Understanding the Microbial Activity involved in Forming Iron Caves in Brazil
[Past Projects]
Dr. John Senko and Melissa Mulford
Research Area:
In the Carajas region of Brazil, banded iron formation (BIF) and its cap rock of canga are highly resistant to erosion and are poorly soluble. Despite this, over 3,000 caves have formed at their interface (one of these caves is shown in the photo). Our previous research has shown that microbial communities from these caves include bacterial species capable of Fe(III) reduction and the community is capable of extensive Fe(III) reduction. We hypothesize that microbial Fe(III) reduction transforms the insoluble Fe(III)-oxides into soluble Fe(II), which is then mobilized out the system, allowing caves and voids to form. We believe the Fe(II) may be stabilized in solution by a chemical interaction with silicates from the BIF.
We are currently studying the process of Fe(II) and Si mobilization through microbially driven iron redox reactions and the effects dissolved silica has on iron redox reactions. We use bacterial cultures grown in both anaerobic and aerobic conditions with iron and silica. We then analyze these cultures with geochemical and biological analyses.
You will learn many skills including but not limited to: microbial culturing and analyzing techniques, geochemical analysis methods, data processing methods, and experimental design.
Click here to learn more about Dr. Senkos’ lab.
