A Berkeley Lab team analyzed the genotypes and phenotypes of several Arthrobacter strains to correlate cellular functions to their location at varying depths within a single sediment core and in nearby groundwater. They found that Arthrobacter, as a genus, has remarkable flexibility in altering its suites of carbon degradation genes. This genomic variation was found to be linked to the individual strain’s environment and is the basis for Arthrobacter’s ability to break down a wide variety of complex carbon sources.