Dr Richard Pancost, BS (Hons) PhD
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Background
In 1992, I obtained my B.S. degree in Geology (with high honors) from Case Western Reserve University (Cleveland, USA) and began my Ph.D. research with Dr. Katherine Freeman at the Pennsylvania State University. There, I conducted research on environmental and physiological controls on the carbon isotopic composition of free and bound biomarker compounds in modern surface-water samples of the Peru upwelling region and ancient sediments of the Cretaceous Western Interior Seaway (Cenomanian-Turonian boundary) and Taconic foreland basin (Late Ordovician). The common theme of these diverse studies was the development and application of compound-specific carbon isotope analysis as a tool to reconstruct ancient changes in p2 and organic matter inputs to sedimentary basins. As a research assistant I either conducted or assisted with similar studies on waters from the equatorial Pacific and Sargasso Sea and sediments from the Congo Basin (Jurassic) and German Kellwasser horizons (end-Devonian OAE).
Upon completion of my Ph.D. in 1998, I accepted a post-doctoral fellowship with Dr. J. S. Sinninghe Damsté at the Netherlands Institute for Sea Research, where I was responsible for the maintenance and utilization of mass spectrometry instrumentation. Research conducted by myself in this capacity included examinations of chemically unique kerogens associated with the Kimmeridge Clay Formation and the use of carbon isotopes as tracers of microbial processes, specifically the anaerobic oxidation of methane by a consortia of archaea and sulphate-reducing bacteria in marine sediments. In addition, I served as an advisor on Ph.D. projects that involved extensive isotopic analyses, including investigations of Tethyan palaeoceanography during the Cenomanian-Turonian OAE and controls on the isotopic composition of biomarkers in Kyllaren fjord sediments.
On August 1, 2000 I began a permanent lecturer position in the School of Chemistry (Organic Geochemisty Unit and Biogeochemistry Research Centre) at the University of Bristol.
Research
Proxies for Paleoclimate Reconstruction
Organic matter preserved in ancient marine, lacustrine, and peat deposits are vast repositories of information on Earth’s climate through time. Biomarkers provide insight into the organisms living in the past, and the environmental conditions necessary for such organisms to thrive can then be elucidated. Further information is provided by the isotopic compositions of such biomarkers. Because δ13C and δD values of biomass are governed by environmental conditions, compound-specific isotope proxies can be used to reconstruct ancient pCO2 levels, rainfall, temperature, food web structure, and methane cycling. Our research focuses on the development and refinement of such proxies by using cultures and field samples to identify diagnostic compounds and the controls on their isotopic compositions. We are also engaged in research that applies those techniques to specific problems in Earth history, including mass extinctions, the transition into and out of greenhouse climates, and the evolution of life.
Geomicrobiology
Bacteria and Archaea comprise two of the three Domains of life and are essentially ubiquitous on the Earth’s surface. Recent developments in genetic techniques have reinvigorated the field of geomicrobiology by prompting new discoveries and reaffirming the importance of microbes in biogeochemical processes. At the same time, new analytical chemistry techniques now allow direct contributions to microbiology from molecular biogeochemists, particularly when novel biomarkers are integrated with isotopic determinations. Our work in this area includes studies of the microbiology of CO2 and methane cycling in peat deposits and the role of archaea in anaerobic methane oxidation. We also study the archaea and bacteria present in extreme environments, such as hydrothermal vents and deep-sea brine lakes. Interest in extreme settings arises from the potential that extremophiles could generate medicinal compounds and the prevailing impression that such settings represent good models for life on the early Earth.
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Photo of a cold seep where biomarkers have been used to identify AOM. Note extensive crusts and tube worms, both present due to AOM; photo taken from the submersible Nautile during the MEDINAUT Project. |
Preservation of Organic Matter
The preservation of organic matter is a topic of much interest to a range of scientists: it is critical to the formation of fossil fuel deposits, has important implications for the global carbon cycle and is an essential process in the preservation of organic materials in the fossil record. Our research focuses on both the types of environmental conditions in the past that would have favoured extensive organic matter burial and preservation (e.g. oceanic anoxic events) as well as the chemical transformation of biological organic matter into kerogen. This latter process is of much interest as it is still unclear from where the aliphatic signature of most sedimentary organic matter derives. However, recent work in our group suggests that organic materials previously thought to be relatively labile, including lipids, could be bound into resistant ‘geomacromolecules’, playing an important role in organic matter preservation and governing its chemical structure.
Publications
A full list of my publications is available here.