• Geochemistry of aquatic environments
      • Chemical oceanography
      • Geomicrobiology
      • Environmental analytical chemistry
      • Environmental engineering


Our group is interested in the mechanisms of transformation of inorganic geochemical species in aquatic systems. Our objective is to quantify the dynamic cycling of metals at redox transitions by using a combination of field measurements, laboratory experiments with natural samples, and mathematical modeling.

Our group is specialized in the development and application of electrochemical techniques for in situ measurements in marine and freshwater sediments. To quantify the dynamics of biogeochemical processes and decouple biological from chemical processes, we conduct incubation experiments with natural samples. Finally, we build and apply mathematical models to diagnose our understanding of these processes using an inverse modeling approach.

Current Funded Projects (updated 10/2015)

Microbially driven Fenton Reaction: Development of Alternative Ex Situ and In Situ Remediation Technologies For 1,4-Dioxane, Tetrachloroethene, Trichloroethene, and Perfluoroalkyl Substances. (DiChristina, Biology, Georgia Tech, Lead-PI: DOD-SERDP)

Source, Composition, and Stability of Soluble Iron Fluxing from Continental Margin Sediments  (NSF Chemical Oceanography Program)

Effect of Low Concentrations of Arsenic on Microbial Iron Reduction (Tom DiChristina, Biology, Georgia Tech, co-PI:, NSF EAR Geobiology and Low Temperature Geochemistry Program)

Past Projects (last 5 years only)

Molecular mechanism of microbial metal respiration – electron shuttling by endogenous organic sulfur compounds (Tom DiChristina, Biology, Georgia Tech, lead-PI: NSF MCB Biomolecular Systems Program)

A New High Pressure Liquid Chromatography System for In Situ Measurements in Marine Pore Waters (Don Nuzzio, Analytical Instrument Systems, Inc., co-PI: NSF OCE – OTIC Program)

Mineral Solubility and Free Energy Controls on Microbial Reaction Kinetics: Application to Contaminant Transport in the Subsurface (Philippe Van Cappellen, Geochemistry, U. Waterloo, co-PI: Department of Energy, Office of Biological and Environmental Research)

The importance of anaerobic manganese respiration in the cycling of nitrogen in sediments (Tom DiChristina, Biology, Georgia Tech, co-PI: NSF EAR Geobiology and Low Temperature Geochemistry Program)

Promoting uranium immobilization by the activities of microbial phosphatases
(Patty Sobecky, Biology, U. Alabama, lead-PI: Department of Energy, Office of Biological and Environmental Research)

Processes controlling the release of iron from continental margin sediments                              (NSF Chemical Oceanography Program)