The Hamersley Environmental Microbiology Laboratory

Research Projects

Methane Production from Wetlands

Methane in the atmosphere is an important contributor to greenhouse warming and climate change. Most of the methane in the atmosphere is produced by microorganisms living in wetland sediments where no oxygen is available. The laboratory is studying the role of nutrients commonly found in urban and agricultural runoff in inhibiting the production of methane from sediments.

Selected Publications and Conference Presentations (*student co-authors)

Hamersley MR, Tan CM* and Kanoka K*. Co-inhibition of wetland methanogenesis by nitrate and sulfate (Newport Bay , CA). Poster, Association for the Sciences of Limnology and Oceanography Aquatic Sciences Meeting. February 24-March 2, 2019. San Juan, Puerto Rico, USA.

Tan CM* and MR Hamersley. Interactive effects of nitrate and sulfate on methane production in an urban wetland (Newport Bay , CA). Poster, 43rd West Coast Biological Sciences Undergraduate Research Conference. April 14 2018, Saint Mary’s College of California, Moraga, California, USA.

Kanaoka K* and MR Hamersley. Inhibition of methanogenesis by nitrate and denitrification intermediates in fresh- and saltwater urban wetland sediments. Society of Wetland Scientists Conference. May 31-June 4, 2016. Corpus Christi, Texas, USA.

Tran QV*, Takeuchi M*, Mouginot C and MR Hamersley. Methanogenic diversity and methane efflux across two vegetation zones of an urban freshwater wetland. Poster, 13th Annual Southern California Geobiology Symposium, California Institute of Technology, May 7, 2016. Pasadena, California, USA.

Preservation of Organic Matter in Martian Fluvio-Lacustrine Sediments

Robotic probes on Mars, such as the Curiosity Mars Science Laboratory, are searching for the chemical signatures of life on Mars. In collaboration with researchers from the Planetary Science Institute and NASA, the laboratory is studying the mechanisms for the preservation of organic matter over geological time-scales in the 200-million-year-old river and lake sediments of the Painted Desert, which are analogous to environments on Mars where organic matter has been found preserved.

Selected Publications and Conference Presentations

Noe Dobrea EZ, McAdam AC, Freissinet C, Franz H, Belmahdi I, Hamersley MR, Archer R, Stoker CR, Parker WG, Glavin DP and Calef F. Mechanisms for preservation of organics in jarosite at the Painted Desert. Oral presentation and abstract, Astrobiology Science Conference. April 24-28, 2017. Mesa, Arizona, USA.

Noe Dobrea, EZ, McAdam AC, Freissinet C, Franz H, Belmahdi I, Hamersley MR, Stoker CR, Parker B, Ja Kim K, Glavin DP, Calef F and AD Aubrey. Characterizing the mechanisms for the preservation of organics at the Painted Desert: Lessons for MSL, ExoMars, and Mars 2020. Abstract 2796. Poster and abstract, 47th Lunar and Planetary Science Conference. March 21-25, 2016. The Woodlands, Texas, USA.

Noe Dobrea EZ, Aubry AD, Glavin DP, Calef F, Hamersley MR, McAdam AC, Freissinet C, Franz H, Stoker CR and B Parker. Biologically induced mineralization, site selection, and organic detection in Mars-analog field sites. Oral presentation and abstract, Astrobiology Science Conference: Habitability, Habitable Worlds, and Life. June 15-19, 2015. Chicago, Illinois, USA.

Major Instrumentation 

• Chemiluminescence detector, Teledyne 200E
• Elemental CHNS analyzer, Perkin Elmer 2400II
• Fluorometer, Turner Trilogy
• Gas Chromatograph (Greenhouse and permanent gasses, Bruker 450-GC; Flame ionization detection, Shimadzu Mini-2)
• Infrared CO₂ analyzer, Milton Roy
• Isotope Ratio Mass Spectrometer, IsoPrime PrecisION Lyophylization system, Labconco
• Microsensor microprofiling system, Unisense
• Ultramicrobalance, Perkin Elmer AD-6 Vacuum Centrifuge, Labconco Centrivap

Collaborating Laboratories and Institutions

• Back Bay Science Center
• Jet Propulsion Laboratory | Caltech
• Max Planck Institute for Marine Microbiology | Bremen, Germany
• Planetary Science Institute
• UC Davis Stable Isotope Facility
• UCLA Department of Atmospheric and Oceanic Sciences
• University of Southern California Department of Marine Environmental Biology | USC Wrigley Center for Environmental Studies