Cover photograph (Copyright © 2007, American Society for Microbiology. All Rights Reserved.): Springtime view of snowcovered blocks of melting sea ice in a coastal area of Ellesmere Island in the Canadian high-Arctic archipelago. In polar areas, these seemingly pristine environments are contaminated by globally distributed anthropogenic pollutants, such as mercury. Microbes, previously described as inhabiting polar environments, have the potential to affect the toxicity and environmental mobility of mercury in these regions. Indeed, diverse merA genes and their transcripts, specifying mercury reduction to the volatile elemental form, were found in microbial biomass of coastal lagoons and among epiphytes of marine macroalgae. Photo by B. E. Keatley. (See related article in the April 2007 issue: volume 73, page 2230.)