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 21 for “"N:P ratios"”.
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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
… P, C and N concentrations, and lower C:N and C:P ratios. Legumes appeared to have a more efficient nutrient uptake strategy. However, the higher N:P ratio of legumes suggests that despite higher absolute nutrient concentrations, legumes were P limited. This study confirms that legumes are more P …
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The Role of Nitrogen and Phosphorus in the Growth, Toxicity, and Distribution of the Toxic Cyanobacteria, Microcystis aeruginosa
… dominating aquatic ecosystems in low N:P atomic ratios less than 44:1, the reliability of N:P ratios as a tool for managing and predicting <em>M. aeruginosa </em>blooms is explored through analyzing the specific roles of N and P in influencing its growth, toxicity, and distribution. N is far more …
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Recruitment from resting stages among bloom-forming cyanobacteria
… dominance is often correlated with low N:P ratios. Accordingly, I found that recruitment rates of cyanobacterial resting stages were increased at declining N:P ratios. A plausible explanation to my result is that a declining N:P ratio signals improving nutrient conditions for cyanobacteria …
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Non-Native Leaf Litter Modifies Algal Resources with Effects on Tadpole Growth
… and Chinese privet decreased periphyton N:P ratios and stimulated tadpole growth compared to native leaf litters. However, tadpole mortality in Japanese honeysuckle was high over winter compared to other leaf litters. Different litter species affected periphytic algal quality and quantity …
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The influence of land use on the quality of seston in southern Appalachian stream ecosystems
… in more disturbed streams, and C:N and N:P ratios of seston were higher in forested streams. Microbial respiration and instantaneous growth rates of C. tentans were highest on residential seston, indicating seston from those streams was more bioavailable. These results indicate that 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
… e.g., "black" and "orange" mats, and soil N:P ratios. The underlying soil microbial communities did not exhibit significant differences in diversity between the two tills, but community composition varied significantly across gradients of soil chemistry, particularly extractable-phosphate …
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Factors affecting root system response to nutrient heterogeneity in forested wetland ecosystems
… not P-rich patches, even though litterfall N:P ratios were > 15, which suggested that these ecosystems were P-limited. The combination of nutrient and oxygen heterogeneity affected root proliferation and biomass growth of three common floodplain forest species (Liquidambar styraciflua, Fraxinus …
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The Use of Algal Assays to Evaluate Algal Biomass in Regulated Streams
… stations during most sampling periods. Using N:P ratios, phosphorus is most often the limiting factor in the river. Above- and below reservoir differences in algal productivity were not distinct. Samples taken from the station below Saylorville Reservoir responded more frequently to nutrient …
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The Effects of Food Quality and Temperature on Mesozooplankton Physiology
… food quality in terms of phytoplankton organic ratios N:P, C:N and C:P and fatty acid content, on Temora longicornis feeding, respiration, and egg production rates (EPR). Maximum metabolic rates, assimilation efficiency and gross growth efficiency coincided with an optimum diet of ~16N:1P …
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Conservation of Nitrogen via Nitrification and Chemical Phosphorus Removal for Liquid Dairy Manure
… to dairy farmers regarding adjustment of N:P ratios so that manure can be applied to meet nutrient needs of crops while adhering to regulations set forth by nutrient management plans.
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Community and ecosystem analysis of forests recovering from landslide disturbance: White Mountain National Forest, New Hampshire
… Foliar and litterfall nutrient content, and the ratios of the macro nutrients, P, K, Ca and Mg with N are compared to observe potential nutrient imbalances and limitation. Litter decay and nutrient dynamics illustrate relative cycling rates of these elements across the chronosequence. Significant …
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Interactive effects of hemlock mortality and nitrogen availability on nutrient pools and fluxes in the southern Appalachian Mountains
… all elevation classes, hardwood foliar N:P ratios were lower in stands with declining hemlocks, suggesting trees are incorporating available P into biomass. Higher foliar N and P concentrations as well as observed increases in the growth of hardwood species in high elevation stands post-HWA …
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Factors Influencing the Spatial and Temporal Distrubtion of Primary Productivity and Community Respiration in the Mississippi Coastal Estuarine Region
… study, consistently low dissolved inorganic N:P ratios (average N:P < 4.3 for all stations) suggest that rates ofNetPP were nitrogen limited, while the NetPP rates measured in the Mississippi Sound showed periodic growth limitation due to low watercolumn light availabi lity. Measured RESP rates …
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The mechanisms behind alternative community states: Understanding producer composition in temporary and semipermanent wetlands
… In the observational work, N, P, and N:P ratios all were associated with producer community composition. I manipulated the three variables in enclosures in two experimental ponds with floating and submerged plants. I found N supply rates drove these patterns more strongly than P and N:P. …
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Organic nitrogen uptake by marine algae: consequences for marine ecosystem functioning and biodiversity
… areas, altered nitrogen to phosphorus (N:P) ratios, and changes in the inorganic to organic balance of the nutrient pools. Organic N can constitute up to 69 % of the total N pools, respectively, making it crucial, to understand the cycling of this fraction in coastal waters, and how changes …
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Effects of Freshwater Salinization and Associated Base Cations on Bacterial Ecology and Water Quality
… in nitrogen and phosphorus uptake increased N:P ratios in ambient water, especially in mesocosms with elevated Ca2+, which could affect nutrient limitation in salinized streams enriched with Ca2+. Bacterial community structure based on Bray-Curtis dissimilarity was not correlated to pairwise …
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Physiological and behavioral diagnostics of nitrogen limitation for the toxic dinoflagellate Alexandrium fundyense
… as well as C:N, toxin content and composition. Ratios of different toxin derivatives were identified that increased with increasing N-stress and appear to be sensitive and robust indicators of N-status. Once indicators were developed for N-stress, variability in toxin content and composition …
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The importance of dissolved organic nutrients in the biogeochemistry of oligotrophic gyres
… Indian ocean basin is characterized by low N:P ratios both in the inorganic and organic fractions with respect to phytoplankton nutrient requirements driven by an excess of denitrification over N2 fixation. The strongly non-Redfieldian TON:TOP ratio suggests a decoupling of TON and TOP …
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Investigating groundwater derived nutrient fluxes within Tauranga harbour, New Zealand
… isotopes (assumed groundwater related) and N:P ratios. This demonstrated that SGD has major implications for primary production, including recurrent algal bloom events which commonly occur in the harbour. While higher loads of inorganic and organic nitrogen from surrounding water catchments are …
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Shelf biogeochemical interactions and feedback processes in the Benguela upwelling system
… shelf due to luxury nutrient uptake. High N:P ratios occur at the stations at 21ᵒS than off Walvis Bay and are attributed to the presence of nutrient-rich, oxygen depleted SACW and denitrification respectively. Increased fixed nitrogen deficits (N*) occur in surface and subsurface waters at …
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