Rodda, K., L. Clark, E. Ingall and C.A. Suttle. 1996. Infective cyanophages persist in anoxic sediments on the continental shelf of the Gulf of Mexico. Eos 76(3 suppl):OS207.

The occurrence and abundance of cyanophages which infect Synechococcus sp. strain DC2 were measured in the sediments and overlying water at a shelf site in the northwestern Gulf of Mexico. Cyanophage titer in the water column ranged from 1.4 x 105 mL-1 at the surface to 1.0 x 104 mL-1 at a bottom depth of 46.6 meters. In the sediment interstitial water the cyanophage titer decreased rapidly from 1.5 x 105 mL-1 at the water-sediment interface to ca. 2.0 x 103 mL-1 at 4 cm. This sudden decrease was associated with the redox boundary as indicated by the disappearance of nitrate and the appearance of high concentrations of pore water iron. Below the redox boundary infective cyanophage concentrations persisted, and were present at ca. 3.0x102 mL-1 at 30 cm below the sediment surface, the deepest sample taken on the cores. These results indicate that infective cyanophages can persist in anoxic pore waters. Moreover, pore water profiles of dissolved phosphate, iron, silicate, and flouride suggest that irrigation is not a significant source of nutrient dispersal below 10 cm into the sediment, suggesting that infective cyanophages and possibly other viruses can persist at depth in marine sediments for extended periods. These sediments could serve as a reservoir of infectious viruses.

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