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Elizabeth S. Swanner

Elizabeth S Swanner

  • Associate Professor
  • Geological and Atmospheric Sciences

Contact Info

354 Science
2237 Osborn Dr.
Social Media and Websites


  • PhD, Geology, University of Colorado, 2011
  • AB, Biochemistry, Mount Holyoke College, 2003

More Information

Overview and significance of research 

The habitability of Earth is the result of microbial life forging the way, and partitioning Earth’s elemental inventory in a way that was favorable for the development of animal and intelligent life. Of critical importance to life is the element iron, whose behavior and mobility in the environment are highly nuanced and coupled to microbial and geological processes at all temporal and spatial scales. Photosynthesis, developed in the bacterial line, dramatically reorganized the global iron and carbon cycles as it oxygenated the atmosphere over two billion years of Earth’s history. Uncovering this history requires identifying and looking for mineral, isotopic, and elemental signatures of photosynthetic activity and iron cycling. The story of photosynthesis continues into the modern, and understanding bacterial photosynthesis in freshwaters, particularly lakes, can give both insight into past periods and transitions, as well as the harmful algal blooms that threaten the safety of our surface waters today.


Broader impacts of my research 

My research since arriving at Iowa State has transitioned from being primarily experimental to observational, comprised of field work and analysis of natural samples. I have taken advantage of regional field sites, specifically lakes, to ask and answer both questions regarding biogeochemical cycling through time, but also to investigate how the microbes I study influence our environment and climate now. I am pioneering the identification of permanently anoxic and iron-rich lakes in the Midwest, which can be used to better understand biogeochemical cycling in past iron-rich oceans. These lakes offer a window into the uncovered modern iron cycle between lakes and the terrestrial environment, and are opening up new research directions connecting to hydrogeology and astrobiology. From the sediments that form in iron-rich lakes, I have found new connections to the interpretation of the genesis of past iron-rich sediments, applying lessons from these modern analogues. Through the lens of connections between iron and photosynthesis, I have been able to establish research on harmful algal blooms in Iowa lakes, endeavors that yield benefits for the citizens of Iowa through connections with the Iowa Department of Natural Resources and tie my research to ISU’s land-grant mission. This research area in particular opens a wider range of applications and career opportunities for the students I train.


Geochemistry and Geobiology Laboratory
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