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 86 for “"nutrient limitation"”.
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Defining sources of nutrient limitation for tumors
… this, tumor cells must acquire various nutrients, and growth slows if these metabolites are not obtained in sufficient quantities. Importantly, the metabolic demands of cancer cells can be different from those of untransformed cells, and nutrient accessibility in tumors is different than …
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Effects of nutrient limitation on understory communities in a tropical forest
… peak in mid-elevation tropical forests. Soil nutrient limitation is an important factor influencing plant communities and yet little is known about the factors influencing fern floristic composition and functional traits in montane tropical forests. My dissertation compares composition …
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Mechanisms of nutrient limitation and nutrient acquisition in managed and unmanaged forest ecosystems
… the results of several investigations into nutrient acquisition processes in the forests of New Hampshire. I begin with a meta-analysis of fertilization studies showing that phosphorus (P) and calcium (Ca) as well as nitrogen (N) may limit primary production in deciduous forests of the …
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Nutrient Limitation of Upper Great Lakes Periphyton across Large Spatial and Environmental Gradients
… blooms requires an understanding of what nutrients limit algal growth and how nutrient limitation interacts with other parameters in the highly dynamic and spatially heterogeneous littoral zone. To assess the nutrient limitation status and its correlates for periphyton in the Upper Great …
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Algal growth potential and nutrient limitation in the Las Vegas Bay, Lake Mead, Nevada
… to determine algal growth potential (AGP) and nutrient limitation of the Las Vegas (LV) Bay of Lake Mead using the standard test organism Selenastrum capricornutum and the Lake phytoplankton. Results for the current nutrient levels in the LV Bay revealed that the AGP of the LV Bay waters, …
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Nutrient limitation dynamics of a coastal Cape Cod pond : seasonal trends in alkaline phosphatase activity
… activity (APA) were utilized in tandem as nutrient deficiency indicators (NDIs) for phytoplankton. The study objective was to evaluate the limiting nutrient status of the pond throughout the growing season. The development of a high throughput method for fluorometrically measuring APA …
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Nutrient limitation dynamics of a coastal Cape Cod pond : seasonal trends in alkaline phosphatase activity
… activity (APA) were utilized in tandem as nutrient deficiency indicators (NDIs) for phytoplankton. The study objective was to evaluate the limiting nutrient status of the pond throughout the growing season. The development of a high throughput method for fluorometrically measuring APA …
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The effect of nutrient limitation and oxidative stress on bromoform production from axenic cultures of marine diatoms
… of this study was to quantify the effect of nutrient limitation and oxidative stress on bromoform production from axenic cultures of marine diatoms.
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The effects of nutrient limitation and growth rate on the regulation of the multi-drug pump genes acrAB in escherichia coli
… rate, and this was irrespective of the limiting nutrient. This regulation was not OS_dependent as the expression of acrAB increases during stationary phase in the batch culture of an rpoS mutant. In the same rpoS mutant it was found that there was an even greater derepression of acrR …
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Chemical limnology, algal growth potential, and nutrient limitation factors of the Upper New River, Virginia, and predictions concerning trophic status for the proposed Blue Ridge reservoirs
… potential productivity of water in the basin. Nutrient limitation studies were conducted utilizing indigenous periphyton, indigenous plankton, and a selected, cultured organism (Selenastrum capricornutum). Uptake of ¹⁴C by indigenous periphyton and phytoplankton was greatest in river water …
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Algal Biomass Accrual in Relation to Nutrient Availability along a Longitudinal Gradient in the Upper Green River, Kentucky
Nutrient limitation in aquatic ecosystems results from a deficiency in nitrogen or phosphorus levels relative to cellular growth needs. Nutrient limitation of freshwater systems is a function of biotic and abiotic factors. Biotic factors include vascular and nonvascular plant community composition. …
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Context-dependent controls of periphyton across the littoral-benthic habitat of deep, clear lakes
… littoral-benthic production can include light, nutrients, and grazers, although, studies examining production across the photic zone in deep lakes are limited. This study investigates the role of nutrient limitation and inhibition from the shallow to deep (lower limit of the photic zone) …
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Characterisation of the effect of stress on nitrogen metabolism in the commercially important agarophyte, Gracilaria gracilis
… a number of abiotic and biotic factors, such as nutrient limitation, has virtually destroyed the G. gracilis resource. An understanding of the physiological response of the alga to nutrient limitation will aid in re-establishing and sustaining G. gracilis populations. However, modelling algal …
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Ecological forces affecting microbial eukaryotes in the coastal ocean
… of growth and death rates, which are impacted by nutrient availability (bottom-up control) and predation (top-down control). In this thesis, I investigate the effect of specific top-down and bottom-up forces at fine scales of time, location, and taxonomy, uncovering mechanisms by which nutrient …
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Nutrient constraints on plant community production and organic matter accumulation of subtropical floating marshes
… from external sediment subsidy and internal nutrient cycling controls plant productivity and organic matter accumulation. An interesting question is whether increased external nutrient loading can affect the basic processes that lead to peat formation—plant production and organic matter …
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The Effects of Whole Genome Duplication on Functional Traits and Interactions With Arbuscular Mycorrhizal Fungi
… tests the hypothesis that neopolyploids are more nutrient limited by comparing growth and leaf functional trait responses of diploids, neotetraploids, and established tetraploids of Heuchera cylindrica to different levels of nutrient supply. The results support the hypothesis that neopolyploidy …
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The Effects Of Whole Genome Duplication On Functional Traits And Interactions With Arbuscular Mycorrhizal Fungi
… tests the hypothesis that neopolyploids are more nutrient limited by comparing growth and leaf functional trait responses of diploids, neotetraploids, and established tetraploids of Heuchera cylindrica to different levels of nutrient supply. The results support the hypothesis that neopolyploidy …
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Characterizing water quality, nutrients, and dissolved oxygen dynamics in four Lake Ontario coastal wetlands
… ecosystems, yet their role in regulating nutrient loadings to receiving waters remains unclear. Over a decade of monitoring by the Toronto and Region Conservation Authority revealed that four wetlands (Rouge Marsh, Duffin’s Marsh, Carruthers Marsh, and Frenchman’s Bay) vary as net sinks or …
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Phytoplankton productivity of tropical Lake Chapala, Mexico.
… factor of areal phytoplankton productivity. Nutrient limitation was less important, although nitrogen may have become limiting during the dry season. Among stations, areal phytoplankton productivity varied inversely with turbidity and was decidedly seasonal. It was highest during the rainy …
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Absolute values only show part of the whole : evidence of P limitation in legumes in the CFR from N:P ratios
The influence of nutrient limitation in legumes and non-legumes was studied in the field, on nutrient poor and nutrient rich sites in the CFR in the western Cape of South Africa. 6 species of legume and 11 species of non-legume, along with their corresponding soils were taken for macro and …
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