Albert S. Colman
Email: asc25 at uchicago.edu
Office #: HGS 321
Research interests: Stable isotope biogeochemistry and GeomicrobiologyMy current research covers an array of topics in biogeochemistry that share a common theme. These projects address important uncertainties in our understanding of global biogeochemical cycles and paleoenvironmental conditions.
The overarching questions:
(a) How do authigenic and biogenic minerals and sedimentary rocks acquire compositions, both isotopic and elemental, that record their temperatures of formation and/or the chemistry of the solutions in which they form?
(b) Under what diagenetic and metamorphic conditions are these diagnostic compositions preserved, and under what conditions are they overprinted?
(c) What do appropriately chosen samples tell us about paleoenvironmental conditions as well as modern day biogeochemistry?
(d) What are the atomic scale and global scale controls on the rates of mineral precipitation and dissolution for minerals that exert significant control (as nutrients, redox capacitors, CO2 and O2 sinks/sources, etc.) on important global cycles?
Microbes play a central role in many of the mineral precipitation, alteration, and dissolution processes indicated above. Stable isotopes of carbon, nitrogen, oxygen, hydrogen, and sulfur are sensitive indicators of microbial and abiological processes. I am establishing a center for stable isotope mass spectrometry and geomicrobiology to tackle the above questions.
The major individual research topics:
(1) Oxygen isotope composition of dissolved phosphate in aquatic ecoystems as a tool for understanding phosphorus biogeochemistry;
(2) Microbial ecology and microbe-mineral interactions in thermophilic mats of Uzon Caldera, Kamchatka;
(3) Carbon monoxide as a metabolic intermediate in anaerobic microbial mats;
(4) Phosphorus dynamics during early diagenesis and redox feedbacks on ocean productivity and atmospheric composition;
(5) Pyrite suns, anaerobic methane oxidation, and ancient sea water composition;
(6) Preservation of paleotemperature signals (δ18O of phosphate) in biogenic apatite;
(7) Phosphate δ18O systematics of microbial ecosystems in Lost City hydrothermal vents.
Mohamed, NM, AS Colman, Y Tal, RT Hill (2008). Diversity and expression of nitrogen fixation genes in bacterial symbionts of marine sponges. Envir. Microbiology, in press.
Colman, AS, SM Techtmann, FT Robb (2008). Carbon monoxide and the chemolithoautotrophic potential of Early Earth and Mars. For submission to Geophysical Research Letters, in preparation.
Terwilliger, V.J., Z. Eshetu, A.S. Colman, T. Bekele, A. Gezahgne, and M.L. Fogel (2008) Reconstructing palaeoclimate and land use from δ13C and δ15N values of soil organic matter: a test using arid and wetter elevation transects in Ethiopia. In review, Geoderma..
Colman, A.S., R.E. Blake, D.M. Karl, R.W. Wildman, B.P. Colman, and M.L. Fogel (2008) Method for measuring the oxygen isotope composition of phosphate in seawater, fresh water, and waste water treatment plant effluent. For submission to Analytical Chemistry, in preparation.
Wiedemann-Bidlack, F.B., A.S. Colman, and M.L. Fogel (2008). Stable isotope analyses of phosphate oxygen from biological apatite: a new technique for microsampling, microprecipitation of Ag3PO4, and removal of organic contamination. Rapid Commun. Mass Spectrom., 22, 1807-1816.
Reid, I.N., W.B. Sparks, S. Lubow, M. McGrath, M. Livio, J. Valenti, K.R. Sowers, H.D. Shukla, S. MacAuley, T. Miller, R. Suvanasuthi, R. Belas, A. Colman , F.T. Robb, P. DasSarma, J.A. Müller, J.A. Coker, R. Cavicchioli, F. Chen & S. DasSarma. (2006) Terrestrial models for extraterrestrial life: methanogens and halophiles at Martian temperatures, Int. Jour. Astrobiology, 5, 10.1017/S1473550406002916.
Colman, A.S., R.E. Blake, D.M. Karl, M.L. Fogel, and K.K. Turekian (2005). Marine biogeochemistry as revealed through the oxygen isotope composition of phosphate. Proc. Nat. Acad. Sci., 102, 13023-13028.
Colman, A.S. (2002). The oxygen isotope composition of dissolved inorganic phosphate and the marine phosphorus cycle. PhD Dissertation, Yale University.
Vennemann, T.W., H.C. Fricke, R.E. Blake, J.R. O'Neil, and A. Colman (2002). Oxygen isotope analysis of phosphates: a comparison of techniques for analysis of Ag3PO4. Chem. Geol., 185, 321-336.
Colman, A.S. and H.D. Holland (2000). The global diagenetic flux of phosphorus from marine sediments to the oceans: redox sensitivity and the control of atmospheric oxygen levels. in Marine Authigenesis: from Global to Microbial, Eds. C.R. Glenn, J. Lucas, and L. Prévôt-Lucas. SEPM Spec. Pub. No. 66, pp. 53-75.
Munger, J.W., D.J. Jacob, S.-M. Fan, A.S. Colman, J.E. Dibb (1999). Concentrations and snow-atmosphere fluxes of reactive nitrogen at Summit, Greenland. J. Geophysical Research,104, 13721-13734.
Munger, J.W., S.-M. Fan, P.S. Bakwin, M.L. Goulden, A.H. Goldstein, A.S. Colman, and S.C. Wofsy (1998). Regional budgets for nitrogen oxides from continental sources: variations of rates for oxidation and deposition with season and distance from source regions. J. Geophysical Research, 103, 8355-8368.
Colman, A.S., F.T. Mackenzie, and H.D. Holland; reply by P. Van Cappellen and E.D. Ingall (1997). Redox stabilization of the atmosphere and oceans and marine productivity. Science, 275, 406-408.
Munger, J.W., S.-M. Fan, A.S. Colman, I.R. Mendelson, and D.J. Jacob (1995). Eddy correlation measurements of snow-atmosphere exchange of NOy and H2O at Summit, Greenland. Arctic Research of the U.S.
Courses:23805. Stable Isotope Biogeochemistry. PQ: CHEM 11100-11200-11300 or
equivalent; GEOS 13100-13200-13300 or consent of instructor. Stable isotopes of H, C,
O, N, and S are valuable tools for understanding the biological and geochemical
processes that have shaped the composition of Earth's atmosphere and oceans
throughout our planet's history. This course examines basic thermodynamic and
kinetic theory to describe the behavior of isotopes in chemical and biological
systems. We then examine the stable isotope systematics of localized environmental
processes, and see how local processes contribute to global isotopic signals that
are preserved in ice, sediment, rock, and fossils. Special emphasis is placed on the
global carbon cycle, the history of atmospheric oxygen levels, and paleoclimate.
A. Colman. Winter.
23900. Environmental Chemistry. (=ENST 23900) PQ: CHEM 11101-
11201 or equivalent, and prior calculus course. The focus of this course is the
fundamental science underlying issues of local and regional scale pollution. In
particular, the lifetimes of important pollutants in the air, water, and soils are
examined by considering the roles played by photochemistry, surface chemistry,
biological processes, and dispersal into the surrounding environment. Specific
topics include urban air quality, water quality, long-lived organic toxins, heavy
metals, and indoor air pollution. Control measures are also considered. D. Archer,
A. Colman. Autumn. L.