I am interested in the interface between primary production, microbiology, and biogeochemistry.
A focus of my research is the impact of essential or toxic metal availability in the environment
on primary production, microbial activity, and microbiome interactions. I have developed a new
analytical platform for the discovery and characterization of secreted metal chelators based on
specific high-resolution liquid chromatography-mass spectrometry methods (‘chelomics’) and
applied new electrochemical approaches for metal speciation in natural waters. Among the first
results of the application of chelomics are the isolation and characterization of a new siderophore
class with a unique iron-binding motif and the discovery of a siderophore structure secreted
under anaerobic conditions. We also gained insight into biosynthetic mechanisms for the
secretion of ‘families’ of related siderophore structures, the use of multiple siderophores by one
bacterium, and siderophore secretion in response to metals other than iron as well siderophore
regulation by quorum sensing. My techniques involve profiling, purification, isolation,
characterization, and quantification small-molecules released by plants and microbes. We are
also developing new analytical approaches involving extraction, analysis, and imaging of small
molecules in complex samples matrixes.