summons roger


Roger Summons’ Geobiology Laboratory focuses on the study of organic matter derived from microbes, environmental samples and sedimentary rocks.  Their ultimate aim is to contribute to knowledge about the history of life on Earth and the evolution of Earth’s surface environment.


Ancient sedimentary rocks and oils contain an abundance of information hidden within fossilized organic matter.   Organic carbon compounds preserve a stunning array of molecular and isotopic signatures for the organisms that existed at the time the organic matter was formed.  The goal of their research is to extract and interpret these signals in order to reconstruct the composition of ancient microbial communities and understand how these communities shaped the Earth as we know it today.  These studies of ancient worlds are grounded on understanding the community composition, biogeochemical cycles and metagenomes that characterize contemporary, microbially-dominated environments.  They also investigate the structures, biosynthetic pathways and physiological function of biomarker lipids.


Particular problems that interest them include the development of oxygenic photosynthesis on the early Earth, the environmental conditions that led to the appearance and radiation of complex multicellular life and the causes and consequences of major mass extinction events.  Related to these issues they are currently investigating ancient and present-day ocean oxygenation and deoxygenation episodes and their relationship to climatic perturbation.


The techniques the lab develops, and signals they study, might eventually help them detect signs of life on other planets as part of their interest in Astrobiology.