DFG-funded project BIHYS (SE 682/8-1): Biosignatures in precipitates and altered rocks at hydrothermal systems of the Mid-Atlantic Ridge: organic geochemistry, microbiology and petrography

Principal investigators and Co-PIs:

Dr. Richard Seifert (IfBM, University of Hamburg)
Dr. Martin Blumenberg (Geoscience Centre, Göttingen)
Dr. Sven Petersen (IFM-GEOMAR Kiel)
Dr. Mirjam Perner (Biocenter, Univ. Hamburg)

Summary of the project

Over the past few years it has been shown that hydrothermal systems on the modern ocean floor contain a substantial microbial community based on the supply of energy and nutrients from water rock interaction and that they may thrive in the subseafloor to greater depth. It has also become evident that these life forms have a substantial but underestimated part in whole rock alteration, formation of massive sulphides on the seafloor and the geochemical exchange between the lithosphere and the ocean. At mid-ocean ridges the chemical energy is primarily supplied by the hot vent fluids that are the product of water/rock interaction at high temperatures within the oceanic crust. These fluids are rich in reduced chemical compounds such as H2S, H2 and CH4 as well as reduced forms of metals such as Fe that can be used to sustain life. Calculations have shown that oxidation of elemental sulphur and metal sulphides in the hydrothermal plume represents at least 40% of the total metabolic energy available for chemolithoautotrophic growth. The proposed study aims at gaining insight into the chemolithoautotrophic life associated to hydrothermal precipitates and rocks by combining the information from detailed organic geochemical, microbiological, and mineralogical/petrographical investigations on identical samples. Three goals are in focus: (i) to describe the composition and specific biomarker inventory of the microbial community present in hydrothermal precipitates and altered rocks; (ii) to relate these findings to the characteristics of the substrate (mineral assemblage, geochemistry, porosity) (iii) to obtain insight into the metabolism of rock associates and their possible effect on precipitation – alteration - weathering. It is envisaged to develop an inventory of lipid biomarkers characteristic of the distinct groups of microbiota by investigation of field samples from a variety of hydrothermal areas along the MAR and invitro cultures. Thus, a tool is to be established allowing for a qualitative and semi-quantitative estimation of microbial associations in hydrothermal rocks by lipid biomarker investigation combined with compound specific analysis of stable isotope signatures.

contact:

Dr. Martin Blumenberg (Tel.: +49(0)551-39-13756)
martin.blumenberg@geo.uni-goettingen.de
Dr. Richard Seifert (Tel: +49(0)40-42838-4987)

Foto: Quest  Marum Team, Bremen Black Smoker

For futher details see

Blumenberg, M. Petersen, S., Michaelis, W., and Seifert R. (2007) Biosignatures present in a hydrothermal massive sulfide from the Mid-Atlantic Ridge. Geobiology 5, 435-450.

Perner, M., Seifert, R., Weber, S., Koschinsky, A., Schmidt, K., Strauss, H., Peters, M., Haase, K., Imhoff, J.F., (2007) Microbial CO2 fixation and sulfur cycling associated with low-temperature emissions at the Lilliput hydrothermal field, southern Mid-Atlantic Ridge (9°S). Environ. Microbiol. 9, 1186-1201.