Michael Shields

Michael Shields

Assistant Research Scientist

Organic Geochemistry, Biogeochemistry, Chemical Biomarkers


  (979) 458-9322

  GERG 116


I study the biogeochemistry of terrestrial, riverine, estuarine, and open ocean environments with an emphasis on carbon preservation and sequestration mechanisms.

My research focuses on the application of organic compounds as chemical biomarkers in tandem with carbon and nitrogen isotopes to track the sources and the diagenetic state of organic matter in sediment, soil, freshwater, estuarine, and open ocean ecosystems.  In addition to modern processes, these chemical biomarkers record past environmental conditions and bio/geochemical processes.

Along with current research on natural organic matter, I am now incorporating both traditional and emerging organic contaminants such as PFAS into my research, which likely play a significant biogeochemical role in the Anthropocene.

Selected Publications

Recent First Author Publications (See CV or Google Scholar for complete list):


Shields, M.R., Bianchi, T.S., Osburn, C.L., Kinsey, J.D., Ziervogel, K., Schnetzer, A., Corradino, G., 2019. Linking chromophoric organic matter transformation with biomarker indices in a marine phytoplankton growth and degradation experiment. Mar. Chem. 214, 103665. https://doi.org/10.1016/j.marchem.2019.103665


Shields, M.R., Bianchi, T.S., Kolker, A.S., Kenney, W.F., Mohrig, D., Osborne, T.Z., Curtis, J.H., 2019. Factors controlling storage, sources, and diagenetic state of organic carbon in a prograding subaerial delta: Wax Lake Delta, Louisiana. J. Geophys. Res. Biogeosciences 2018JG004683. https://doi.org/10.1029/2018JG004683


Shields, M. R., T. S. Bianchi, D. Mohrig, J. A. Hutchings, W. F. Kenney, A. S. Kolker, and J. H. Curtis. 2017. Carbon storage in the Mississippi River delta enhanced by environmental engineering. Nat. Geosci. doi:10.1038/ngeo3044


Shields, M. R., T. S. Bianchi, Y. Gélinas, M. A. Allison, and R. R. Twilley. 2016. Enhanced Terrestrial Carbon Preservation Promoted by Reactive Iron in Deltaic Sediments. Geophysical Research Letters. 1–25. doi:10.1002/2015GL067388


Five Recent Publications (See CV or Google Scholar for complete list):

Morrison, E.S., M.R. Shields, T.S. Bianchi, Y. Liu, S. Newman, N. Tolic, and R.K. Chu. Multiple biomarkers highlight the importance of water column processes in treatment wetland organic matter cycling. Water Research. 115153.


Arellano, A. R., T.S. Bianchi, C. Osburn, E J. D’Sa, N.D. Ward, D. Oviedo-Vargas, I. Joshi, D. Ko, M.R. Shields, G. Kurian, and J. Green. (2019). Mechanisms of Organic Matter Export in Estuaries with Contrasting Carbon Sources. Journal of Geophysical Research: Biogeosciences, 124(10), 3168–3188. https://doi.org/10.1029/2018JG004868


Yao, P., X. Wang, T.S. Bianchi, Z. Yang, L. Fu, Z. Yu, X. Zhang, L. Chen, E. Morrison, M.R. Shields, Y. Liu, N. Bi, Y. Qi, S. Zhou, J. Liu, Y. Tian, X. Huang, J. Wang, D. Wu, H. Zhang, C. Zhu, C. Deng, and Z. Yu. Carbon cycling in the ocean’s deepest blue hole.  J. Geophys. Res. – Biogeosci., 125(2): e2019JG00530.


Paerl, R.W., I.M. Claudio, M.R. Shields, T.S. Bianchi, and C.L. Osburn, 2020. Dityrosine formation via reactive oxygen consumption yields increasingly recalcitrant humic-like fluorescent organic matter in the ocean. Limnol. Oceanogr. Lett. https://doi.org/10.1002/lol2.10154


Vaughn, D.R., T.S. Bianchi., M.R. Shields, W.F. Kenney, and T.Z. Osborne, 2020. Increased Organic Carbon Burial in Northern Florida Mangrove‐Salt Marsh Transition Zones. Global Biogeochem. Cycles 34, 1–21. https://doi.org/10.1029/2019GB006334


Fortney, N, B. Beard, J. Hutchings, M. Shields, T. Bianchi, E. Boyd, C.M. Johnson, and Roden. Geochemical and stable Fe isotopic analysis of dissimilatory microbial iron reduction in Chocolate Pots hot spring, Yellowstone National Park (Accepted). Astrobiology


PhD in Geological Sciences from the University of Florida (2016)

BS in Biochemistry from Texas A&M University (2011)


Additional Notes

Scientific Committee Member of the International Estuarine Biogeochemistry Symposium

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