Browsing by Subject "Wild rice"

Now showing 1 - 11 of 11
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    Biogeochemical Interactions And Ecological Consequences Of Sulfur In Stands Of Wild Rice
    (2020-05) LaFond-Hudson, Sophia
    Wild rice is an ecologically and culturally important plant that typically grows in lakes and rivers in Minnesota that have low sulfate concentrations. Previous work demonstrated that elevated sulfate concentrations contribute to the decline in wild rice populations when conditions allow for the reaction of sulfate to sulfide. This dissertation investigates the fate of sulfate in the rooting zone of wild rice, mechanisms and consequences of sulfide exposure to plants, and the long-term effects of sulfide exposure on population dynamics. Key findings include 1) iron plaques on root surfaces transition from iron oxide to iron sulfide during reproduction if sulfate is elevated; 2) in elevated sulfate, seed production is delayed and shortened and plants produce fewer, smaller seeds with less nitrogen; and 3) populations of wild rice grown in low sulfate have stable biomass oscillations with a period of approximately 4 years, but elevated sulfate destabilizes these cycles and drives the population toward extinction.
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    Contesting risk: science, governance and the future of plant genetic engineering
    (2014-10) Kokotovich, Adam Eli
    As a process to synthesize science and characterize potential ecological risks to inform decision making, ecological risk assessment (ERA) influences how the potential for harm is studied and is foundational to national and international decision making on genetically modified organisms and other technologies. Existing literature has argued that ERA is built on values-based judgments that should be subject to critical scrutiny, and that conflicts about risk are influenced by competing understandings of what constitutes ecological harm, beneficial technology, desirable scientific research. However, there has been a lack of empirical work that explores the implications of these insights. As a contribution to this work, I use interviews, document analysis and participant observation to explore three case studies involving plant genetic engineering and the contestation of risk. The first case study examines the differences between two competing ERA guidelines for assessing the impacts of genetically modified plants on non-target organisms. Findings include that the guidelines proposed consequentially different processes for the study of potential risks as a result of divergent judgments about hazard identification, substantial equivalence, species selection, and indirect effects. The second case study explores how expert stakeholders envision future environmental regulation for plants produced by novel, targeted genetic modification techniques. Their views varied based on different underlying assumptions associated with what constitutes environmental risk and the adequacy of existing regulations. For the third case study, I participated in and studied a collaborative committee that, in response to issues concerning wild rice and the potential for its genetic engineering, is engaged in an anticipatory process to influence scientific research policy at the University of Minnesota. I found that the committee pursued the inclusion of Native American worldviews into wild rice scientific research by using a conceptual framework of "bridging worldviews" that made explicit how wild rice research is based upon contestable assumptions about risk, science, and the desired state of the environment. Across three diverse case studies, this research demonstrates the importance of interrogating the values-based judgments and assumptions that underlie ERA and decision making processes for genetically modified plants and environmental issues more broadly.
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    Crayfish and Baitfish Culture in Wild Rice Paddies
    (University of Minnesota Duluth, 1995-09) Richards, Carl; Gunderson, Jeffrey; Tucker, Paul; McDonald, Michael E
    The objectives of the report are to identify the influence of time of capture, crayfish size, sex, and eyestalk ablation on soft shell crayfish production; to examine crayfish harvest in production-sized wild rice paddies under simulated commercial harvesting; to examine the influence of crayfish densities on wild rice depredation; to asses sucker production potential in wild rice paddies; to assess the potential of aeration for influencing the growth and survival of baitfish and crayfish in wild rice paddies; to assess the commercial viability of softshell crayfish production; to transfer results of this research to potential entrepreneurs, fish farmers, and other interested persons,
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    Effect of cereal grains on the formation of heterocyclic aromatic amines in fried beef patties
    (2012-08) Kyllo, Rachel Renae
    The effect of incorporating flours representing different anatomical parts of the grain of corn, wild rice, and oat as well as corn bran extract into beef patties on the formation of heterocyclic aromatic amines (HAAs) during grilling was investigated. Beef burgers containing 5 or 10% dry cereal solids or cereal extract adsorbed to a cellulose carrier were grilled for 7 minutes per side on an electric grill. The HAA content of the cooked material was assessed using an optimized solid-phase extraction method, reversed-phase HPLC separation, and UV and fluorescence detection. 9H-Pyrido[3,4-b]indole (norharman), 1-methyl-9H-pyrido[3,4-b]indole (harman), 9H-pyrido[2,3-b]indol-2-amine (A-alpha-C), 1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridin-2-amine (PhIP), and 3,8-dimethyl-3H-imidazo[4,5-f]quinoxalin-2-amine (MeIQx) were detected in all burgers. Norharman and harman formation were significantly increased in fried beef patties grilled with wild rice hulls, wild rice flour, and oat hulls. Other treatments also tended to increase beta-carboline (harman and norharman) and PhIP levels relative to plain beef patties. Due to the analytical set-up it was not possible to obtain a full set of reliable data about the effect of cereal materials on the formation of MeIQx, but some materials may be able to reduce the formation of this HAA. It is concluded that the addition of whole cereal materials in beef patties is not an effective way to reduce the formation of beta-carbolines and PhIP during grilling. Definite conclusions about the effect of cereal materials on the formation of MeIQx and structurally related HAAs cannot be drawn from this study.
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    Iron and Sulfur Cycling in the Rhizosphere of Wild Rice (Zizania palustris)
    (2016-08) LaFond-Hudson, Sophia
    Wild rice (Zizania palustris), an annual macrophyte with significant cultural, economic, and ecological value, grown in high sulfate develops black iron sulfide precipitates on root surfaces, and produces fewer and lighter seeds, leading to decreased populations long-term. To investigate the role of iron sulfide precipitates in impaired seed production, wild rice plants grown in buckets were exposed to 300 mg/L of sulfate, and harvested biweekly for extraction of root acid volatile sulfide (AVS) and weak acid extractable iron and analysis of plant and seed N. In sulfate-amended plants, root AVS accumulated rapidly just prior to seed production. Simultaneously, iron speciation of the root precipitate shifted from Fe(III) to Fe(II), consistent with a transition from iron (hydr)oxide to iron sulfide. Sulfate-amended plants produced fewer, lighter seeds with less nitrogen. It is suggested that sulfide inhibits N uptake, causing rapid AVS accumulation during the reproductive life stage to disproportionately harm seed production.
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    Manoomin (wild rice) and environmental change at a significant river system of the Lac du Flambeau Band of Lake Superior Chippewa
    (2021-01) Waheed, Alexander
    Wild rice, an annual aquatic grass that grows across the Great Lakes region, has dietary, cultural, medicinal, and spiritual significance to the sovereign Tribes of the region, but its abundance has been declining despite its legal protection under treaties. While certain factors (both environmental and societal) have been demonstrated to impact wild rice health and growth, there is no single answer to explain this broad regional loss. Ongoing work between researchers at the University of Minnesota and tribal partners - including natural resource stewards, Tribal leaders, elders, rice chiefs, and community members - has yielded a multidimensional approach that seeks to capture the various forces influencing wild rice. The collaborative emphasis has been an integral part of the methods, and a significant result in its own right. In this study, hydrologic, geochemical, nutrient, sediment, and vegetation parameters are assessed to examine their impact on the growth of wild rice at two riverine subsites on the Lac du Flambeau reservation in northern Wisconsin: one subsite with abundant wild rice and a second subsite with sparse wild rice. To broaden the inferences that could be made from this localized, intensive study, a large statewide dataset from a previous study by Myrbo et al. (2017a) was reanalyzed to develop multiple lines of evidence for the influence of these factors. Based on this multidimensional approach, the emerging data and observations suggest highly flocculent sediments and related nutrient deficiencies may be driving forces behind the loss of wild rice in this study system and have implications for wild rice health in the wider region.
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    Supporting data for "Sulfur geochemistry impacts population oscillations of wild rice (Zizania palustris)"
    (2020-07-10) LaFond-Hudson, Sophia; Johnson, Nathan W; Pastor, John; Dewey, Brad; lafo0062@d.umn.edu; LaFond-Hudson, Sophia
    Wild rice populations decline with exposure to elevated sulfate due to production of sulfide in anoxic sediment. Using self-sustaining wild rice mesocosms, we collected data on the population response to sulfate, as well as iron and litter, which both may modify the production and availability of sulfide to plants. Wild rice also experiences natural population oscillations due to delays in release of nitrogen from decomposing litter. We use this data to investigate how sulfate-induced population declines interact with stable litter-driven population cycles. Population data was collected 2014-2019, and geochemical data (iron, sulfide, pH) was collected in 2019, after 5 years of of a factorial design treatment (sulfate, iron, litter).
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    Temperature dependent sulfate transport in aquatic sediments
    (2014-11) DeRocher, Will D.
    Sulfate, released to overlying waters from natural sources and human activity, has the potential to be reduced to sulfide within the anoxic environments of aquatic sediments and negatively impact the growth of aquatic vegetation. Wild Rice is of particular concern within Minnesota as it is both an economic and cultural resource within the state. This study was conducted to characterize the temperature dependence of sulfate transport, via diffusion, between overlying waters and sediment porewaters through the use of laboratory experimentation and mathematical analysis to study the transient response to changes in the overlying water concentration. Two riverine sediments with contrasting organic carbon content from the St. Louis River watershed in northern Minnesota were characterized for their bulk geochemistry and incubated under laboratory conditions to observe the temperature dependence of ion transport between overlying water and sediment porewaters. Two identical sets of laboratory microcosms, incubated under warm and cold conditions, were subjected to a sulfate loading phase in which the overlying water was spiked with sodium sulfate to induce a concentration gradient between the sediment porewaters and overlying water. At the end of the sulfate loading phase, the sulfate gradient was reversed by replacing the overlying water with fresh water, causing sulfate to diffuse out of the sediment, back into the overlying water. During the sulfate recovery phase, sodium bromide was spiked into the overlying water. Bromide, acting as an inert chemical tracer, provided a diffusion-only baseline with which to compare to reactive sulfate. The anion concentrations in the overlying waters were closely monitored to quantify changes in the concentration through the sulfate loading and recovery phases. Non-destructive porewater samples were collected using Rhizon® soil moisture samplers to measure concentrations of sulfate, bromide, ferrous iron, pH, and sulfide at discrete depths in the sediment during key times after changes in surface boundary conditions.Averaged results from both the high and low organic sediments showed sulfate transport occurred 49% faster out of the overlying waters into the sediments at 23°C when compared to 4.5°C. Estimated rates of sulfate reduction at 4.5°C were on average, 40% of those estimated at 23° C. After seven weeks of recovery from the sulfate loading, porewater sulfate concentrations in the warm microcosms had dropped back to ambient levels while slightly elevated sulfate levels were still noticed within the cold microcosm porewater. Even though more sulfate diffused into the warm sediments, the cold sediments retained the sulfate for a significantly longer period of time after the change in boundary layer conditions due to the retarded rates of diffusion and reaction. The longer the sediment is exposed to elevated sulfate levels a greater potential exists for the wild rice seed within the sediment to be exposed to sulfide.
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    Wild rice geochemistry and reproductive life stage data from experimental pots amended with sulfate, 2016
    (2019-10-24) LaFond-Hudson, Sophia L; Johnson, Nathan W; Pastor, John; Dewey, Brad; lafo0062@d.umn.edu; LaFond-Hudson, Sophia L
    Wild rice, an annual aquatic plant produces fewer, smaller seeds with less nitrogen when exposed to sulfide, but does not produce decreased vegetative biomass. We compared the timing and duration of reproductive life stages in sulfate-amended plants to unamended plants to see how sulfide affects reproductive phenology. We recorded the life stage of plants starting with initiation of reproduction until senescence and measured seed count, mass and nitrogen content. Additionally, we sampled the geochemistry of porewater, sediment, and root surfaces to understand how plant life stage may control sediment redox conditions relevant to sulfide.
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    Wild rice: The dynamics of its population cycles and the debate over its control at the Minnesota legislature.
    (2008-07) Durkee Walker, Rachel Elena
    Population cycling in plant and animal communities is of interest to Ojibwe band members and ecologists, and Western ecologists. The causes and consequences of wild rice population cycling and its long term viability have both cultural and scientific implications. I examine several Western scholars' research, its strengths and weaknesses, regarding Ojibwe accommodation of wild rice populations. Building on the interest of Ojibwe and Western ecologists in population cycles, and collaborating with Fond du Lac Reservation managers, I present a model which simulates delays from the release of nitrogen in decomposing wild rice straw. The model and experimental work show how these delays may cause population cycles. I planted wild rice seed obtained from the Fond du Lac Reservation over three years in mesocosms. I asked whether wild rice litter accumulation could inhibit plant growth by nitrogen immobilization in fresh litter. The timing of litter nitrogen immobilization and mineralization affected the potential growth of wild rice, seed production and total plant nitrogen. My data reveals that delays in nutrient availability due to deposition of immobilizing litter potentially cause fluctuations. Litter quantity appears to play a central role. Root litter also appears to be the source of the longest delay in nitrogen cycling through slower decay rates and sustained periods of nitrogen immobilization. Therefore, both Ojibwe cosmological worldviews and my experimental research recognize wild rice population cycles as part of healthy ecosystem functioning. Interest in these cycles is part of a larger interest in wild rice protection, central to the spiritual and cultural integrity of Ojibwe. Due largely to Ojibwe initiatives, legislation passed in Minnesota 2007 requiring submission of an Environmental Impact Statement in the case of a permit to genetically engineer wild rice either within or outside Minnesota. These efforts are part of a long history of Ojibwe attempt to address the cultural implications of Western scientific inquiry, inquiry often made without their consent. In the last chapter of this thesis, I examine the cultural background of this political process, concluding that the historical and political context of scientific investigation is critical to exposing weaknesses in research questions and political processes.
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    Wild Rice: The Minnesota Legislature, a Distinctive Crop, GMOs, and Ojibwe Perspectives
    (2009) Walker, Rachel Kurkee; Doerfler, Jill
    This 26 page legal brief summarizes the history of treaty law, political debate, legislation in Minnesota related to wild rice, as well as the industry position (especially for Monsanto). The LEXISNEXIS Summary is reproduced below: “ ... Monsanto has never thought about engineering wild rice. ... History of Wild Rice Legislation in Minnesota In the 2005 legislative session, the Minnesota Senate tabled S.F. 1566, a version of the "wild rice bill" that prohibited the release and sale of genetically engineered wild rice in Minnesota. ... These explanations discount the legal realities of American Indian sovereignty and treaty-secured resource management, as well as the significance of the rights of sovereign nations to preserve Ojibwe identity and livelihood. ... From approximately the 1950s, with the introduction of cultivated wild rice and an increase in national and international market sales, some non-Indians grew increasingly interested in participating in wild rice cultivation and harvest. ... The following quotations from legislators during legislative hearings in 2006 and 2007 and from cultivated wild rice marketing companies capture some of the sentiments that non-Indian Minnesotans have with respect to both cultivating and eating wild rice: I am supporting this legislation because it is about wild rice and wild rice alone. ... At this point, we look briefly at the political and economic context of crop biotechnology in 2007 as it relates to this legislation. ... On March 31, 2007, the United States rice industry declared it wanted the federal government to reject a plan to grow genetically modified rice in Kansas, saying the country's growers would suffer "financial devastation" if modified crops contaminate the commercial supply.”