Browsing by Subject "Water"
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Item Assessing the Effect of Pre-Oxidation at Different Stages of Water Treatment to Limit N-Nitrosodimethylamine (NDMA) Formation(2022-08) Noe, EricN-Nitrosodimethylamine (NDMA) is a disinfection by-product of emerging concern for drinking water utilities that use chloramines as a disinfectant. Identifying and eliminating the sources of NDMA precursors in watersheds may prove to be too difficult in most cases. Hence, pre-oxidation with ozone, ozone/hydrogen peroxide (so-called advanced oxidation), or free chlorine was explored for precursor destruction to limit subsequent NDMA formation following addition of chloramines.In this study, batch experiments were performed to investigate the effectiveness of pre-oxidation on precursor removal when applied at three stages in a drinking water treatment train: raw water (pH 7.9-8.4), lime-softened water (pH 10.6-10.8), and lime-softened water after re-carbonation (i.e., re-carb) to pH 8.6-8.9. NDMA precursor concentrations were assessed indirectly by quantifying NDMA formed after addition of preformed chloramines and incubating for three days at room temperature using the uniform formation conditions (UFC) protocol. Some water samples were spiked with ranitidine before pre-oxidation to add a well-known NDMA precursor compound to the otherwise unknown ambient precursor pool. Residual ozone and hydroxyl radical formation were monitored during the batch experiments. Total ozone exposure and subsequent hydroxyl radical exposure from ozone decay increased with increasing ozone dose. Ambient NDMA precursor concentrations (NDMAUFC) in the raw water ranged from 8 to 10 ng/L and increased to 13 to 26 ng/L after lime softening. In general, pre-oxidation via ozone, advanced oxidation, and free chlorine effectively limited NDMA formation to ≤ 5 ng/L for both winter and summer water quality conditions. The temperature at which pre-oxidation occurred had little effect on precursor destruction for a given ozone dose. Pre-oxidation with ozone also was able to significantly decrease NDMAUFC for water samples spiked with 500 ng/L ranitidine, from 350 ng/L of NDMAUFC before pre-oxidation to 21 ng/L for an ozone dose of 1 mg/L, with further decreases with increasing ozone dose. This study provides critical information on NDMA precursor destruction via pre-oxidation with three common oxidants over a range of water quality conditions (i.e., pH and temperature).Item Assessment of the Impacts of Various Grazing Management Strategies on Southern Minnesota Stream Channels(2018-05) Kim, SeongjunStream riparian corridors are inherent to many farms in southern Minnesota. They are complex and diverse ecosystems, provide transportation for drainage from agricultural fields, and contribute to the quality of the larger watershed to which they belong. However, much of the 3.5 million miles of rivers in the United States are impacted, with sedimentation and excess nutrients being the most significant causes of degradation. The agricultural areas of southern Minnesota commonly use stream corridors as pasture since they are generally unsuitable for crops and provide a natural source of water for livestock. Traditional methods of grazing livestock can cause reduced vegetative cover, compacted soils, water contamination, sedimentation, and eroded banks. Managing livestock by limiting the location and duration of their grazing has seen some success in reducing the impact compared to conventional grazing methods. My research aims to further determine the impacts various grazing management strategies have had on streams. Geomorphic data from four sites across three streams are analyzed to evaluate effects of current grazing strategies and changes in grazing strategies. Grassed and wooded areas are also compared, as grazing directly influences the vegetative communities. The results suggest that both managed and grazing exclusion sites showed healthier channels than conventional grazing sites did, and that grassed bank areas contribute more to channel stability than wooded bank areas. In certain situations, managed grazing has the potential to be more beneficial to stream channel health than the prohibition of grazing.Item Biuret hydrolase and cyanuric acid hydrolase: enzymes for metabolism and detection of s-Triazines(2013-08) Cameron, Stephan MaryThere is an increasing need to test for chemicals present in adulterated foods or food products. There is also an increasing need to degrade chemicals present in water. The s-triazine compounds compose a major class of industrial chemicals. The research in our labs focuses on developing microbial enzyme-based bioassays for s-triazines and understanding the enzymatic biodegradation of them. Cyanuric acid is an intermediate in bacterial metabolism of common s-triazine compounds. In 2008, intentional adulteration of milk and milk products (e.g., infant formula) with the s-triazine melamine affected 300,000 infants & youth in China, resulting in 50,000 hospitalizations and 6 deaths. In 2010, tons of melamine-tainted milk products were again for sale. Melamine is sometimes co-contaminated with cyanuric acid. When ingested together, they form insoluble crystals in kidneys, which may lead to renal failure. This scenario caused >13,000 pet deaths in the U.S. (2007) due to adulterated pet food. There is interest in detecting cyanuric acid and melamine, individually or together, in foods. With regards to s-triazines in water, cyanuric acid is a stable compound that accumulates over time in swimming pools disinfected with N-chloroisocyanuric acids. With high concentrations of cyanuric acid, disinfection is ineffective and public health is not protected from disease-causing microorganisms. To address this concern, the pool is drained, refilled with fresh water, and treated again.The research here identifies and characterizes microbial enzymes involved in s-triazine metabolism that could be used to 1) develop sensitive bioassays for cyanuric acid and/or 2) biodegrade cyanuric acid in water. Cyanuric acid hydrolase acts on cyanuric acid. Using 13C nuclear magnetic resonance (NMR) and mass spectrometry (MS), this research establishes the product of this reaction is carboxybiuret. This work also demonstrates carboxybiuret spontaneously decarboxylates to generate biuret. In the subsequent reaction, biuret hydrolase acts on biuret. Using an interdisciplinary approach combining bioinformatics, microbiology, molecular biology, protein separations, enzymology, quantitative analyses, 13C NMR, and MS, this research identifies and characterizes the first biuret hydrolase to be purified in active form (from R. leguminosarum bv. viciae 3841). Together, cyanuric acid and biuret hydrolases release ammonia, which is detected via the colorimetric Berthelot Assay. Cyanuric acid hydrolase belongs to rare family of unstable proteins. In an effort to identify a stable protein scaffold that could be modified to hydrolyze cyanuric acid, an array of amidohydrolase family members were analyzed for low-level activity with cyanuric acid to use as a starting point. Guanine deaminase from Bradyrhizobium diazoefficiens USDA110 was observed to have such activity. This is the only known metallo-enzyme to hydrolyze a ring-opening amide bond of cyanuric acid.Item City of Forest Lake Sustainability Action Plan(Minneapolis: Center for Urban and Regional Affairs, 2008) Breakiron-Aultman, Sara; Birkeland, Brant; Vardhan Das, Kirti; Flannerty, Sean; Meyer, Kate; Quinn, JulieItem Comparison of Biofiltration Media in Treating Industrial Stormwater Runoff(2019-07) Isaacson, KristoferBiofiltration systems have become one of the most commonly used best management practices in dealing with stormwater runoff. Stormwater runoff is inherently variable, with the contaminants present depending greatly on the land use of the catchment basin. This study characterized the stormwater collected from an industrial site in northeastern Minnesota. It was determined the pollutants of concern for this site are dissolved heavy metals (Aluminum, Copper, Iron) and bacteria. Different media exhibit different strengths and weaknesses in the removal of pollutants in these biofiltration systems. As a result, there is not a universal combination of media that can adequately treat all stormwater. 18 bio-based media were tested in batch experiments to determine if they possessed any capacity for heavy metal removal. Eight media (APTsorb, bioAPT, biochar, marble, sand, vermiculite, and zeolite) that showed good removal were studied further in downward flowing column experiments. These column experiments determined that all materials demonstrated some capacity for dissolved metal removal with the exception of sand. However, marble performed the best by a significant margin, removing over 10 mg/cm3 of iron, 4 mg/cm3 of aluminum, and 2 mg/cm3 of copper. The four materials that were determined to have the largest removal capacity for heavy metals (APTsorb, compost, marble, zeolite) were tested in an additional column experiment in which the synthetic stormwater was inoculated with E. coli. Marble again performed the best removing 100% of E. coli throughout the duration of a 56-hour continuous flow column experiment. This characterization process provides valuable information on the effectivity and longevity of a variety of media in the design of future biofiltration systems.Item Comparison of Evapotranspiration Estimation Methods and Implications for Water Balance Model Parameterization in the Midwestern United States(2019-12) Talbot, MichaelEvapotranspiration is the second most dominant component of the global water cycle behind precipitation, yet it remains one of the most difficult to measure and model. The numerous methods that have been developed for estimating evapotranspiration (ET) rates using climatological data vary in both complexity and spatiotemporal robustness. While the Penman-Monteith method has continually been shown to compare better with observed ET rates across more geographies and timescales than any other method, its high data requirements remain a barrier to use in many areas, and it is often desirable or necessary to make use of an alternative method. Daily reference ET estimates from the Penman-Monteith method were compared to ET estimates from seven alternative methods, which were generated using 14 years of observed weather records at five locations across the Midwestern United States. Then, a one-dimensional water balance model, DRAINMOD, was run at 362 locations across the Midwest using 50 years of synthetic climate data and three distinct sets ET inputs: 1) reference ET from the Penman-Monteith method, 2) potential ET generated from the Penman-Monteith reference ET and location-specific crop coefficient curves, and 3) potential ET from the Thornthwaite method. Results suggest that the best alternative method to Penman-Monteith varies by location, application, and timescale of interest, and that the misapplication of ET estimates for water balance model parameterization could have a dramatic impact on the accuracy of model predictions.Item Constructed wetland used to treat nitrate pollution generated from agricultural tile drainage waters in Southern Minnesota(2014-09) Ross, Nikol BaileyNitrate molecules are highly soluble in water and are bioavailable to plants. These properties are why excess nitrates in water are one of the main causes of hypoxia in the northern Gulf of Mexico. Over 90% of these nitrates originate from non-point sources such as agricultural fields. In fields with tile drainage systems nitrates have a swift passageway from field to surface waters. This study focuses on one Midwestern farm field located in southern Minnesota, along Elm Creek, a Blue Earth tributary. Tile drainage water from this field discharges into Elm Creek at a concentration averaging 23.0 mg/L NO3 as NO3-N. During the spring of 2013 a three celled treatment wetland was constructed adjacent to Elm Creek. The tile drainage system was re-routed to discharge into the constructed wetland. In the 2013 field season water volumes were monitored continuously and water samples were taken from the inlet, the wetland cells, and the outlet on a periodic basis. During the season the volume of tile drainage water that reached Elm Creek as surface water was reduced by 82%. The concentration of NO3-N in the water was not significantly reduced. However, the total load of NO3-N that reached Elm Creek as surface water was reduced by 262 to 332 pounds (14.4-18.2 lbs./acre). Most of the water that did not reach Elm Creek infiltrated into the subsurface soils and still contained NO3-N. Using the MPCA's (2013) estimates of groundwater denitrification for agroecoregions, a 45% reduction rate was applied at this location. When the 45% reduction rate is applied to the subsurface load it is estimated that 113.0 to 134 lbs. (6.21-7.36 lbs./acre) of NO3-N were removed from the infiltrated water. Thus a total of 124 to 172 lbs. (6.81-9.45 lbs./acre) of NO3-N were removed from the entire wetland system which accounts for 37.1-43.3% of the NO3-N.A concurrent laboratory experiment was set up in 2013 to test the effectiveness of different soils and vegetation at removing nitrate loads. Wetland mesocosm experiments were set up with soil collected from the field site and the design vegetation used in the field cells. Three vegetated mesocosm tanks were planted in Coland soils with Switchgrass (Panicum virgatum), Fringed Sedge (Carex crinita) and a tank with an equal mix of Dark Green Bulrush (Scirpus atrovirens), Panicum virgatum, and Carex crinita. The results showed that the mixed vegetation regime and the Panicum virgatum had significantly greater nitrate removal than the control (Coland bare soil). The mixed vegetation mesocosm had the highest amount of nitrate removal after 10 days at 34.9%. There was no significant difference in the nitrate removal rates in the soils tested.Item Encapsulation of proteins and cells in silica nanoporous materials(2011-11) Reategui, EduardoMy dissertation presents fundamental and practical scientific contributions. I demonstrated the versatility of the sol-gel processing technology for the study of the basic science behind water and protein structure under confinement, and for the development of novel biotechnology and biomedical engineering applications based on cell encapsulation in nanoporous silica gels.For the basic science studies of my dissertation, silica nanoporous gels were used to investigate the kinetic and thermodynamic transitions of water under confinement. I demonstrated a direct correlation between the structure of confined water and the secondary structure of proteins in a wide range of temperatures (- 196C to 95C). I showed qualitatively that the incorporation of a highly hydrogen bonding osmolyte contributed to improve the thermal stability of encapsulated proteins by a mechanism based on prevention of adsorption at the surface of the nanoporous silica material. For the practical contributions of my dissertation, I developed two novel applications relevant to the biotechnology and biomedical engineering fields. These applications were based on the encapsulation of prokaryotic and eukaryotic cells in silica nanoporous gels. First, I developed a highly selective and efficient biodegradation platform for the removal of an herbicide, atrazine, from contaminated water. In the second application, I invented a cell capture and isolation methodology that was successfully tested as a cancer cell isolation tool from mixed populations of eukaryotic cells (normal and cancer cells). Miscellaneous applications were also investigated such as encapsulation as a means of cryopreservation of mammalian and algae cells, and were incorporated in the Appendices of this thesis.Item Examining Collective-Efficacy As A Framework For Watershed Scale Resource Management(2017-10) Perry, VanessaThis dissertation explores a collective-efficacy theoretical framework as it relates to climate change and extreme weather response and water and stormwater management in a northern Minnesota coastal community. A multi method research approach was implemented in two sub-watersheds of the Lower St. Louis River Basin near Duluth, Minnesota that included 27 interviews, two focus groups, a workshop, and bio-physical modeling of potential climate impacts. Perceived collective-efficacy to make decisions and take action to manage natural resources and potential future resource impacts from climate and extreme weather impacts emerged as a prominent theme in analysis. This dissertation explores collective-efficacy in the study community through three approaches, 1) perceived collective-efficacy for resource management and climate and extreme weather response as it relates to relationship to place, 2) the use of a collective-efficacy framework throughout a sequential community-based, multi methods, natural resource management study, and 3) the application of collective-efficacy principals in an applied tool for use in local decision making. An exploration of collective-efficacy in local communities can help identify barriers to effective decision making and opportunities for progress in climate and extreme weather preparedness. This work both builds the body of literature on climate response related collective-efficacy research and offers an applied path for stakeholders working collectively to address challenging natural resource management issues.Item Fluid Landscapes: Materializing the Future on Thailand's Flooded Rivers(2018-11) Moberg, LaurieIn 2011 rivers in Thailand demonstrated their irrepressibility in unprecedented flooding. The Thai state responded to the dramatic floods with a comprehensive water management plan including 21 new dams on upland tributaries, which in turn mobilized anti-dam protest campaigns across Northern Thailand. The material upheaval became the catalyst for my research as it disrupted normative hydrosocial relations and drew water into political debate and social contestation over the future of Thailand’s waterscapes. Based on 15 months of ethnographic research with three rivers and three river communities in the critical post-flood period, this dissertation examines how rivers in Thailand become politically active in the tense, fragmentary work of world-making, in claims of indigeneity, in protests against development agendas, and in the negotiation of disasters. To do this, I approach rivers as water-beings with creative and diffuse capacities to co-constitute the world and create political and cosmopolitical effects. I trace the entanglements between people and water, human beings and water-beings, across varied geographies, histories, and socioecologies to demonstrate how these multimaterial, multispecies assemblages produce overlapping and contradictory realities. I argue that the social, material, and discursive transformations in the aftermath of disasters compel us to reevaluate how we understand nature and renegotiate how we make political and ecological claims with it.Item Geological Crisis in Yemen: The Politics of Resource Scarcity(2013-10-01) Qamar, AsfandiyarYemen's oil and water crisis has been a powerful agent of change in Yemeni society, affects of which are transforming Yemen's political, economic and social spheres. Yemen is far from the only country in the region currently experiencing or expected to encounter political, social and economic turmoil as a result of acute water and oil scarcity. As a vital ally of the U.S. and Saudi Arabia in counter-terrorism, Yemen also holds strategic importance for both countries who would like to see it a more stable country. Decades of relying entirely on Yemen's modest oil exports to operate complex system of patronage towards its various tribes and bureaucrats, operated largely in secrecy, also encouraged widespread mismanagement, abuse and corruption. As a result not only did the oil reserves and revenues from it began to declined drastically as oil ran out, a culture of crises mismanagement and corruption also depleted contributed to the depletion of Yemen's water supply. Therefore, Yemenis today face 40% unemployment, combined with acute water and oil shortages leading to crises in the agricultural sector, widespread poverty and malnourishment. Furthermore, consistent lack of effective action from the government of former President Ali Abdullah Saleh not only destroyed his legitimacy, but also eventually uprooted the system of patronage that he relied on to govern the country. The current political transformation and National Dialogue underway in Yemen will have to negotiate a new social contract and a viable political system that can revive Yemen's economy and effectively deal with its considerable security problems.Item Graphene Sensors and Perovskite Solar Cells for Water Detection(2020-08) Kim, JungyoonWater quality test is the first step for cleaning water which is a fundamental element for human health and the environment. The objective of this research is to develop very small, cheap, fast, accurate sensors to detect pollutants including phosphate, nitrate, mercury, and chloride in waters. This is a new testing and analysis technique, which can provide accurate sensing capability to assess the cleanness of waters at a very low cost. The proposed new technology is to manufacture graphene based sensors using the micro-manufacturing. Graphene is a monolayer of carbon atoms with outstanding electrical properties well studied material for a decade by many research groups. Since graphene sensitively responds to molecules in liquids, this property will enable the tiny sensors to detect pollutants in water with very high sensitivity and super short response time to pollutants. Even though graphene responds to the surroundings, it does not have the selectivity to the specific target. In this research, the selective membranes are synthesized and applied to the graphene based sensors to detect the target ions such as nitrate, phosphate, chloride, and mercury. The selective membranes are prepared with two different key materials including molecular imprinted polymer and ionophore. The sensor is characterized by a semiconductor analyzer, and the sensors are tested with several ion solutions to verify their selectivity. The detection limits of the sensor are 0.82, 0.26, 0.87 mg/L and 1.125 µg/L for nitrate, phosphate, chloride and mercury, selectively. In addition, the detection limit of nitrate is enhanced to 0.32 mg/L using the AAO substrate. Here, this research also includes developing perovskite solar cells as the power source of the sensors. Since solar energy is clean and independent, it is one of the important renewable energy resources. Silicon solar cells have already been commercialized and used to generate electricity in various fields because solar cells can directly generate electricity from photons, and they do not cause a problem to our environment as well. Among several types of solar cells, the perovskite solar cells have been studied by many research groups owing to low-cost fabrication, low fabrication temperature and high efficiency. This research includes the preparation of the materials and fabrication of flexible perovskite solar cells. We also characterize the surface morphology of the perovskite to check the grain size by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The efficiency of solar cells is measured by the solar simulator. We study the relationship between the grain size and the CVD process time and successfully demonstrate the performance of devices. The flexible solar cells show the power conversion efficiency of 7.6 % under the AM 1.5 G. As extended research, we have tried to find the proper hole transport layer (HTL) for the device and applied two HTLs, including PEDOT:PSS and PTAA to the devices.Item Hygroscopicity of pharmaceutical crystals.(2009-01) Chen, DabingThe active pharmaceutical ingredients (APIs) as well as excipients in a solid dosage form can take up water vapor both during manufacture and subsequent storage of the product. Uptake of unacceptable amount of water can cause adverse effects on physical and chemical stability of APIs and functionality of excipients. It is prudent to select drug candidates with low hygroscopicity to minimize the development risk and time. The objectives of this study are: (i) to investigate the risk in predicting long-term water uptake from short-term water sorption studies, (ii) to understand the thermodynamic and kinetic factors that affect water uptake by pharmaceutical crystals. Automated sorption microbalance (ASM) is often used to determine the hygroscopicity, in which the small sample size and gas purge are believed to accelerate the water sorption process so that equilibrium could be attained in a short time period. However, caution must be exercised when the rates of water vapor diffusion or heat transfer at the solid-vapor interface are not the limiting factors. Four cases are discussed in this thesis, in which ASM failed to predict long-term water uptake. 1) Water vapor was believed to diffuse into the lattice of a metastable crystalline form and induced a polymorphic transformation. The crystallization of the stable form led to a decrease in water content. 2) Adsorbed water formed a surface solution and enhanced the mobility of surface molecules. Nucleation rate of hydrate could be the rate-limiting step. 3) Water sorption induced a crystal to liquid crystal transformation in a surface-active compound, where the latter retains orientational but lacks positional order of molecular packing. 4) The formation of a metastable liquid crystalline phase was kinetically favored for amorphous materials formed in surface-active compounds. The metastable liquid crystalline phase was stable for 3 months when stored under ambient conditions.Item Investigation of Domestic Water Consumption in the Sports and Health Center at the University of Minnesota-Duluth(2010) Li, Jie; Schiff, Jessica; Brengman, SarahThe study aims to develop and conduct an investigation of the total domestic water consumption in the Sports and Health Center (SpHC) on the University of Minnesota-Duluth (UMD) campus. The investigation methods include collecting data from internal and external resources via interview, photography and internet-based research. Researchers will analyze data that reflects the current water consumption in SpHC and provide potential solutions to responsibly and sustainably consume water.Item Land use/land cover and hydrologic effects on North Shore tributary water quality(2013-08) Crouse, Andrea BerniceAlthough they are inextricably linked, the impact of meteorological events and climate variations on water quality have not yet been fully explored. Streams considered for this study are facing increased developmental pressures and have, thus far, remained relatively pristine, although some are already listed as "Impaired". Through use of accumulated water quality data for Duluth and North Shore (Minnesota, USA) streams and GIS analysis of watershed characteristics, empirical models which explain the variability of water quality data, stratified by hydrologic regime, and mediated by landscape characteristics were analyzed. Multivariate statistical found correlations between measures of particulate-related and soluble water quality: sorted by hydrologic regime (i.e. snowmelt, storm events and baseflow); and mediated by landscape metrics. Measures of development at the local scale, including % impervious, were shown to be significantly correlated with increased particulate-related water quality metrics during high flow periods. Wetland cover at the whole watershed scale was negatively correlated with particulate-related water quality metrics, though at the local scale wetlands were positively correlated with soluble water quality metrics. Relationships between water quality metrics and measures of forest cover and stand type were shown to be strongly influenced by the scale at which analyses were performed. Regression analyses indicated that local land use/land cover (LULC) metrics best predicted particulate-related and soluble water quality metrics during high flow periods. During baseflow periods, whole watershed LULC metrics were the best predictors of particulate-related water quality metrics. Results suggested that road salt applied during the winter months may be stored in the soils or groundwater and released into urban trout streams during rain periods. The soluble water quality parameters were less clearly linked to just a few LULC characteristics and a there was no clear pattern for differences between whole vs. local watershed analysis. Soluble nutrients also exhibited seasonal variability. These analyses are an important step towards improving watershed planning and management policies by providing a tool for forecasting the impacts of land use decisions on water quality with known accuracy.Item Landscape effects on stream temperature in Minnesota Streams of the Lake Superior Basin(2014-05) Black, Brian JimChanges in land use and land cover are known to be important factors causing thermal alterations in small streams. The heating of coldwater and coolwater streams influences aquatic communities that inhabit such environments. We recorded continuous stream temperature data at 50 sites during July - September of 2008 to better understand thermal controls on small streams (1st - 3rd order) within Minnesota's Lake Superior watershed, with specific interest in determining the role of water storage capacity and impervious surface cover. Local and landscape variables were used to predict in-stream temperature using multiple regression analyses. These analyses identify those variables most correlated with stream temperature, and therefore, most likely to influence thermal characteristics. Sites were selected to represent natural gradients of water storage capacity (0-86%) and impervious surface cover (0-26%) within each catchment. Stream habitat data were collected to explain natural temperature variation among sites due to local conditions. Results indicate that geomorphic (stream width and depth), atmospheric (air temperature), and local landscape (riparian shading) variables are all strongly correlated with stream temperature. Thermal characteristics are also influenced by regional landscape variables such as hydraulic conductivity and percent land cover classified as open water or emergent herbaceous wetlands. In contrast, neither impervious surface cover nor water storage capacity were good predictors of the stream temperature metrics summarized in this study. Land cover variables were selected more frequently in best-fit models when they were weighted by distance from the sampling location, indicating that position in the watershed may be an important factor. These trends suggest that changes in land use and land cover have great potential to either mitigate or exacerbate the impacts on stream temperature from climate change, and stress the importance of effective land management.Item Mantle dynamics, composition, and state in regions associated with active and ancient subduction.(2008-05) Courtier, Anna MahrAbstract not available.Item Minnesota Phosphorus Loss: How Soil Loss Is Only Part of the Story and Why Modeling Can Be Improved by Considering Subsurface Phosphorus Loss(2021-05) Reitmeier, HeidiThis study explores 20 years of Minnesota regional phosphorus (P) management data across agricultural landscapes and how these are modeled by the Minnesota Phosphorus Index (MNPI). Nutrient-loading and farm management records from 1999-2019 were compiled across 17 different Minnesota counties representing 5 different state regions, including sites from Discovery Farms of Minnesota, Minnesota Department of Agriculture, Minnesota Agricultural Water Resource Center, and the University of Minnesota. The consolidated data cover two critical watersheds in nutrient management, one flowing north to Canada's Lake Winnipeg, the other flowing south through the Mississippi River ultimately to the Gulf of Mexico. Best management practices are needed for P loss within these watershed basins due to rising concerns about recurrent algal blooms in both watersheds. This study combines historical nutrient-loading data and farm management data to see how soil loss due to erosion impacts P losses and how the MNPI models P-loss risk.Item Momentum - Fall 2011(2011) University of Minnesota: Institute on the Environment