EESS Winter Seminar Series, Sebastian Kopf, Division of Geological & Planetary Sciences, California Institute of Technology
EESS Winter Seminar Series, Sebastian Kopf, Division of Geological & Planetary Sciences, California Institute of Technology, "From lakes to lungs, assessing microbial activity in diverse environments", Abstract: The holy grail of geomicrobiology is to be able to predict how microorganisms respond to changes within an environment. This allows us to interpret the signals of microbial activity that we observe in environments past and present. The main questions that motivate my research towards this goal are to understand how microbes co-evolve with their environments and how we can best study their activity in situ. Here I present work from two environments as examples of this approach. Iron-rich Lake Matano provides a modern analog of the ferruginous Archean oceans. Despite understanding the basic chemistry of this unique environment, the microbial catalysts involved in the biogeochemical cycling of iron are poorly understood. Here, I show how the isolation and characterization of an iron-oxidizing microorganism from this lake led to the discovery of a new pathway for abiotic iron oxidation that suggests a complex interdependence between biological and purely chemical processes involved in the oxidation of iron in anoxic environments. Cystic fibrosis is a genetic disorder that affects the production and accumulation of mucus in a variety of organs. The genetic defect allows for the colonization and chronic infection of patients’ airways by opportunistic pathogens and ranks as the most common lethal genetic disorder in Caucasian populations in the U.S. The development of effective antimicrobial therapies is often hindered by our limited knowledge of the in situ growth conditions that microorganisms experience in this environment. Here, I explore geochemical approaches to studying the microbial ecology using heavy water as a novel isotopic tracer that can provide fundamental insights into microbial growth in cystic fibrosis and any other environment.