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Downers Grove South High School ESRP 2013

Prevalence of Biomarkers in Mazon Creek Fauna

Authors:

  • Students:
    • Sam Boroumand
    • Crystal Loehman
    • Julian Martinez
    • Andrew Molina
    • Caroline Purcell
    • John Shimanek
    • Rachel Smith
    • Apoorva Sooranahalli
  • Teachers:
    • Theresa Quain
  • Mentors:
    • Antonio Lanzirotti (University of Chicago, GSECARS)

Advanced Photon Source Sector 13: GSECARS

The goal of the experiment was to determine what metal or metalloid biomarkers were preserved in a fossil of an Esconites zelus fossil from Mazon Creek. X-ray fluorescence imaging was used to map out the metals and metalloids in the mouth region of the worm. Results showed high concentrations of As and Fe in the areas around the palps and throat of the worm, with no other elevated concentrations of As around the body. The large amounts of Fe were attributed to the iron siderite of which the fossil is composed. Arsenic in water is known to adsorb onto the surface of iron siderite. The arsenic was found mainly outside the body of the worm or in the cavity of the throat region. The presence of organic molecules in the decaying worm may have facilitated this adsorption of As from seawater during the fossilization process.

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