Browsing by Subject "wild rice"

Now showing 1 - 7 of 7
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    The Effect of Sulfate Contamination of Water on Wild Rice Nutrient Composition
    (2023-02) Johnson, Katelyn
    Sulfate contamination of waters where wild rice grows threatens its survival. Toxic levels of sulfate affect growth and development, which leads to reductions of natural stands. Research shows that when sulfate is reduced to sulfide, it interacts with iron in sediment to precipitate iron-sulfide. Iron-sulfide plaques accumulate on wild rice roots, which inhibits nutrient uptake from soil. This study examined changes in wild rice nutrient composition by analyzing rice samples grown in low-sulfate and high-sulfate waters under natural and experimental conditions. Samples collected from experimental mesocosms included “low-sulfate’ controls (10 mg/L SO4) and “high-sulfate” amended (300 mg/L SO4). Natural site samples collected from two bodies of water surrounding the Great Lakes Region; Big Rice Lake (“low-sulfate” non-detect) and Sand River (“high-sulfate” > 46.2 mg/L SO4), respectively. We measured antioxidant capacity, plant secondary metabolites, total starch, and mineral content, including mercury, of eight wild rice samples. Wild rice exposed to sulfate in natural and controlled environments had decreased seed sizes and weight. Reductions in seed size appeared due to a reduced amount of starch, as starch content and seed size were highly correlated. Certain trace minerals were reduced to a greater degree than the reduction in seed size, particularly iron, copper, and zinc. Since iron and copper are both required for starch synthesis, and copper deficiency increases synthesis of starch-degrading enzymes, deficiencies of copper and iron may be responsible for the reduced starch content of the wild rice seeds, thus producing a smaller seed size.
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    Identifying and Interpreting Contemporary Wild Rice Habitat in Ceded Chippewa Lands of Northern Minnesota.
    (Center for Community & Regional Research, College of Liberal Arts, University of Minnesota, Duluth., 1995) Henderson, Martha L
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    Iron Sulfide Formation on the Root Surfaces of Wild Rice
    (2017-08-16) LaFond-Hudson, Sophia; Johnson, Nathan; Pastor, John; Dewey, Brad; lafo0062@d.umn.edu; LaFond-Hudson, Sophia
    The data are from an experiment showing life-cycle induced iron sulfide formation on root surfaces of wild rice. Plants with and without added sulfate were harvested during the reproductive stage of the life cycle to quantify concentrations of iron and sulfide on root surfaces. Seed and plant N was measured to examine the effect of iron sulfide root plaques on seed production. On amended roots, iron transitioned from mostly Fe(III) to mostly Fe(II) as sulfide concentrations increased rapidly. Amended plants produced fewer, lighter seeds with less nitrogen.
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    Mercury Uptake by Wild Rice Plants in Northern Minnesota
    (2015-09) Mahr, Christopher
    Mercury (Hg) is a naturally occurring element that can be taken up by microbes, converted into toxic, organic methylmercury (MeHg), and exported into surrounding sediment. The MeHg can then be taken up by plants through rhizofiltration. In Minnesota, 2-4 million lbs of Wild Rice is harvested each year and 1 lb yield 10.5 cups of rice. This study involves sampling surface water, surface sediment, and wild rice grains from 6 lakes on the White Earth Reservation, Fond du Lac Reservation, and 1854 Treaty Area in Minnesota. This was done in order to assess a possible toxicity risk from the consumption of Wild Rice. Finished and unfinished rice grains were analyzed, and all samples were consistent for the six lakes. Using a chronic exposure formula and the highest THg and MeHg concentrations in finished rice grains, it was determined that the toxicity in wild rice grains in Minnesota is extremely low.
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    Using reactive transport modeling to link hydrologic flux and root zone geochemistry at Second Creek, a sulfate enriched wild rice stream in northeastern Minnesota
    (2017-02) Yourd, Amanda
    Wild rice (Zizania palustris) is an economically, culturally, and ecologically important aquatic plant species in Minnesota. In northeastern Minnesota, iron ore and taconite mining have led to elevated surface water sulfate concentrations, which has raised concern about the potential of sulfate negatively impacting wild rice populations. Recent studies have shown that elevated sulfide concentrations in the wild rice root zone (sediment porewater) is more closely correlated with lower occurrence of wild rice than surface water sulfate. This toxic porewater sulfide can be attenuated by precipitation of iron sulfide minerals if dissolved ferrous iron is locally available. Although these geochemical reactions occur in the sediment porewater, or hyporheic zone, where groundwater and surface water mix, the effect of groundwater flux and geochemistry on geochemical processes within the hyporheic zone has not been examined in the context of wild rice and sulfate. Here, we use physical and geochemical field data collected from surface water, porewater, and groundwater to inform a reactive transport model of Second Creek, a mining impacted wild rice stream in northeastern Minnesota. The model is implemented for different hydrologic flux regimes in different locations at Second Creek to examine the geochemical response of the sediment porewater to changes in both physical and geochemical conditions. We show that porewater sulfide concentrations can are dependent on hydrologic flux direction and magnitude, as well as on concentrations of surface water sulfate, sediment organic carbon, and porewater iron. This work emphasizes the importance of constraining groundwater flux and geochemistry when examining processes at the groundwater-surface water interface.
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    Wild Rice/Ground Beef Mixtures
    (St. Paul, MN: University of Minnesota Extension Service, 1995) Epley, Richard J.; Minerich, Philip L.; Addis, Paul B.
    This fact sheet describes a study designed to find a palatable combination of wild rice and ground beef that would have nutritional advantages to 100 percent ground beef. Includes the design, results, and conclusions of the study, plus manufacturing procedure to make the mixture.