Team Zaaga’igan conducts research on the effects of sulfur on wild rice with Dr. Nathan Johnson, a civil engineering professor at the University of Minnesota, Duluth as well as Sophie LaFond-Hudson, a graduate student that is directly working on the research project. Our study also includes a collaboration with Nancy Schuldt the Fond du Lac Resource Management of the Lake Superior Chippewa.
The work that will be conducted by our team this summer is of crucial importance for the Native American tribes in Minnesota. Wild-rice not only occupies an important part on their diet it is also of great spiritual importance to the tribes. The wild-rice is considered sacred as a symbol that led their people to the lands that have become their home and their legacy.
Not only is it part of the Native American culture it has also become part of Minnesota’s culture as the official state grain. This importance has fueled multiple disputes as well as law proposals to protect the rice from pollution. A state law decreed in 1973 set a standard to protect it from sulfate pollution limiting the amount of sulfate that can be discharged in wild-rice producing waters. In recent years mining companies have tried to eliminate the law or at least weaken it without considering that a weakening of the sulfate standards could kill the wild-rice population.
Sulfide mining is an environmentally risky practice in which sulfide ores are mined in order to extract precious metals such as copper and nickel. The environmental impact of sulfide mining is well documented and new proposals for mining in Minnesota have the potential to significantly affect local water systems [1,2]. Sulfide mining is uniquely problematic because sulfide mines produce a large amount of toxic runoff that easily leaches out into the groundwater. These pollutants have the potential to proliferate out into the environment and become bioavailable. Perturbations to ecosystem health, including the decline of fish and plant populations, have been observed in environments introduced to increased sulfate and sulfide concentrations. The sulfur increases acidity and makes the water inhospitable for many aquatic vertebrates, while also inhibiting photosynthetic activity in plants that incorporate the sulfur through their roots. (maybe cut this last sentence?)
One plant community expected to be significantly impacted is wild rice. Wild Rice is an important part of Minnesota ecology and is a staple to the diet of many indigenous peoples of Northern Minnesota. Pastor et al. released a study this year demonstrating a plethora of effects that sulfide has on wild rice reproduction and development. Wild rice growth, reproductive success, and survival were all negatively impacted by the presence of sulfide in their environment.
The goal of Team Zagaa’igan this summer will be to investigate how plant-controlled redox changes in sediment affect precipitation of minerals on the roots of wild rice. We will investigate this inquiry with two experiments one of which tests the survival of seedlings in varying depth and sulfide trials. The second one will observe effects of iron oxides on inhibiting sulfide from plant roots by isolating the roots from photosynthetic capabilities. Wetland plants growing in anoxic sediment are exposed to reactive compounds which can form precipitates with the oxygen that is leaked from plant roots. The formation of iron oxides protect the plant against sulfides that inhibit plant functioning. Two experiments will be conducted the first of which investigating iron oxide formation on seedlings.
Our hypothesis is that iron oxides will form on root surfaces as the plant emerges from the surface of the water, due to increased photosynthesis. We will germinate two sets of plants, one set in sediment with a shallow water column and one set in sediment with a tall water column. We expect to see seedlings grown in shallow water develop iron oxides sooner than seedlings grown in deeper water. The second part of the research will consist of decreasing the supply of oxygen to the roots. The experiment will be performed by cutting off the stems off half of the wild rice specimens and keeping the stem on others. This will affect the wild rice, since the stem is the main source of oxygen transportation for the plant. Once the stem is removed, Team Zagaa’igan will begin monitoring the effects of iron oxides on the roots of the plant.