Suttle, C.A. and A.M. Chan. 1993. Marine cyanophages infecting oceanic and coastal strains of Synechococcus: abundance, morphology, cross-infectivity and growth characteristics. Marine Ecology Progress Series 92:99-109.
Eight different phycoerythrin- and phycocyanin-containing strains of Synechococcus and one strain of Anacystis were screened against 29 natural virus communities taken from 3 locations in south Texas coastal waters, at different times of the year. In addition, one sample was screened from Peconic Bay, New York. Cyanophages were detected in all samples, but the frequency with which they were detected and their abundance depended upon the strain of Synechococcus that was screened. Viruses that infected red Synechococcus strains were particularly common. In some instances, concentrations infecting a single Synechococcus strain were in excess of 105 ml-1. The abundances of cyanophages were weakly correlated with temperature (r2 = 0.53 to 0.70), although they occurred at all of the temperatures (12-30.4oC) and salinities (18-70 ppt) that were screened. The seven cyanophages that were cloned belonged to the same three families of viruses that have been observed to infect freshwater cyanobacteria, namely the Siphoviridae (formerly Styloviridae), Myoviridae and Podoviridae. The cyanophage clones varied in host-specificity. For example, one clone infected a single Synechococcus strain of 12 that were tested, whereas, another infected 4 of 9 strains tested. Growth characteristics of one of the virus clones was determined for a single host. Photosynthesis in Synechococcus was not affected until near the onset of cell lysis and the virus burst cycle was complete about 17 h post-infection. The burst size was approximately 250 infective particles. The high abundance of cyanophages in the natural environment provides further evidence that viruses are probably important regulators of phytoplankton dynamics in marine systems.