Back to top

Madsen Lab

Microorganisms in the Real World

My fundamental research interests are in documenting the "who", "what", "how", "where", "when", and "why" of microbiological processes in water, soil, sediments, and ground water. Microorganisms play a critical role in biogeochemical cycling of carbon, nutrients, and pollutant compounds in the biosphere. Yet, methodological limitations of environmental microbiology are severe. For instance, despite its relevance to society, proving that microbial populations are truly active in catalyzing biodegradation of organic pollutants in a given habitat is a difficult task. A synthesis of genetic, biochemical, physiological, analytical, and field-site research will successfully lead to progress in understanding how to measure, verify, and harness microbially-mediated processes that affect environmental quality.

One microbiological process of particular relevance to society is "bioremediation". For "bioremediation" to be transformed from the idea stage into a useful technology, collaboration between many disciplines is essential. In approaching a given contamination scenario, all available methods of pollutant removal and elimination (physical, chemical, microbiological using reactors and in situ techniques) should be considered. When appropriate, application of microbiological processes to eliminating environmental (especially organic) contaminants must follow a logical progression from site characterization and chemical analyses to laboratory and pilot scale verification of process feasibility.

My ongoing research projects have objectives that include characterizing soil and subsurface (ground water) microorganisms and their activities, use of molecular biology in discerning mechanisms of metabolic adaptation to pollutant compounds, understanding geochemical and physiological characteristics which both prevent and foster microbial activity, and developing a rapport with the biogeochemistry of field sites so that realism is an integral part of conceptual advancements in environmental microbiology.

The latest NSF-sponsored research project examines how the biogeochemical cycling of Carbon (biodegradation of organic contaminants) can interact with the cycling of other elements. The key hypothesis of the new project is that as microorganisms oxidize environmental pollutants, they simultaneously cause the accrual of reduced metabolic byproducts, such as Methane, Ammonia, and Sulfide. These, in turn, enrich for microbial populations that carry out new biogeochemical processes that would otherwise be absent from the study site. A major objective of the new project is to discover novel interactions between microbial populations and the processes they catalyze.

Books

Lab Pages