Seasonal patterns of viruses, bacteria and dissolved organic carbon in a riverine wetland

1. Viral and bacterial abundances were studied in relation to environmental attributes over an annual period, for both planktonic and attached (sediment, aquatic macrophyte and submerged wood) habitats, in a riverine wetland. 2. Annual mean abundance of planktonic viruses ranged from 2.3x10(5)-3.8x10(5) particles mL(-1) and varied according to sampling site. Significant seasonal patterns in viral abundance were evident and appeared to be linked to variations in bacterial abundance, dissolved organic carbon and inorganic nutrients. 3. Annual mean abundance of viruses associated with surfaces ranged from 1.3x10(6) particles cm(-2) on aquatic macrophytes to 1.1x10(7) particles cm(-2) on wood and also showed seasonal patterns. The difference in viral dynamics among the different sites emphasizes the importance of considering habitat diversity within wetlands when examining microbial communities.