Dr Aubrey Zerkle

Reader; Director of Postgraduate Studies

tel: +44 01334 464949
fax: +44 01334 463949
email: az29@st-andrews.ac.uk
room: 423 Irvine (office), D2-D4 Bute (labs)  (Irvine Building)
Irvine Building
University of St Andrews
North Street
St Andrews
KY16 9AL

General Information

I am a biogeochemist and a PI of the Peter James Clark Centre for Philosophical Geobiology. My primary interests are in the early Earth and extraterrestrial environments.

Research in my group focuses on understanding the co-evolution of life with planetary environments over geologic timescales. We utilize a multi-disciplinary approach, including stable isotope geochemistry, microbiology, trace element and nutrient analyses, to examine these interactions and possible feedbacks in modern and paleo-environments. Current research projects revolve around three broad areas:

1.  Investigating feedbacks between the geosphere, atmosphere, and biosphere during important transitions in Earth history, including the Great Oxidation Event, Punctuated Haze Events, and mass extinction events;

2.  Examining biogeochemical cycling in extreme environments that act as modern "analogues" to ancient Earth and exoplanetary systems (e.g., euxinic and acidic environments);

3.  Establishing and evaluating stable isotope biosignatures for microbial activity, on Earth and beyond.


Recent Publications

Mettam, C, Zerkle, AL, Claire, MW, Izon, G, Junium, CJ & Twitchett, RJ 2017, 'High frequency fluctuations in redox conditions during the Late Permian extinction event' Palaeogeography, Palaeoclimatology, Palaeoecology, vol In press. DOI: 10.1016/j.palaeo.2017.06.014
Zerkle, AL & Mikhail, S 2017, 'The geobiological nitrogen cycle: from microbes to the mantle' Geobiology, vol 15, no. 13, pp. 343-352. DOI: 10.1111/gbi.12228
Meyer, NR, Zerkle, AL & Fike, DA 2017, 'Sulphur cycling in a Neoarchean microbial mat' Geobiology, vol 15, no. 13, pp. 353-365. DOI: 10.1111/gbi.12227
Izon, G, Zerkle, AL, Williford, K, Farquhar, J, Poulton, S & Claire, MW 2017, 'Biological regulation of atmospheric chemistry en route to planetary oxygenation' Proceedings of the National Academy of Sciences of the United States of America, vol 114, no. 13, pp. 2571-2579. DOI: 10.1073/pnas.1618798114
Zerkle, AL, Poulton, SW, Newton, RJ, Mettam, C, Claire, MW, Bekker, A & Junium, CK 2017, 'Onset of the aerobic nitrogen cycle during the Great Oxidation Event' Nature, vol 542, pp. 465-467. DOI: 10.1038/nature20826
Zerkle, AL, Jones, D, Farquhar, J & Macalady, J 2016, 'Sulfur isotope values in the sulfidic Frasassi cave system, central Italy: a case study of a chemolithotrophic S-based ecosystem' Geochimica et Cosmochimica Acta, vol 173, pp. 373-386. DOI: 10.1016/j.gca.2015.10.028
Lyons, TW, Fike, DA & Zerkle, AL 2015, 'Emerging biogeochemical views of Earth's ancient microbial worlds' Elements, vol 11, no. 6, pp. 415-421. DOI: 10.2113/gselements.11.6.415
Izon, G, Zerkle, AL, Zhelezinskaya, Y, Farquhar, J, Newton, RJ, Poulton, SW, Eigenbrode, JL & Claire, M 2015, 'Multiple oscillations in Neoarchaean atmospheric chemistry' Earth and Planetary Science Letters, vol 431, pp. 264-273. DOI: 10.1016/j.epsl.2015.09.018
Crowe, SA, Paris, G, Katsev, S, Jones, C, Kim, S-T, Zerkle, AL, Nomosatryo, S, Fowle, DA, Adkins, JF, Sessions, AL, Farquhar, J & Canfield, DE 2014, 'Sulfate was a trace constituent of Archean seawater' Science, vol 346, no. 6210, pp. 735-739. DOI: 10.1126/science.1258966
Farquhar, J, Zerkle, AL & Bekker, A 2014, Geologic and Geochemical Constraints on the Earth's Early Atmosphere. in H Holland & K Turekian (eds), Treatise on Geochemistry: Reference Module in Earth Systems and Environmental Sciences. 2nd edn, vol. 6: The Atmosphere - History, Elsevier, pp. 91-138. DOI: 10.1016/B978-0-08-095975-7.01304-8
Farquhar, J, Cliff, J, Zerkle, AL, Kamyshny, A, Poulton, SW, Claire, M, Adams, D & Harms, B 2013, 'Pathways for Neoarchean pyrite formation constrained by mass-independent sulfur isotopes' Proceedings of the National Academy of Sciences of the United States of America, vol 110, no. 44, pp. 17638-17643. DOI: 10.1073/pnas.1218851110
Oduro, HD, Kamyshny, A, Zerkle, AL, Li, Y & Farquhar, J 2013, 'Quadruple sulfur isotope constraints on the origin and cycling of volatile organic sulfur compounds in a stratified sulfidic lake' Geochimica et Cosmochimica Acta, vol 120, pp. 251-262. DOI: 10.1016/j.gca.2013.06.039
Zerkle, AL, Claire, M, Domagal-Goldman, SD, Farquhar, J & Poulton, SW 2012, 'A bistable organic-rich atmosphere on the Neoarchaean Earth' Nature Geoscience, vol 5, pp. 359-363. DOI: 10.1038/NGEO1425
Zerkle, AL, Scheiderich, K, Maresca, JA, Liermann, LJ & Brantley, SL 2011, 'Molybdenum isotope fractionation by cyanobacterial assimilation during nitrate utilization and N2 fixation' Geobiology, vol 9, no. 1, pp. 94-106. DOI: 10.1111/j.1472-4669.2010.00262.x
Kamyshny, A, Zerkle, A, Mansaray, Z, Ciglenecki, I, Bura-Nakic, E, Farquhar, J & Ferdelman, T 2011, 'Biogeochemical sulfur cycling in the water column of a shallow stratified sea-water lake: Speciation and quadruple sulfur isotope composition' MARINE CHEMISTRY, vol 127, pp. 144-154. DOI: 10.1016/j.marchem.2011.09.001
Farquhar, J, Zerkle, A & Bekker, A 2011, 'Geological constraints on the origin of oxygenic photosynthesis' Photosynthesis Research, vol 107, no. 1, pp. 11-36. DOI: 10.1007/s11120-010-9594-0
Zerkle, AL, Kamyshny, A, Kump, LR, Farquhar, J, Oduro, HD & Arthur, MA 2010, 'Sulfur cycling in a stratified euxinic lake with moderately high sulfate: Constraints from quadruple S isotopes' Geochimica et Cosmochimica Acta, vol 74, no. 17, pp. 4953-4970. DOI: 10.1016/j.gca.2010.06.015
Li, X, Gilhooly, W, Zerkle, AL, Lyons, T, Farquhar, J, Werne, J, Varela, R & Scranton, M 2010, 'Stable sulfur isotopes in the water column of the Cariaco Basin' Geochimica et Cosmochimica Acta, vol 74, pp. 6764-6778.
Anders, M, Fouke, B, Zerkle, AL, Tavarnelli, E, Alvarez, W & Harlow, G 2010, 'The role of calcining and basal fluidization in the long runout of carbonate slides: An example from the Heart Mountain slide block, Wyoming and Montana, USA' The Journal of Geology, vol 118, pp. 577-599.
Canfield, D, Farquhar, J & Zerkle, A 2010, 'High isotope fractionations during sulfate reduction in a low-sulfate euxinic ocean analog' Geology, vol 38, pp. 415-418. DOI: 10.1130/G30723.1
Scheiderich, K, Zerkle, A, Helz, G, Farquhar, J & Walker, R 2010, 'Molybdenum isotope, multiple sulfur isotope, and redox-sensitive element behavior in early Pleistocene Mediterranean sapropels' Chemical Geology, vol 279, pp. 134-144. DOI: 10.1016/j.chemgeo.2010.10.015
Zerkle, AL, Farquhar, J, Johnston, DT, Cox, RP & Canfield, DE 2009, 'Fractionation of multiple sulfur isotopes during phototrophic oxidation of sulfide and elemental sulfur by a green sulfur bacterium' Geochimica et Cosmochimica Acta, vol 73, no. 2, pp. 291-306. DOI: 10.1016/j.gca.2008.10.027
Zerkle, A, Junium, C, Canfield, D & House, C 2008, 'Production of 15N-depleted biomass during cyanobacterial N2-fixation at high Fe concentrations' Journal of Geophysical Research, vol 113. DOI: 10.1029/2007JG000651
Zerkle, AL, House, C, Cox, R & Canfield, D 2006, 'Metal limitation of cyanobacterial N2 fixation and implications for the Precambrian nitrogen cycle' Geobiology, vol 4, pp. 285-297.
Zerkle, AL, House, C & Brantley, S 2005, 'Biogeochemical signatures through time as inferred from whole microbial genomes' American Journal of Science, vol 305, pp. 467-502.
Frias-Lopez, J, Zerkle, AL, Bonheyo, G & Fouke, B 2002, 'Partitioning of bacterial communities between seawater and healthy, black band diseased, and dead coral surfaces' Applied and Environmental Microbiology, vol 68, no. 5, pp. 2214-2228.
Fouke, B, Zerkle, AL, Walter, A, Pope, K, Ocampo, A, Wachtman, R, Grajales Nishimura, J, Claeys, P & Fischer, A 2002, 'Cathodoluminescence petrography and isotope geochemistry of KT impact ejecta deposited 360km from the Chicxulub crater, at Albion Island, Belize' Sedimentology, vol 49, pp. 117-138.

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