Texas: Assemblage analyses, comparisons to the benthic fauna, and a study of Cyrnellus fraternus (Trichoptera: Polycentropodidae)
Taxonomic composition and spatio-temporal variability of macroinvertebrates inhabiting snags were examined from an 8-km segment of the Elm Fork of the Trinity River. Seventy-seven macroinvertebrate taxa were collected from submerged wood during the study. Assemblages were highly variable spatially …
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THE EVOLUTIONARY ECOLOGY OF HOST-MICROBIOME SYMBIOSIS IN ONTHOPHAGUS DUNG BEETLES
… to provide an in-depth assessment of the taxonomic composition of the gut microbiota of several dung beetle species, and to determine to what extent microbiome composition changes when hosts are introduced to novel geographic ranges. As a whole, my dissertation employs a diversity of …
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Effects of nitrogen-fixing symbiotic cyanobacteria on the microbial ecology of the coral, Montastraea cavernosa
… of diatoms. Their presence does not affect the taxonomic composition of the diverse coral-associated prokaryotic community, but such communities do exhibit significant geographic differences. Metatranscriptomic analysis of mRNA indicates that coral-associated prokaryotes, including …
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