In geomicrobiology and biogeochemistry research, we strive to understand how microorganisms impact and control important geological processes, including mineral dissolution and mineral precipitation, and the distribution of elements in diverse environments at and below the Earth's surface. Because of active (and sometimes passive) microbial metabolism, the surrounding environment can geochemically and physically change over time. These changes, in turn, exert control on the evolution and structure of the microbial communities. The faculty and students of the Department of Geology and Geophysics are engaged in an assortment of interdisciplinary geomicrobiological and biogeochemical research projects. The excellent analytical facilities at LSU permit the multidisciplinary characterization of the nature of the interactions between microbes and Earth's materials through space and time, including microbiological, geological, chemical, and isotopic analyses.

Fe-S framboids forming in a dense biological slime with iron-reducing bacteria and sulfate-reducing bacteria (Engel)

Environmental geomicrobiology and microbial ecology of geologic processes

• Geomicrobiological characterization of subsurface porosity in karst
• Microbially induced transformations in the carbon, sulfur, nitrogen cycles
• Biomineralization and microbial interactions with rocks
• Molecular diversity and microbial ecology of sulfidic karst systems
• Metabolic and molecular diversity of microbes from extreme environments
• Biogeochemical processes controlling As and Sb speciation and mobility
• Biogeochemical processes controlling retention and mobilization of suspected pollutants
• Fate and transport of organic and microbial contaminants in porous media
• Development of methods to characterize microbial communities in subsurface environments

Early Earth genesis, mantle evolution, atmosphere and Mars surface

• Komatiite petrogenesis with implications for mantle evolution
• Early atmosphere and ocean, Archean-Proterozoic transition (2.0-2.5 Ga), the rise of atmospheric O2, and their links to biological evolution
• Geochemical and mineralogical signatures of large meteorite impacts
• Evolution of surface materials on Mars-history of water, spectroscopic analysis

Atmospheric chemistry

• Use of stable isotopes to understand sulfur and nitrogen cycles in the atmosphere and surface environments at present and in Earth's early history.

Microbe-invertebrate interactions

• Molecular cophylogeny of the symbiotic association of sulfur-oxidizing bacteria and lucinid bivalves.
• Stable isotope analysis of symbiotic association.

• Geomicrobiology lab for culture and molecular analyses (website)
• Finnigan MAT 262 thermal ionization mass spectrometer
• Finnigan MAT 253 gas source mass spectrometer
• Agilent 6890/5973 gas chromatograph mass spectrometer
• Agilent 1100 liquid chromatograph
• Laser-fluorination and vacuum line systems
• Perkin Elmer 3300 DV dual view inductively coupled plasma optical emission spectrometer
• Perkin Elmer 3300 atomic absorption spectrometer
• Dionex 500 and ICS-90 ion chromatograph systems
• Class 100/1000 ultraclean laboratory
• Class 100/1000 ultraclean laboratory
• JEOL 840A scanning electron microscope (lab website)
• JEOL JXA-733 electron microprobe
• Siemens D5000 automated powder X-ray diffractometer
• Synchrotron x-ray source, LSU Center for Advanced Microdevices
• Sun Ultra60's and Blade workstations