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Phone: 979.845.5105
Fax: 979.845.6331
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Texas A&M University
O&M Building, Room 716A
MS 3146,
College Station, Texas 77843

Dr. Heath Mills

Assistant Professor

Ph.D. Applied Microbiology, Georgia Institute of Technology, 2004

B.S. Biology, Duke University, 1997


Dr. Heath Mills’s scientific goals and expertise include the use of molecular and biogeochemical techniques to describe microbial community structure and function from coastal marine ecosystems to deep subsurface environments. He has over ten currently funded projects that include describing microbial community ecology within the coastal hypoxic zone on the Louisiana/Texas Shelf and characterizing metabolically active microbial populations within the deep subsurface biosphere on a global scale. Thanks to a big involvement in the Integrated Ocean Drilling Program, he has research sites that span the Atlantic and Pacific Oceans and collaborators in eight countries as well as throughout the US. The breadth of projects and collaborators highlights the research success he and his lab have experienced over the past few years.


His main research focus gives him the labels of a Geomicrobiologist and a Molecular Microbial Ecologist. These titles are earned because he combines RNA-based molecular approaches with classical geochemical analyses and geological sediment and hard rock descriptions to characterize microbial community ecology. He has developed an RNA extraction method that isolates rRNA and mRNA from a wide range of environments. Combining RNA-targeted pyrosequencing with geochemical analysis has allowed him to carve out a unique niche. His work has produced over twenty publications in print with many more on the way.


While at Texas A&M, he has had success teaching established courses and developing new ones. He genuinely enjoys teaching and appreciates the opportunity to interact in a constructive manner with his students. Course reviews have been very positive with many graduate and undergraduate students appreciative of his style and enthusiasm. He typically teaches the following course schedule:


OCNG 251 (Introduction to Oceanography) in the fall;

OCNG 650 (Aquatic Microbial Ecology) in the spring of odd numbered years; 

OCNG 691 (Marine Microbial Molecular Methods) in the spring of even numbered years.

OCNG 491 (Undergraduate Research) when requested by students

Research Interests

  • Molecular characterization of microbial community structure and function
  • Deep subsurface life exploration with IODP and C-DEBI: Sediments and Hard Rock
  • Coastal biogeochemical cycles: Carbon, Nitrogen, Iron, Sulfur
  • Molecular bioremediation of terrestrial and marine systerms
  • New Area: Fungi in marine systems: coastal waters to the deep subsurface


  • Characterization of metabolically active microbial communites from IODP Expeditions: 316 (Nankai Trough), 320 (Equatorial Pacific), 325 (Great Barrier Reef), 329 (South Pacific Gyre), 336 (Mid-Atlantic Ridge).
  • Mechanisms Controlling Hypoxia: Northern Gulf of Mexico hypoxic zone microbiology
  • Iron and sulfur cycling in the Nueces Bay, TX, estuary
  • Culture-dependent and independant analysis of fungi in the deep subsurface


Assistant Professor – 2008-Present. Department of Oceanography, Texas A&M University, College Station, TX

Joint Appointment – 2008-Present. Ecology and Evolutionary Biology Interdisciplinary Department - Texas A&M University, College Station, TX

Joint Appointment – 2008-Present. Marine Biology Department - Texas A&M University, College Station, TX

Joint Appointment – 2008-Present. Ocean Drilling and Sustainable Earth Science (ODASES) Faculty – Associated with the Integrated Ocean Drilling Program (IODP)

Assistant in Research. 2004 – 2007. Faculty sponsor - Dr. Joel E. Kostka. Department of Oceanography, Florida State University, Tallahassee, FL


  • Reese, B.K., H.J. Mills, S.E. Dowd, and J.W. Morse. 2012. Linking molecular microbial ecology to geochemistry in a coastal hypoxic zone. Geomicrobiology. In press.
  • Mills, H.J., B.K. Reese, A.K. Shepard, N. Riedinger, Y. Murano, and F. Inagaki. 2012. Characterization of the metabolically active bacterial populations in subseafloor Nankai Trough sediments above, within and below the sulfate-methane transition zone. Frontiers in Extreme Microbiology: Deep Subsurface Microbiology. 3:113. doi: 10.3389/fmicb.2012.00113.
  • Mills, H.J., B.K. Reese, and C. St. Peter. 2012. Characterization of microbial population shifts during sample storage. Frontiers in Extreme Microbiology: Deep Subsurface Microbiology. 3:49. doi: 10.3389/fmicb.2012.00049
  • Expedition 336 Scientists, 2012. Mid-Atlantic Ridge microbiology: initiation of long-term coupled microbiological, geochemical, and hydrological experimentation within the seafloor at North Pond, western flank of the Mid-Atlantic Ridge. IODP Preliminary Report, 336. doi:10.2204/
  • Yokoyama, Y., J.M. Webster, C. Cotterill, J.C. Braga, L. Jovane, H. Mills, S. Morgan, A. Suzuki and IODP 325 Scientists. 2011. IODP Expedition 325 (GBREC) reveals past sea-level changes, climates and environmental changes in the Western Pacific during the last ice age and the deglaciation. Scientific Drilling. doi:10.2204/
  • Reese, B.K., D.W. Finneran, M.X. Zhu, H.J. Mills, and J.W. Morse. 2011. Examination and refinement of the determination of aqueous hydrogen sulfide by the methylene blue method. Aquatic Geochemistry. 17:567-582.
  • Expedition 325 Scientists, 2010. Great Barrier Reef environmental changes: the last deglacial sea level rise in the South Pacific: offshore drilling northeast Australia. IODP Preliminary Report 325. doi:10.2204/
  • Gihring, T.M., M. Humphrys, H.J. Mills, M. Huettel, and J.E. Kostka. 2009. Identification of phytodetritus degrading microbial communities in sublittoral Gulf of Mexico sands. Limnology and Oceanography. 54:1073-1083.
  • Winch, S., H.J. Mills, J.E. Kostka, D. Fortin, and D.R.S. Lean. 2009. Identification of sulfate-reducing bacteria in methylmercury contaminated mine tailings by analysis of SSU ribosomal RNA genes. FEMS Microbial Ecology. 68:94-107.
  • Mills, H.J., E. Hunter, M. Humphrys, L. Kerkhof, L. McGuinness, M. Huettel, and J.E. Kostka. 2008. Characterization nitrifying, denitrifying, and overall bacterial communities in permeable marine sediments of the northeastern Gulf of Mexico. Applied and Environmental Microbiology. 74:4440-4453.
  • Akob, D.M., H.J. Mills, T.M. Gihring, L. Kerkhof, J.W. Stucki, A.S. Anastacio, K.-J. Chin, K. Kusel, A.V. Palumbo, D.B. Watson and J.E. Kostka. 2008. Functional diversity and electron donor dependence of microbial populations capable of U(VI) reduction in radionuclide-contaminated subsurface sediments. Applied and Environmental Microbiology. 74:3159-3170.
  • Akob, D, H.J. Mills, and J.E. Kostka. 2007. Metabolically active microbial communities in uranium-contaminated subsurface sediments. FEMS Microbial Ecology. 59:95-107.
  • Burkepile, D., J.D. Parker, C.B. Woodson, H.J. Mills, J. Kubanek, P.A. Sobecky, and M.E. Hay. 2006. Chemically mediated competition between microbes and animals: Microbes as consumers in food webs. Ecology. 87:2821-2831.
  • Hunter, E.M., H.J. Mills, and J.E. Kostka. 2006. Microbial community diversity associated with carbon and nitrogen cycling in permeable shelf sediments. Applied and Environmental Microbiology. 72:5689-5701.
  • Martinez, R., H.J. Mills, S. Story, and P.A. Sobecky. 2006. Prokaryotic diversity and metabolically active microbial populations in sediments from an active mud volcano in the Gulf of Mexico. Environmental Microbiology. 8:1783-1796.
  • Mills, H.J., R. Martinez, S. Story, and P.A. Sobecky. 2005. Characterization of metabolically active microbial populations in Gulf of Mexico shallow gas hydrate. Applied and Environmental Microbiology 71:3235-3247.
  • Mills, H.J., R. Martinez, S. Story and P.A. Sobecky. 2004. Identification of metabolically active populations associated with Beggiatoa sp. mat communities from Gulf of Mexico cold seep sediments. Applied and Environmental Microbiology 70:5447-5458.
  • Mills, H.J., C. Hodges, K. Wilson, I.R. MacDonald and P.A. Sobecky. 2003. Microbial diversity in sediments associated with surface breaching gas hydrate mounds in the Gulf of Mexico. FEMS Microbial Ecology 46:39-52.
  • Powers, L.G., H.J. Mills, A.V. Palumbo, C.L. Zhang, and P.A. Sobecky. 2002. Introduction of a plasmid-encoded phoA gene for constitutive overproduction of alkaline phosphatase in three subsurface Pseudomonas isolates. FEMS Microbiology Ecology 41:115-123.
  • Sobecky P.A., H.J. Mills, K. Beeson and M. Cook. 2002. Marine Plasmids: Insights from diversity studies and sequencing. Proceedings of the International Symposium on Plasmid Biology 2002. Pittsburgh, PA.
  • Mills, H.J., L.G. Powers, A.V. Palumbo, C.L. Zhang, and P.A. Sobecky. 2001. Uranium sequestration by microbially induced phosphorus bioavailability. Proceedings of the In Situ and On-Site Bioremediation Sixth International Symposium. San Diego, CA. June 4-7, 2001


Summer 2012:

-   C-DEBI Activity Theme Team 2012 Workshop. Redondo Beach, CA, August 2012.

-   Science Crew on a one week oceanographic cruise (funded by the NSF – Mills Co-PI) on the R/V Pelican to the Louisiana Shelf, off the coast of LA, August 2012

-   Post-Expedition meeting for Expedition 325. Herron Island, Australia, July, 2012

-   Invited Talk - Mills, H.J. 2012. Highlights from Expedition 336: North Pond Microbiology. IODP-Management International Annual Meeting. Washington, DC. June, 2012

-   Ocean Crust Processes and Consequences for Life Workshop, Bremen, Germany, June, 2012, Break-out group lead. Invited by Dr. Wolfgang Bach, University of Bremen

-   Second International Workshop on Microbial Life Under Extreme Energy Limitation “The Starving Majority.” Aarhus, Denmark. May 2012.

-   Building US Strategies for 2013-2023 Scientific Ocean Drilling. Denver, CO, May, 2012, Break-out group co-leader. Invited by Dr. David Smith, University of Rhode Island


Recent Proposals Funded:

-   NSF – Ocean Drilling Program – Collaborative Research: IODP Expedition 336 Objective Research: The deep biosphere of young and oxic oceanic crust. PI 8/12-7/14

-   Consortium for Ocean Leadership – IODP Workshop Proposal - Joint Meeting with DEBI-RCN IODP Deep Biosphere Research: A synthesis of recent investigations, discussion of new research questions, and identification of new drilling targets. Co-PI 6/12-5/13

-   Consortium for Ocean Leadership – Characterization of the metabolically active fraction of the total microbial community within Expedition 336 North Pond sediment and basalt. PI 3/12-2/14

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