• Low temperature 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 specializes in developing and applying electrochemical techniques for in situ measurements in marine and freshwater sediments. We also conduct incubation experiments with natural samples to quantify the dynamics of biogeochemical processes and decouple biological from chemical processes. Finally, we build and apply mathematical models to diagnose our understanding of these processes using an inverse modeling approach.

The overall motivations of our work include: 1) predicting how the biogeochemical transformation of elements in aquatic systems is affected by a changing climate; 2) discovering new biogeochemical processes that regulate the transformation of metals of environmental relevance in aquatic systems; 3) developing new (bio)remediation techniques that exploit natural processes in aquatic systems; and 4) developing new analytical techniques for both laboratory and in situ measurements in aquatic systems

Current Funded Projects (updated 12/2022)

Effect of Hydrological Forcing on the Biogeochemical Transformation of Carbon and Greenhouse Gas Emissions in Riparian and Streambed Sediments. (Taillefert, Lead-PI; Arson, DiChristina, Kaplan, Kemner, co-PIs: DOE-ESS)

Importance of Riverine Discharge on the Benthic Flux of Alkalinity to Continental Margins. (NSF-Chemical Oceanography)

Role of Sediments in the Susceptibility to Ocean Acidification in Coastal Habitats (Tailllefert, Lead-PI; Lopanik, co-PI:NOAA Georgia SeaGrant)

Development of Innovative Techniques for Exploring Novel Submarine Springs on the Gulf of Mexico Out-Continental Shelf (Hall, PI; Beckler, Taillefert, Stewart, Co-PIs: NOAA Ocean Exploratory Research)

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)

Past Projects (last 5 years only)

Integration of Omics into a New Comprehensive Rate Law for Competitive Terminal Electron-Accepting Processes in Reactive Transport Models (Taillefert, Lead-PI; DiChristina, Stewart, Brooks (ORNL), Kemner (ANL), co-PIs)

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

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)

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)