Meeting/Event Information

AIPG MN & AWG MN - June Luncheon - Using reactive transport modeling to link hydrologic flux and root zone geochemistry at Second Creek, a sulfate enriched wild rice stream in northeastern Minnesota!!

June 06, 2017
11:45 AM to 1:00 PM
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Radisson Hotel Roseville
2540 North Cleveland Avenue
Roseville, MN 55113


Registration for the AIPG MN Section June Luncheon in cooperation with the Association for Women Geoscientists (AWG) Minnesota Chapter is now open online! The cost is $21 for non-members and $16 for members when registering before Monday, June 5, 2017 at 11:00 AM. Students may attend free of charge by registering in advance. Same-day luncheon registration cost is $25.


Using reactive transport modeling to link hydrologic flux and root zone geochemistry at Second Creek, a sulfate enriched wild rice stream in northeastern Minnesota

by Amanda Yourd, University of Minnesota


Presentation Abstract

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.



Speaker Biography

Amanda Yourd recently finished her Master's in hydrogeology at the University of Minnesota in Minneapolis, where she studied groundwater-surface water interaction and geochemistry on the Iron Range in northern Minnesota. She received a Bachelor's degree in geology from Carleton College in 2011, and has been involved in Earth Science research and education ever since.  Most recently, she taught a two-month field geology course to middle school students in Cambodia.   



$16.00 AIPG Member

$21.00 Non-Member

$0.00 Student