Tracing the effect of nutrient and carbon supply on the biosynthesis and composition of lipids from marine microbes

The marine water column and the subsurface sediments remain among the least understood ecosystems on Earth. Particularly, microbial driven processes in marine environment, such as their activity, food-web strategies and ecological function within the marine realm are poorly understood. The aim of the presented research was to expand our knowledge on the microbial community structure and their lipid-based adaption mechanisms to nutrient limitation in the marine realm. To this end pure culture and environmental samples from different regions of the world were investigated using state-of-the-art analytical techniques. This dissertation provides important information on the biosynthesis of microbial lipids under energy limiting conditions, showing that microbes modify their lipid composition according to changing nutrient levels. Moreover, the detailed investigation of the proxy potential of selected microbial lipids, serves important information for future biomarker-based studies. Therefore, this dissertation increased the current knowledge of the microbial community and the physiologic mechanisms of microbes in the marine realm.