Research and Teaching Interests
Researchers in my group use chemical concepts and approaches to study geological, chemical and biological processes that shape the Earth’s surface environment and how they have changed through time. Study of these processes teaches us about the habitability of the Earth, the history of the environment and life, the effects of human activities on the environment, and the prospects for life beyond Earth.
Our efforts center on the development and application of novel analytical techniques, particularly using mass spectrometry. Recently, we have been among the pioneers in using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) to precisely measure mass-dependent variations in the isotopic compositions of transition metals, particularly iron and molybdenum. Work by us and others documents that variations of 0.01 – 0.1 %/amu, once undetectable, are actually ubiquitous. Such measurements in natural samples, informed by laboratory experiments and theoretical studies, provide insights into the environmental chemistry of metals and the metal-centered interactions between organisms and their surroundings. Applied to the geologic record, such “metal stable isotope” studies provide information about metal biogeochemical cycles on the ancient Earth, environmental changes that perturbed these cycles, and biological activity in the distant past. A notable recent example of this research is our use of molybdenum isotopes to study changes in the oxygen content of the oceans through time(Arnold et al., 2004).
We plan to continue to explore the biogeochemistry of metals in the middle of the periodic table, using isotopic and other methods. We are especially interested in “metallomic” research that relates the distribution and isotopic composition of metals in nature to the demand for these metals by various metalloenzymes. New state-of-the-art analytical facilities,particularly in the W. M. Keck Foundation Laboratory for Environmental Biogeochemistry, make ASU an exceptional setting to pursue this research.
"Effects of biological soil crusts on soil elemental concentrations: implications for biogeochemistry and as traceable biosignatures of ancient life on land," H. Beraldi-Campesi, H. E. Hartnett, A. D. Anbar, G. W. Gordon and F. Garcia-Pichel, Geobiology 7 348-359 (2009)
"When do black shales tell molybdenum isotope tales?," G. W. Gordon, T. W. Lyons, G. L. Arnold, J. E. Roe, B. B. Sageman and A. D. Anbar , Geology 37 535-538 (2009)
"Tracking euxinia in the ancient ocean: a multiproxy perspective and Proterozoic case study," T. W. Lyons, A. D. Anbar, S. Severmann, C. Scott and B. C. Gill, Ann. Rev. Earth Planet. Sci. 37 507-534 (2009)
"Elemental and iron isotopic composition of aerosols collected in a parking structure," B. J. Majestic, A. D. Anbar and P. Herckes, Sci. Total Env. 407 5104-5109 (2009)
"Isotopic evidence for an aerobic nitrogen cycle in the latest Archean," J. Garvin, R. Buick, A. D. Anbar, G. L. Arnold and A. J. Kaufman, Science 323 1045-1048 (2009)