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Hinrichs Lab - DFG Heisenberg Group - Dr. Gerard Versteegh

DFG-Heisenberg-Group: From biomolecule to geomolecule.

Funding: Deutsche Forschungsgemeinschaft (DFG)
Heisenberg Programme
(Project VE 486/2-1 and VE 486/3-1)
Principal Investigator(s): Gerard Versteegh
Involved scientists in the Hinrichs Lab:  
Partners: Karin Zonneveld, Bremen University
Ian Harding, Univ. Southampton, UK
Armelle Riboulleau, Univ. Lille (USTL), France
Marianne Ellegaard, Univ. Copenhagen, Denmark



The isotopic and molecular formation of kerogen: laboratory, incubation, and natural experiments on recent and fossil organic remains of known biological origin.

Biota are key players in the evolution of the geosphere since the Precambrium and have been driving global biogeochemical cycles of C, N, S, and metals by mediating mineral dissolution and precipitation and catalyzing aqueous redox processes. The composition of sedimentary organic remnants from these ancient biospheres is a direct reflection of this evolution. It also represents by far the largest organic sink in the global carbon cycle. To understand this pool and take advantage of the information it contains, we need to assess the taphonomic processes causing its formation.

Sedimentary organic matter consists predominantly (95%) of kerogen; a poorly understood heterogeneous pool of resistant and complex polymeric bio- and geo- macromolecules, insoluble in common organic solvents. The macromolecular nature of kerogen resists analysis by common chemical techniques. Moreover, other problems are associated with the linking of recorded compounds to biosynthesis, to their source biota in general, and/or differential degradation, alteration and preservation pathways.

Structural elucidation of kerogen has had important consequences for understanding fossilisation processes and consequently formation of oil, gas, and coal and the variability in the cycles of carbon and related elements. Moreover, palaeoenvironmental insights were obtained via the discovery of both new resistant biopolymers and their function in biological systems. Essential to this success has been the linking of distinct morphological recent and fossil botanical, zoological and palynological structures through their bio(geo)chemistry. This enables assessment and comparison of the taphonomic processes transforming recent biomacromolecular structures into their sedimentary counterparts at a molecular level. This can be approached in three mutually supporting ways:
1) Natural kerogen formation on longer time scales (ten to 1 milliard years) by comparing distinct recent and fossil (botanical, zoological) structures and analysing their bio(geo)chemistry. This aims at the structural assessment of recent (cultured) and fossil (from sediments) marine palynomorphs as model compounds of marine kerogen formation and takes advantage of the direct morphological link between the recent organism and its fossil counterpart.

2) Experiments monitoring kerogen formation on short-time scales (0.01 - 10 years). This aims at quantification of the influences of biological, physical and chemical parameters (and their combinations) on kerogen (trans)formation in laboratory and by in situ experiments. Systematic assessment of individual factors influencing kerogen formation is urgently needed to evaluate the natural processes observed, to obtain a mechanistic understanding of taphonomic processes and for modelling degradation kinetics. Experiments at natural conditions as well as elevated pressure and/or temperatures on lipids, macromolecules and their combinations provide a bridge between the transition of short-term and long-term processes.

3) Modelling of kerogen formation and transformation. This aims at identifying gaps and mismatches between theory, experimental results and in situ observations. This not only provides feedback for both projects mentioned above but also leads to a fundamental and quantitative understanding of the kinetic processes and reaction mechanisms involved. Input are the physical, chemical and biological variables influencing degradation dynamics of individual organic compounds alone and in compound mixtures such as redox-potential, oxygen content, pH, temperature, pressure, compound concentration, compound, microbial composition and density, sediment grain size, surface area, mineral composition etc.

Figure: Acquisition of monotypical palynomorph samples prior to chemical analyses, in this case the dinoflagellate cyst Thalassiphora pelagica (Versteegh et al. 2007, Org. Geochem. 38:1643)

Project derived publications:

Boere, A. C., Abbas, B. Rijpstra, W. I., Versteegh, G. J., Volkman, J. K., Sinninghe Damsté, J. S., and Coolen, M. J. (2009) Late-Holocene succession of dinoflagellates in an Antarctic fjord using a multi-proxy approach: paleoenvironmental genomics, lipid biomarkers and palynomorphs. Geobiology, 7, 265-281, doi: 10.1111/j.1472-4669.2009.00202.x.

Dhamelincourt, M. C. Vecoli, M. Mezzetti, A. Cesari, C. Versteegh, G. and Riboulleau, A. (2010) Laser Raman micro-spectroscopy of Proterozoic and Palaeozoic organic-walled microfossils (acritarchs and prasinophytes) from the Ghadamis Basin, Libya and Volta Basin, Ghana. Spectroscopy, 24, 207-212.

Kim, J. H. Huguet, C. Zonneveld, K. A. F., Versteegh, G. J. M. Sinninghe Damsté, J. S. and Schouten, S. (2009) Stability of the TEX86 and UK'37 temperature proxies upon a one year field incubation experiment. Organic Geochemistry 73, 2888-2898.

Versteegh, G. J. M. Zonneveld, K. A. F. and de Lange, G. J. in press. Selective aerobic and anaerobic degradation of lipids and palynomorphs in the Eastern Mediterranean since the onset of sapropel S1 deposition. Marine Geology.

Versteegh, G. J. M., Riboulleau, A., 2010. An organic geochemical perspective on terrestrialisation., in: Vecoli M., Clément G., Meyer-Berthaud B. (eds.), The Terrestrialisation Process: Modelling Complex Interactions at the Biosphere - Geosphere Interface, Geological Society of London Special Publications 339 pp. 11-36.

Zonneveld, K. A. F. Versteegh, G. J. M. Kasten, S. Eglinton, T. I. Emeis, K. C. Huguet, C. Koch, B. P. de Lange, G. J. de Leeuw, J. W. Middelburg, J. J. Mollenhauer, G. Prahl, F. G. Rethemeyer, J. and Wakeham, S. G., 2010. Selective preservation of organic matter in marine sediments - processes and impact on the fossil record. Biogeosciences 7, 483-511.

Zonneveld, K. A. F. Versteegh, G. J. M. and Kodrans-Nsiah, M., 2008. Preservation and organic chemistry of Late Cenozoic organic-walled dinoflagellate cysts: A review. Marine Micropaleontology 86, 179-197.