Viral ecology of benthic mats from the McMurdo Dry Valleys, Antarctica

Viral abundance was determined for benthic microbial mats collected from the McMurdo Dry Valleys, Antarctica. Virus like particle (VLP) concentrations were high relative to water column of Antarctic Dry Valley lakes and other limnic and pelagic waters worldwide. However, virus to bacteria ratios were much lower than other aquatic habitats, suggesting that viruses may be less important in benthic mats than in planktonic systems. Comparison of viral abundance between moat mat and mat beneath perennial ice, revealed that VLP concentrations in mat collected under-ice were significantly higher than those in moat samples. In three experiments using frozen, live mat, treatment with chemical stresses mitomycin C and copper resulted in increases in VLP several hours after chemical addition, suggesting that lysogenic infection may be an important aspect of mat viral ecology. Finally, an analysis of methods shows that VLP reported are underestimates of virus concentrations present within the Antarctic mat samples.