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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.
691

Arbuscular mycorrhizal fungi enhance tolerance to bicarbonate in Rosa multiflora cv. burr

Cartmill, Andrew David 01 November 2005 (has links)
High bicarbonate (HCO3-) content and associated high pH of irrigation water is detrimental to plant growth. Sustain ableagricultural/horticultural production will increasingly have to rely on economically feasible and environmentally sound solutions to the problems associated with high levels of HCO3- in irrigation water. The ability of a mixed Glomus Tulasne & Tulasne species inoculum of arbuscular mycorrhizal fungi (AMF), Glomus ZAC-19 (containing Glomus albidum Walker & Rhodes, Glomus claroideum Schenck & Smith, and Glomus diaphanum Morton & Walker), to enhance plant tolerance to HCO3- was tested on the growth and nutrient uptake of Rosa multiflora Thunb. ex J. Murr. cv. Burr (rose). Arbuscular mycorrhizal colonized and non-inoculated (non-AMF) R. multiflora cv. Burr were treated with 0, 2.5, 5, and 10 mM HCO3-. Increasing HCO3- concentration and associated high pH reduced R. multiflora cv. Burr growth, nutrient uptake, and acid phosphatase activity (ACP), while increasing alkaline phosphatase activity (ALP). Inoculation with AMF enhanced plant tolerance to HCO3- as indicated by greater growth, nutrient uptake, leaf chlorophyll content, higher mycorrhizal inoculation effect (MIE), lower root iron reductase activity, and generally lower soluble and wall-bound ALP activity. While AMF colonization (arbuscules, vesicles, and hyphae formation) was reduced by increasing HCO3- concentration, colonization still occurred at high HCO3- concentration. At 2.5 mM HCO3-, AMF plant growth was comparable to plants at 0 mM HCO3-, further indicating the beneficial effect of AMF for alleviation of HCO3- plant stress.
692

Apply A Three-Dimensional Eco-Hydrodynamic Model To Study Eutrophication In Nanhua Reservoir

Su, Chih-yuan 06 August 2009 (has links)
Nahua reservoir is an important water resource for supplying drinking water to the Tainan area and a part of Kaohsiung in Taiwan. In recent years, Nanhua reservoir suffers eutrophication problems as many other reservoirs in Taiwan. In order to study eutrophication problems in reservoirs, a three-dimensional hydrodynamic and water quality model has been constructed using the FVCOM (Finite Volume Coastal Ocean Model) model to simulation the hydrodynamics, the nutrient dynamics and the phytoplankton growth in the Nanhua reservoir. The modeling of 3D hydrodynamics is the basic module dominating the circulation in the reservoir. The 3D eutro-dynamics are also calculated by the water quality module, which includes the dynamic variations of chlorophyll-a (Chl-a), dissolve oxygen (DO), carbon biological oxygen demand (CBOD), ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), organic nitrogen (ON), phosphate (PO4) and organic phosphorus (OP). The model was first calibrated with the data measured in 2007 and, then, verified with the 2008 data. The model results are in reasonable agreement with the field measurements, both in the calibration and the verification phases. The water level variations are influenced by daily supply for the drinking water treatment and the inflows from the catchment and from Chiashian aqueduct during the dry season in spring. Nutrients are mainly carried into the reservoir through these routes. The residence time in the reservoir and the phytoplankton response with the nutrient loads are calculated. The model results indicated that phytoplankton growth is limited by low temperature and long residence time during the winter. The chlorophyll levels are getting higher from spring through out summer, which is due to enough sun lights and high nutrient loads carried by the catchment runoff. Surface temperatures are higher then the bottom layers causing stratification that worsen the eutrophication problems. Besides the comparisons by hydrodynamic and water quality parameters, the Carlson Trophic State Index (CTSI) has been calculated to categorize the eutrophication levels in the reservoir, which have shown good agreement with the CTSI calculated from EPA sampling data. Therefore, the model can be used as a tool for water quality management in the Nanhua reservoir.
693

The potential impact of riparian buffer zones on sediment and phosphorus loading in two Canandaigua Lake subwatersheds /

George, Valerie. January 2009 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 2009. / Typescript. Includes bibliographical references (p. A-15-A-17).
694

Managing water utilities with geographic information systems the case of the city of Tampa, Florida : a thesis presented to the Department of Geology and Geography in candidacy for the degree of Master of Science /

January 2009 (has links)
Thesis (M.S.)--Northwest Missouri State University, 2009. / The full text of the thesis is included in the pdf file. Title from title screen of full text.pdf file (viewed on January 13, 2010) Includes bibliographical references.
695

Nutrient removal by algae grown in CO₂-enriched wastewater over a range of Nitrogen-to-Phosphorus ratios a master's thesis /

Fulton, Laura Michelle. Lundquist, Tryg J. January 1900 (has links)
Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on January 6, 2010. Major professor: Tryg Lundquist, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Civil and Environmental Engineering." "November 2009." Includes bibliographical references (p. 43-47).
696

Development of design basis for hydrodynamic vortex separators

Li, Yunjie. January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Civil and Environmental Engineering." Includes bibliographical references (p. 194-203).
697

Economic and environmental implications of a phosphorus standard : 160-sow representative farm in Montgomery County, Missouri /

Lansford, Vernon D., January 2001 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 152-159). Also available on the Internet.
698

Economic and environmental implications of a phosphorus standard 160-sow representative farm in Montgomery County, Missouri /

Lansford, Vernon D., January 2001 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 152-159). Also available on the Internet.
699

Characterizing storm water runoff from natural gas well sites in Denton County, Texas

Wachal, David J. Hudak, Paul F., January 2008 (has links)
Thesis (Ph. D.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.
700

Effects of intertidal oyster reefs on water quality in a tidal creek ecosystem /

Cressman, Kimberly A. January 2003 (has links) (PDF)
Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : 39-42).

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