​Alexander S. Bradley

Alexander S. Bradley

Alexander S. Bradley

​Associate Professor of Earth, Environmental, and Planetary Sciences
Director of Graduate Studies
PhD, Massachusetts Institute of Technology
Research interests:
Organic and Isotope Geochemistry
  • Geobiology
  • Microbiology
    View All People

    Contact info:

    Mailing address:

    • MSC 1169-204-110 Washington University in St. Louis 1 Brookings Drive St. Louis, MO 63130-4899

    ​Alex Bradley studies the coevolution of life and the Earth. He is interested in using techniques from both geochemistry and biology to better understand the history of life and how biogeochemical cycles have changed through Earth history.

    One part of Professor Bradley's work pertains to the study of organic geochemistry. Organic geochemistry involves the characterization of the molecular structures and stable isotopic compositions of biological products detected in the environment. The information obtained from these molecules can be used in a wide range of applications, from understanding the cycling of carbon through ecosystems, to characterizing petroleum, to examining environmental contaminants, to reconstructing paleoclimate.

    Another part of his work involves conducting laboratory experiments to gain a better understanding of the information contained in geochemical biomarkers. Many aspects of physiology and environment can influence the suite of products produced by different organisms, as well as the stable isotopic compositions of the products. Through careful laboratory experimentation, he works to arrive at a better understanding of how to interpret the signals we observe in the geochemical record.

    Professor Bradley's laboratory studies the biogeochemistry and geobiology of natural systems, with an emphasis on molecular products of life that can be preserved in the geological record. They focus on organic geochemistry and isotope geochemistry. This leads to an examination of the structures and isotopic compositions of natural products, the genes and regulatory networks required for their biosynthesis, the physiological conditions that lead to their biosynthesis, and the information that they contain. They conduct both field and laboratory investigations to try to gain a better understanding of local and global biogeochemical cycles, and how these have evolved over Earth history. Specific research projects can be found on the laboratory website.