Associate Professor
Plant and Microbial Biology

Our research focuses on microbial photosynthesis and global biogeochemical cycles. We combine genomic, functional, and evolutionary studies of complex microbial ecosystems to answer outstanding questions in microbial ecology and evolution including the form and function of the Earth’s earliest phototrophs and the contribution of these organisms to biogeochemical cycling in Earth’s past, present, and future.

Expand all

Research statement

Our lab studies the functions and interactions of microorganisms in natural and engineered systems and how microbial communities respond and adapt to environmental change. We are particularly interested in life at the fringe including redox gradients and temperature extremes.  We use traditional microbiology and molecular techniques as well as next generation -omics approaches in combination with high resolution geochemical and geological data. The integration of these data results in a multidisciplinary approach to examine the in situ dynamics of microbial interactions and the affect of these interactions on local and global biogeochemical cycles. Ongoing projects in the lab include: 1) microbial primary productivity in the Proterozoic oceans; 2) the limits of chlorophototrophy (from glaciers to hot springs); 3) competitive interactions and microbial community assembly; 4) the Ecology and Physiology of toxin-producing Cyanobacteria. For more information, please visit the lab's website.

Selected publications

  • Berberich, M.E., Beaulieu, J.J., Hamilton, T.L., Waldo, S., Buffam, I. (2019) Spatial variability of sediment methane production and methanogen communities within a eutrophic reservoir: importance of organic matter source and quantity. Limnology and Oceanography. In press. (doi: 10.1002/lno.11392)
  • Gangidine, A., Havig, J.R., Fike, D., Jones, C., Hamilton, T.L., Czaja, A.D. (2019) Trace element concentrations in hydrothermal silica deposits as a potential biosignature. Astrobiology. In press. (doi: 10.1089/ast.2018.1994)
  • Hamilton, T.L., Bennett, A.C., Murugapiran, S., Havig, J.R. (2019) Anoxygenic phototrophs span geochemical gradients and diverse morphologies in terrestrial geothermal springs. mSystems 4:e00498-19. (doi: 10.1128/mSystems.00498-19)
  • Holmes, C.J., Jennings, E.C., Gantz, J.D., Specht, D., Spangler, A.A., Denlinger, D.L., Lee Jr., R.E., Hamilton, T.L., Benoit, J.B. (2019) The Antarctic mite, Alaskozetes antarcticus, shares bacterial microbiome community membership but not abundance between adults and tritonymphs. Polar Biology. 42: 2075. (doi: 10.1007/s00300-019-02582-5)
  • Jennings, E.C., Korthauer, M.W., Hamilton, T.L., Benoit, J.B. (2019) Matrotrophic viviparity limits the microbial community until after birth in the cockroach, Diploptera punctata. Ecology and Evolution. 9: 10601-10614. (doi: 10.1002/ece3.5580)
  • Havig, J.R., Hamilton, T.L. (2019) Productivity and community composition of low biomass/high silica precipitation hot springs: a possible window to Earth’s early biosphere? Life. 9, 64; doi:10.3390/life9030064
  • Hamilton, T.L. (2019) The trouble with oxygen: The ecophysiology of extant phototrophs and implications for the evolution of oxygenic photosynthesis. Free Radical Biology & Medicine. 140, 233-249. (doi: 10.1016/j.freeradbiomed.2019.05.003)*Invited Review*
  • Havig, J.R., Hamilton, T.L. (2019) Cryptic oxygen oases: Hypolithic photosynthesis in hydrothermal areas and implications for Archean surface oxidation. Frontiers in Earth Science - Biogeoscience. 7:15. (doi: 10.3389/feart.2019.00015)
  • Havig, J.R., Hamilton, T.L. (2019) Snow algae drive productivity and weathering at volcanic rock-hosted glaciers. Geochimica et Cosmochimica Acta. 247, 220–242. (doi: 10.1016/j.gca.2018.12.024)
  • Hamilton, T.L., Welander, P., Albrecht, H.L., Fulton, J.M., Schaperdoth, I., Bird, L., Summons, R., Freeman, K.H., Macalady, J.L. Microbial communities and organic biomarkers in a Proterozoic-analog sinkhole environment. In Press. Geobiology. (doi: 10.1111/gbi.12252)
  • Havig, J.R., Grettenberger, C., Hamilton#, T.L. Geochemistry and microbial community composition across a range of acid mine drainage impact and implications for the Neoarchean-Paleoproterozoic transition. Journal of Geophysical Research: Biogeosciences. 122: 1404–1422. (doi:10.1002/ 2016JG003594)
  • de Beer, D., Weber, M., Chennu, A., Hamilton, T.L., Lott, C., Macalady, J.L., Klatt, J. (2017) Oxygenic and anoxygenic photosynthesis in a microbial mat from an anoxic spring, Little Salt Spring. Environmental Microbiology. 19: 1251–1265. (doi: 10.1111/1462-2920.13654)
  • Hotaling, S., Hood, E., Hamilton#, T.L. Microbial ecology of the alpine cryosphere: glaciers, subglacial environments, and meltwater streams. In press. Environmental Microbiology. (doi: 10.1111/1462-2920.13766)
  • Hamilton, T.L., Havig, J.R. (2016) Supraglacial primary productivity in glaciers on stratovolcanoes of the Pacific Northwest. In press. Geobiology. (doi:10.1111/gbi.12219)
  • Harrold, Z.R., Skidmore, M., Hamilton, T.L., Desch, L., Amada, K., van Gelder, W., Roden, E., Boyd, E.S. (2015) Aerobic and anaerobic thiosulfate oxidation by a cold-adapted, subglacial chemoautotroph. Applied and Environmental Microbiology. 82:1486-1495. (doi: 10.1128/AEM.03398-15)
  • Hamilton, T.L., Bovee R.J., Sattin S.R., Mohr, W., Gilhooly III, W.P., Lyons, Pearson, A., Macalady, J.L. (2016) Carbon and sulfur cycling below the chemocline in a meromictic lake and the identification of a novel taxonomic lineage in the FCB superphylum, Candidatus Aegiribacteria. 7: 00598. Frontiers in Microbiology. (doi: 10.3389/fmicb.2016.00598)
  • Telling, J., Boyd, E.S., Bone, N., Jones, E., Tranter, M., J.L., MacFarlane, Martin, P., Wadham, J., LaMarche-Gagnon, G., Skidmore, M.L., Hamilton, T.L., Hill, E., Jackson, M., Hodgson, D.A. (2015) Rock comminution as a source of hydrogen for subglacial ecosystems. Nature Geoscience. 8, 851–855. (doi:10.1038/ngeo2533)
  • Havig, J., McCormick, M.L., Hamilton, T.L., Kump, L.R. (2015) The behavior of biologically important trace elements across the oxic/euxinic transition of meromictic Fayetteville Green Lake, New York, USA. Geochimica et Cosmochimica Acta. 165:389-406. (doi: 10.1016/j.gca.2015.06.024)