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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

An assessment of present and historical (1984-2012) Lake Diefenbaker water clarity and chlorophyll-a concentration using Landsat imagery

2014 December 1900 (has links)
Abstract: The use of earth observing satellites can be an effective supplement or alternative to traditional field sampling. The Landsat series of satellites have been particularity useful in assessing water quality in lakes, oceans, and reservoirs. This study utilized Landsat 5 and 7 imagery to model Secchi disk depth (SDD) and chlorophyll-a concentrations (Chl-a) at Lake Diefenbaker, Saskatchewan. I used data from these Landsat satellites to answer the following questions: First, can models that predict water quality (SDD and Chl-a concentration) be developed for Lake Diefenbaker using Landsat imagery? Second, can these models identify trends that have taken place at the reservoir from 1984-2012? Third, can I determine if ephemeral events like algal blooms or flooding have an effect on the reservoir? Novel models were developed from data collected in 2011 and 2012 that could predict SDD and Chl-a concentrations in the reservoir (linear regression, model I). These models explain less variation than comparable studies, but the loss in explanatory power is made up by their ability to predict data from any Landsat image of the reservoir. My study showed that predicted SDD and Chl-a concentration were positively related, an atypical relationship in freshwater systems. During the archive study period (1984-2012), both mean seasonal SDD and mean seasonal Chl-a have significantly decreased throughout the reservoir (p<0.05, regime-shift analysis). Spatially, the greatest decrease in SDD was closest to the major inflow the SSR, while downstream areas in the reservoir have decreased minimally. There was a decline in Chl-a concentrations that was spatially consistent throughout the reservoir. There was a significant negative relationship between flow rate and both water clarity and Chl-a concentrations (P<0.05, model II linear regression). Algal blooms occurred sporadically throughout the study period. There were blooms in 9% of images analyzed. Blooms typically occurred in the Qu’Appelle arm of the reservoir in the late summer and fall. The water quality data extracted by this study can be useful to many future studies, as historical data is absent for much of the reservoir’s history.
272

Productivity and carbon accumulation potential of transferred biofilms in reclaimed oil sands-affected wetlands

Frederick, Kurt R. 06 1900 (has links)
Biofilms are significant contributors to primary production, nutrient cycling, bio-stabilization and the food web of wetland ecosystems. Photoautotrophic biomass (PB) and primary production (PP) were determined for biofilms exposed to various treatments and materials in wetlands near Fort McMurray. Biofilm additions and oil sands process-affected materials were expected to increase the microbial colonization rates on treated substrates and subsequently PB and PP of biofilms over time as compared to controls and unaffected materials. Biofilms survived the transfers and colonized new substrates immediately. Oil sands process affected materials were found to increase PB and PP throughout the first year. A strong decreasing trend for both PB and PP in treatment microcosms occurred in year two, eventually coalescing with control conditions at a lower equilibrium. Transferred biofilms and treatment materials, therefore, increased overall wetland productivity during the initial stages of wetland development when growing conditions are most limiting. / Land Reclamation and Remediation
273

Dependence of stomatal conductance on leaf chlorophyll concentration and meteorological variables

Matsumoto, Kazuho, Ohta, Takeshi, Tanaka, Takafumi 09 1900 (has links)
No description available.
274

Nutrients and chlorophyll dynamics in Fort Cobb Reservoir

Lakish, Benjamin. January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 31, 2008) Includes bibliographical references.
275

Photo-protective function of carotenoids in photosynthesis

Amarie, Sergiu Unknown Date (has links) (PDF)
Frankfurt (Main), Univ., Diss., 2009 / Erscheinungsjahr an der Haupttitelstelle: 2008
276

Physiological and molecular studies on silicon-induced cadmium tolerance in rice (Oryza sativa l.)

Nwugo, Chika Charles. January 2008 (has links)
Thesis (Ph. D.)--Miami University, Dept. of Botany, 2008. / Title from second page of PDF document. Includes bibliographical references (p. 115-131).
277

Using band ratio, semi-empirical, curve fitting, and partial least squares (PLS) models to estimate cyanobacterial pigment concentration from hyperspectral reflectance /

Robertson, Anthony Lawrence. January 2009 (has links)
Thesis (M.S.)--Indiana University, 2009. / Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Jeffrey Wilson, Lenore Tedesco, Lin Li. Includes vita. Includes bibliographical references (leaves 92-95).
278

Evaluation of technology aimed to improve nitrogen use efficiency for delayed-flood rice (Oryza sativa L.) production

Satterfield, Jason Morris, January 2009 (has links)
Thesis (M.S.)--Mississippi State University. Department of Plant and Soil Sciences. / Title from title screen. Includes bibliographical references.
279

Single molecule switches and molecular self-assembly low temperature STM investigations and manipulations /

Iancu, Violeta. January 2006 (has links)
Thesis (Ph.D.)--Ohio University, August, 2006. / Title from PDF t.p. Includes bibliographical references.
280

Analysis of MODIS-Aqua imagery to determine spring phytoplankton phenology in the Strait of Georgia, Canada

Carswell, Tyson Kyle 21 December 2015 (has links)
The goal of this research was to construct a time series of accurate chlorophyll-a concentration for the Strait of Georgia (SoG), Canada, using an improved atmospheric correction scheme and workflow for the Moderate Resolution Imaging Spectroradiometer AQUA (MODIS) satellite instrument to describe the chla dynamics and spring bloom phenology in the SoG. In situ radiometric samples were acquired via Aerosol Robotic Network (AERONET), and hyperspectral data collected from a Hyperspectral Surface Acquisition System (HyperSAS) to assess three potential atmospheric correction schemes. Water property samples including total suspended material (TSM), chromophoric dissolved organic matter (CDOM), and chlorophyll concentrations (chla) were collected to further assess atmospheric corrections and the applied ‘Ocean Color 3 Modis’ (OC3M) standard chlorophyll algorithm. Regression, Absolute percentage difference (APD), Relative Percentage difference (RPD), and Root mean squared error (RMSE) analysis revealed the most appropriate method to be the ‘Management Unit of the North Seas Mathematical Models’ (MUMM) using the shortwave infrared spectrum (SWIR) to determine NIR-derived aerosol model. This method was used to construct a time series (July 2002-June 2014) of daily chlorophyll maps for all available imagery. Files were spatially binned into 8-day composites for the North and Central SoG where a modified threshold-based definition was used to determine the start of the spring phytoplankton bloom period, as well as timing of maxima and duration of the largest spring bloom. Results indicate Central SoG start dates range from late February to late April, with an average start date at the last week of March. These results compare favorably to Hindcast predictive modelling of bloom start dates. The Northern SoG bloom phenology starts on average 9 days earlier, and experiences lower chlorophyll-a magnitudes. Hierarchical clustering with correlation similarity of spring seasons indicate 2008 and 2007 were anomalous, while 2009 and 2012 were the most correlated for blooms occurring in the spring season. / Graduate / 0366 / 0416 / 0752 / 0368 / carswell@uvic.ca

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