These are all peer-reviewed journal articles published by me and my research group. PDF's are available for download by clicking on the titles; they are for personal use only and may not be redistributed. Files for Talks and Posters or for Other Publications are also available. Scroll down to see everything chronologically, or select a year:
2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2002 2001 1999
2013
◆ Sessions AL, Zhang L, Welander PV, Doughty D, Summons RE, Newman DK (2013) Identification and quantification of polyfunctionalized hopanoids by high temperature gas chromatography-mass spectrometry. Organic Geochemistry 56, 120-130.
◆ Wang Y, Sessions AL, Nielsen RJ, Goddard WA (2013) Equilibrium 2H/1H fractionations in organic molecules: III. Cyclic ketones and hydrocarbons. Geochimica et Cosmochimica Acta 107, 82-95.
◆ Morrill PL, Kuenen JG, Johnson OJ, Suzuki S, Rietze A, Sessions AL, Fogel ML, Nealson KH (2013) Geochemistry and geobiology of a present-day serpentinization site in California: The Cedars. Geochimica et Cosmochimica Acta, in press.
2012
◆ Eiler JM, Clog M, Magyar P, Piasecki A, Sessions AL, Stolper D, Deerberg M, Schlueter H-J, Schwieters J (2012) A high-resolution gas-source isotope ratio mass spectrometer. International Journal of Mass Spectrometry, in press.
◆ Amrani A, Deev A, Sessions AL, Tang Y, Adkins JF, Hill RJ, Moldowan JM, Wei Z (2012) The sulfur-isotopic compositions of benzothiophenes and dibenzothiophenes as a proxy for thermochemical sulfate reduction. Geochimica et Cosmochimica Acta 84, 152-164.
◆ Sachse D, Billault I, Bowen GJ, Chikaraishi Y, Dawson TE, Feakins SJ, Freeman KH, Magill CR, McInerney FA, van der Meer MTJ, Polissar P, Robins RJ, Sachs JP, Schmidt HL, Sessions AL, White JWC, West JB, Kahmen A (2012) Molecular paleohydrology: Interpreting the hydrogen-isotopic composition of lipid biomarkers from photosynthesizing organisms. Annual Reviews of Earth and Planetary Science 40, 221-249.
◆ Ferreira AA, Santos Neto EV, Sessions AL, Schimmelmann A, Aquino Neto FR (2012) 2H/1H ratios of hopanes, tricyclic and tetracyclic terpanes in oils and source rocks from the Potiguar Basin, Brazil. Organic Geochemistry 51, 13-16.
◆ Bontognali TRR, Sessions AL, Allwood AC, Fischer WW, Grotzinger JP, Summons RE, Eiler JM (2012) Sulfur isotopes of organic matter preserved in 3.45-billion-year-old stromatolites reveal microbial metabolism. Proceedings of the National Academy of Sciences 109, 15146-15151.
2011
◆ Doughty DM, Coleman ML, Hunter RC, Sessions AL, Summons RE, and Newman DK (2011) The RND-family transporter, HpnN, is required for hopanoid localization to the outer membrane of Rhodopseudomonas palustris TIE-1. Proceedings of the National Academy of Sciences 108, E1045-E1051.
◆ Bennett SA, Hansman RL, Sessions AL, Nakamura K, and Edwards KJ (2011) Tracing iron-fueled microbial carbon production within the hydrothermal plume at the Loihi seamount. Geochimica et Cosmochimica Acta 75, 5526-5539.
◆ Osburn MR, Sessions AL, Pepe-Ranney C, and Spear JR (2011) Hydrogen-isotopic variability in fatty acids from Yellowstone National Park hot spring microbial communities. Geochimica et Cosmochimica Acta 75, 4830-4845.
◆ Li C, Sessions AL, Thiagarajan N, Valentine D (2011) D/H variations of terrestrial lipids from Santa Barbara Basin over the past 1400 years: A preliminary assessment of paleoclimatic relevance. Organic Geochemistry 42, 15-24.
2010
◆ Feakins SJ and Sessions AL (2010b) Crassulacean acid metabolism influences D/H ratio of leaf wax in succulent plants. Organic Geochemistry41, 1269-1276.
◆ Niedermeyer E, Schefuss E, Sessions AL, Mulitza S, Mollenhauer G, Schulz M, Wefer G (2010) Orbital- and millennial-scale changes in the hydrologic cycle and vegetation in the western African Sahel: insights from individual plant wax δD and δ13C. Quaternary Science Reviews 29, 2996-3005.
◆ Redmond MC, Valentine DL, Sessions AL (2010) Identification of novel methane-, ethane-, and propane-oxidizing bacteria at marine hydrocarbon seeps identified by stable isotope probing. Applied and Environmental Microbiology 76, 6412-6422.
◆ Welander PV, Coleman ML, Sessions AL, Summons RE, Newman DK (2010) Identification of a methylase required for 2-methylhopanoid production and implications for the interpretation of sedimentary hopanes. Proceedings of the National Academy of Sciences 107, 8537-8542.
◆ Li C, Love GD, Lyons TW, Fike DA, Sessions AL, and Chu X (2010) A stratified redox model for the Ediacaran Ocean. Science 328, 80-83.
◆ Feakins SJ and Sessions AL (2010) Controls on the D/H ratios of plant leaf waxes in an arid ecosystem. Geochimica et Cosmochimica Acta 74, 2128-2141.
2009
◆ Amrani A, Sessions AL, Adkins JF (2009) Compound-specific d34S analysis of volatile organics by coupled GC/ICPMS. Analytical Chemistry 81, 9027-9034.
◆ Wang Y, Sessions AL, Nielsen RJ, and Goddard WA (2009) Equilibrium 2H/1H fractionations in organic molecules. I. Experimental calibration of ab initio calculations. Geochimica et Cosmochimica Acta 73, 7060-7075.
◆ Wang Y, Sessions AL, Nielsen RJ, and Goddard WA (2009) Equilibrium 2H/1H fractionations in organic molecules. II. Linear alkanes, alkenes, ketones, carboxylic acids, esters, alcohols and ethers. Geochimica et Cosmochimica Acta 73, 7076-7086.
◆ Marshall AO, Corsetti F, Sessions AL, and Marshall C (2009) Raman spectroscopy and biomarker analysis reveal multiple carbon inputs in a Precambrian glacial sediment. Organic Geochemistry 40, 1115-1123.
◆ Sessions AL, Doughty DM, Welander PV, Summons RE, and Newman DK (2009) The continuing puzzle of the great oxidation event. Current Biology 19, R567-R574.
◆ Welander PV, Hunter RC, Zhang L, Sessions AL, Summons RE, Newman DK (2009) Hopanoids play a role in membrane integrity and pH homeostasis in Rhodopseudomonas palustris TIE-1. Journal of Bacteriology 191, 6145-6156.
◆ Zhang X, Gillespie A, Sessions AL (2009). Large D/H variations in bacterial lipids reflect central metabolic pathways. Proceedings of the National Academy of Science, USA 106(31), 12580-12586.
◆ Li C, Sessions AL, Kinnamen F, Valentine DL (2009). Hydrogen-isotopic variability in lipids from Santa Barbara Basin sediments. Geochimica et Cosmochimica Acta 73, 4803-4823.
◆ Campbell BJ, Li C, Sessions AL, and Valentine DL (2009) Hydrogen isotopic fractionation in lipid biosynthesis by H2-consuming Desulfobacterium autotrophicum. Geochimica et Cosmochimica Acta 73, 2744-2757.
◆ Sauer PE, Schimmelmann A, Sessions AL, and Topalov K (2009). Simplified batch equilibration for D/H determination of non-exchangeable hydrogen in solid organic material. Rapid Communications in Mass Spectrometry 23, 949-956.
2008
◆ Wang Y and Sessions AL (2008).Memory Effects in Compound-Specific D/H Analysis by GC/P/IRMS. Analytical Chemistry 80, 9162-9170.
◆ Jones A, Sessions AL, Campbell BJ, Li C, Valentine DL (2008). D/H ratios of fatty acids from marine particulate organic matter in the California Borderland Basins. Organic Geochemistry 39, 485-500.
◆ Pearson A, Kraunz KS, Sessions AL, Dekas AE, Leavitt WR, Edwards KJ (2008). Quantifying microbial utilization of petroleum hydrocarbons in salt-marsh sediments using the 13C content of bacterial rRNA. Applied and Environmental Microbiology 74, 1157-1166.
2007
◆ Rashby SE, Sessions AL, Summons RE, and Newman DK (2007). Biosynthesis of 2-methylbacteriohopanepolyols by an anoxygenic phototroph. Proceedings of the National Academy of Science 104, 15099-15104.
2006
◆ Eek KM, Sessions AL and Lies DP (2006). Carbon-isotopic analysis of microbial cells sorted by flow cytometry. Geobiology 5, 85-95.
◆ Sessions AL (2006). Isotope-ratio detection for gas chromatography. Journal of Separation Science 29, 1946-1961.
◆ Schimmelmann A, Sessions AL, and Mastalerz M (2006). Hydrogen isotopic (D/H) composition of organic matter during diagenesis and thermal maturation. Annual Reviews of Earth and Planetary Sciences 34, 501-533.
◆ Sessions AL (2006) Seasonal changes in lipid D/H fractionation by Spartina alterniflora. Geochimica et Cosmochimica Acta, 70, 2153-2162.
2005
◆ Olcott AN, Sessions AL, Corsetti FA, Kaufmann AJ, de Olieviera TF (2005) Biomarker evidence for photosynthesis during Neoproterozoic glaciation. Science 310, 471-474.
◆ Sessions AL, Sylva SP and Hayes JM (2005) A moving-wire device for carbon-isotopic analyses of nanogram quantities of nonvolatile organic carbon. Analytical Chemistry 77, 6519-6527.
◆ Sessions AL and Hayes JM (2005) Calculation of hydrogen isotopic fractionations in biogeochemical systems. Geochimica et Cosmochimica Acta 69, 593-597.
2004
◆ McDuffie KE, Eglinton TI, Sessions AL, Sylva SP, Wagner T, and Hayes JM (2004) Rapid analysis of 13C in plant-wax n-alkanes for reconstruction of terrestrial vegetation signals from aquatic sediments. Geochemistry, Geophysics, Geosystems 5, Q10004.
◆ Pearson A, Sessions A L, Edwards KJ, and Hayes JM (2004) Phylogenetically specific separation of rRNA from prokaryotes for isotopic analysis. Marine Chemistry 92, 295-306.
◆ Valentine DL, Sessions AL, Tyler SC, and Chidthaisong, A (2004) Hydrogen isotope fractionation during H2/CO2 acetogenesis: hydrogenase efficiency and the origin of lipid-bound hydrogen. Geobiology 2, 179-188.
◆ Schimmelmann A, Sessions AL, Boreham CJ, Edwards DS, Logan GA, and Summons RE (2004) D/H ratios in terrestrially sourced petroleum systems. Organic Geochemistry 35, 1160-1195.
◆ Sessions AL, Sylva SP, Summons RE, and Hayes JM (2004) Isotopic exchange of carbon-bound hydrogen over geologic timescales. Geochimica et Cosmochimica Acta 68,1545-1559.
◆ Schneider RJ, Kim S-W, von Reden KF, Hayes JM, Wills JSC, Griffin V, Sessions AL, and Sylva SP (2004). A gas ion source for continuous-flow AMS. Nuclear Instruments and Methods in Physics Research (B) 223-224, 149-154
2002
◆ Sessions AL, Jahnke LL, Schimmelmann A, and Hayes JM (2002) Hydrogen isotope fractionation in lipids of the methane-oxidizing bacterium Methylococcus capsulatus. Geochimica et Cosmochimica Acta 66, 3955-3969.
2001
◆ Sauer PE, Eglinton TI, Hayes JM, Schimmelmann A, and Sessions AL (2001) Compound-specific D/H ratios of lipid biomarkers from sediments as a proxy for environmental and climatic conditions. Geochimica et Cosmochimica Acta 65, 213-222.
◆ Sessions AL, Burgoyne TW, and Hayes JM (2001) Correction of H3+ contributions in hydrogen isotope ratio monitoring mass spectrometry. Analytical Chemistry 73, 192-199.
◆ Sessions AL, Burgoyne TW, and Hayes JM (2001) Determination of the H3 Factor in hydrogen isotope ratio monitoring mass spectrometry. Analytical Chemistry 73, 200-207.
1999
◆ Sessions AL, Burgoyne TW, Schimmelmann A, and Hayes JM (1999) Fractionation of hydrogen isotopes in lipid biosynthesis. Organic Geochemistry 30, 1193-1200.
Talks and Posters
This is a selected list of presentations for which PDF files are available. The PDF documents are optimized for viewing on your screen, and may not print well.
Sessions, Alex L (2009) Compound-specific d34S analysis by coupled GC/ICPMS. Poster at the GSA meeting in Portland, OR (file is 1.5 Mb).
Sessions, Alex L (2009) Large variations in lipid D/H ratios associated with microbial heterotrophy. Plenary lecture at the IMOG meeting in Bremen, German (file is 1.2 Mb)
Sessions, Alex L (2008) Huge variations in D/H fractionation associated with microbial heterotrophy. Poster at the 18th annual V.M Goldschmidt Meeting in Vancouver, BC (file is 0.6 Mb)
Sessions, Alex (2007) Hydrogen isotopes in marine lipids. Presentation at the Gordon Conference on Chemical Oceanography, August 2007 (file is 670k)
Sessions, Alex L (2006) Snowball Earth and the Evolution of Animals. Presentation to a general audience at Caltech Alumni Day, May 20, 2006 (file is 1.8 Mb)
Sessions, Alex L (2005) Seasonal variations in D/H fractionation of lipids by Spartina alterniflora. Presentation by ALS at the AGU fall meeting, San Francisco, CA (file is 0.5 Mb)
Sessions, Alex L (2005) Controls on the D/H composition of individual petroleum hydrocarbons. Presentation by ALS at the 15th annual V.M. Goldschmidt Meeting in Moscow, ID (file is 1.6 Mb)
Other Stuff
◆ Coplen, Tyler B. (2011) Guidelines and recommended terms for expression of stable-isotope-ratio and gas-ratio measurement results. Rapid Communications in Mass Spectrometry 25, 2538-2560.
The definitive guideline for nomenclature and definitions related to stable isotopes. The definition of a delta value does not include a factor of 1000...!
◆ Brocks, Jochen J. and Summons, Roger E. (2004) Sedimentary hydrocarbons, biomarkers for early life. Treatise on Geochemistry, volume 8, chapter 3.
This is the most recent and complete review of biomarker information on ancient rocks, and an excellent reference source.
◆ Hayes, John M. (2002) Practice and Principles of Isotopic Measurements in Organic Geochemistry. Electronic version edited by A. Sessions.
Originally published in 1983, I think this is one of the best introductions to the usage of stable isotopes in biogeochemistry. It was updated in 2002 by JMH to include sections on primary standards of stable isotopic abundance, statistical limits on the determination of isotopic ratios, and uncertainties associated with blank-corrected isotope ratios.
◆ Hayes, John M. (2001) Fractionation of the Isotopes of Carbon and Hydrogen in Biosynthetic Processes. Chapter prepared for a short course sponsored by the Mineralogical Society of America and organized by John W. Valley and David R. Cole.
This document contains a comprehensive review of the known isotope effects associated with a variety of biosynthetic pathways.
◆ Sessions, Alex L. (2001) Hydrogen isotope ratios of individual organic compounds. Ph.D. thesis, Indiana University.
Most of this material has appeared in five published research articles. Chapters 4 and 5 contain some additional data on hydrogen exchange and sulfate-reducing bacteria, respectively.