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Mareike Neumann


+49 421 218-65824


IW-3, room 1280

Mareike Neumann

Max Planck Institute for Biogeochemistry, Jena


PhD project

From green algae to land plants: The diversification of the stigmasteroid biosynthetic pathway throughout the early Paleozoic

Plants play a major role in global ecology: they provide oxygen for the atmosphere, contribute nutrients through the weathering of rocks and are the base of the terrestrial trophic food chain. First evidence for land plants comes from fossil spores that date back to the mid-Ordovician. It took plants several significant evolutionary innovations to adapt to the terrestrial habitat, where they had to overcome obstacles such as potential water shortages, higher exposure to radiation, extreme weather or wind.

Not only the morphological adaptations to conditions on land are what distinguishes land plants from their ancestors, the green algae, but also a small but significant difference occurs on the molecular level. Organisms of the green lineage, namely green algae and land plants, synthesize sterols with 29 carbon atoms, e.g. stigmasteroids. The structural geometry of these molecules provides the possibility for two different orientations of some of these carbon atoms, especially in the sterol side chain.  While green algae prefer one orientation, land plants have a higher affinity towards the other stereochemical setup.

In my project I will study the biomarker (molecular fossil) composition in a set of oil and outcrop samples from different early Paleozoic basins by applying standard methods from the field of organic geochemistry. My aim is to (1) develop a method for the separation of the stereochemically different biomarkers for green algae and land plants and (2) trace the emergence and diversification of the land plant biosynthetic pathway, potentially even before we see evidence of them in the fossil record.

Thesis committee

Dr. Christian Hallmann Max Planck Institute for Biogeochemistry, Jena and MARUM - Center for Marine Environmental Sciences, University of Bremen
Prof. Dr. Malgorzata Moczydlowska University of Uppsala, Sweden
Prof. Dr. Thomas Servais University of Lille, France
PD Dr. Karin Zonneveld University of Bremen


GLOMAR Research Theme C