Lost City; carbonate precipitation; lipid biomarkers; compound-specific isotopes; serpentinization; stable isotopes; hydrothermal systems; radiocarbon; microbial activity; volatiles; carbon; organic geochemistry; radiocarbon; IODP
Jaeschke Andrea, Eickmann Benjamin, Lang Susan Q., Bernasconi Stefano M., Strauss Harald, Frueh-Green Gretchen L. (2014), Biosignatures in chimney structures and sediment from the Loki's Castle low-temperature hydrothermal vent field at the Arctic Mid-Ocean Ridge, in
EXTREMOPHILES, 18(3), 545-560.
Morrill Penny L., Brazelton William J., Kohl Lukas, Rietze Amanda, Miles Sarah M., Kavanagh Heidi, Schrenk Matthew O., Ziegler Susan E., Lang Susan Q. (2014), Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN, in
FRONTIERS IN MICROBIOLOGY, 5(Article 61), 1.
Gierga Merle, Schneider Maximilian P. W., Wiedemeier Daniel B., Lang Susan Q., Smittenberg Rienk H., Hajdas Irka, Bernasconi Stefano M., Schmidt Michael W. I. (2014), Purification of fire derived markers for mu g scale isotope analysis (delta C-13, Delta C-14) using high performance liquid chromatography (HPLC), in
ORGANIC GEOCHEMISTRY, 70, 1-9.
Lang Susan Q., Frueh-Green Gretchen L., Bernasconi Stefano M., Wacker Lukas (2013), Isotopic (delta C-13, Delta C-14) analysis of organic acids in marine samples using wet chemical oxidation, in
LIMNOLOGY AND OCEANOGRAPHY-METHODS, 11, 161-175.
Lang Susan Q., Frueh-Green Gretchen L., Bernasconi Stefano M., Wacker Lukas (2013), Isotopic (delta C-13, Delta C-14) analysis of organic acids in marine samples using wet chemical oxidation, in
LIMNOLOGY AND OCEANOGRAPHY-METHODS, 11, 161-175.
Mehay S., Frueh-Green G. L., Lang S. Q., Bernasconi S. M., Brazelton W. J., Schrenk M. O., Schaeffer P., Adam P. (2013), Record of archaeal activity at the serpentinite-hosted Lost City Hydrothermal Field, in
GEOBIOLOGY, 11(6), 570-592.
Schrenk Matthew O., Brazelton William J., Lang Susan Q. (2013), Serpentinization, Carbon, and Deep Life, in
Reviews in Mineralogy CARBON IN EARTH, 75, 575-606.
Schwarzenbach Esther M., Lang Susan Q., Frah-Green Gretchen L., Lilley Marvin D., Bemasconi Stefano M., Mehay Sabine (2013), Sources and cycling of carbon in continental, serpentinite-hosted alkaline springs in the Voltri Massif, Italy, in
LITHOS, 177, 226-244.
Lang S. Q., Frueh-Green G. L., Bernasconi S. M., Butterfield D. A. (2013), Sources of organic nitrogen at the serpentinite-hosted Lost City hydrothermal field, in
GEOBIOLOGY, 11(2), 154-169.
Lang Susan Q., Frueh-Green Gretchen L., Kelley Deborah S., Lilley Marvin D., Proskurowski Giora, Reeves Eoghan P. (2012), H-2/CH4 ratios cannot reliably distinguish abiotic vs. biotic methane in natural hydrothermal systems, in
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 109(47), 3210-3210.
Lang Susan Q., Frueh-Green Gretchen L., Bernasconi Stefano M., Lilley Marvin D., Proskurowski Giora, Mehay Sabine, Butterfield David A. (2012), Microbial utilization of abiogenic carbon and hydrogen in a serpentinite-hosted system, in
GEOCHIMICA ET COSMOCHIMICA ACTA, 92, 82-99.
Lang Susan Q., Bernasconi Stefano M., Frueh-Green Gretchen L. (2012), Stable isotope analysis of organic carbon in small (mu g C) samples and dissolved organic matter using a GasBench preparation device, in
RAPID COMMUNICATIONS IN MASS SPECTROMETRY, 26(1), 9-16.
The project proposed here is a continuation of SNF project No. 200020-131922 and builds on previous organic geochemical and stable isotope studies of geochemical and microbial processes during hydrothermal activity associated with high alkaline fluids in modern serpentinite-carbonate systems. Here we address open questions regarding the production and consumption of dissolved organic carbon (DOC) in marine hydrothermal systems and the links between inorganic reactions and microbial activity that influence biogeochemical cycling of carbon during hydrothermal circulation. The overall goals of the proposed project are to investigate carbon cycles in basalt-hosted and serpentinite-hosted hydrothermal systems with emphasis on sinks and sources of organic compounds and the controls on microbial uptake of carbon from different sources. We will also develop new methods to analyze carbon isotope compositions of organic carbon in marine hydrothermal fluids and lipid biomarkers. Specifically, we address the following major questions: •What processes alter seawater DOC during hydrothermal circulation in basaltic and ultramafic environments with varying thermal structures and fluid pathways? What is the relative contribution of abiotically- versus biotically-derived carbon to DOC concentrations in these hydrothermal systems? •Are oceanic serpentinites an important sink of DOC from seawater, incorporated during fluid-rock interaction? •What controls the microbial uptake of mantle- versus seawater-derived carbon in alkaline hydrothermal systems? Do differences in microbial uptake of mantle C at the Lost City hydrothermal field (Mid-Atlantic Ridge) reflect variations in microbial communities at different sites? Or are the microbial communities largely the same but are able to adapt to changes in environmental conditions and fluid compositions?To address these questions, we will develop novel analytical methods to determine the stable and radiogenic carbon isotope composition of small quantities of carbon in DOC in seawater, in lipid biomarkers, and organic carbon in serpentinites. We will measure radiocarbon contents on organic compounds specific to bacterial (e.g., fatty acids) and archaeal (e.g., PMIs, GDGTs) microbial communities from hydrothermal deposits at Lost City. We will expand forefront analytical techniques that have recently been developed in the Stable Isotope and Organic Geochemistry Laboratory and the Laboratory of Ion Beam Physics at the ETH Zurich. Specifically, the analytical methods involve preparative gas chromatography and high-performance liquid chromatography-mass spectrometry, while radiocarbon contents are measured on the unique Miniaturized Carbon Dating System (MICADAS) equipped with a gas-source, allowing measurements down to a few micrograms of C. The results of this study will provide insight into the fate of organic carbon in marine hydrothermal systems and the relative fluxes of mantle carbon and seawater dissolved inorganic carbon (DIC) to microbial biomass. These are key components of the global carbon cycle that are still poorly constrained.