Virioplankton community structure along a salinity gradient in a solar saltern

摘要

The virioplankton community structure along a salinity gradient from near seawater (40‰) to saturated sodium chloride brine (370‰) in a solar saltern was investigated by pulsed-field gel electrophoresis. Viral populations with genome sizes varying from 10 kb to 533 kb were detected. The viral community structure changed along the salinity gradient. Cluster analysis of the viral genome-banding pattern resulted in two main clusters. The virioplankton diversity within the samples with salinity from 40‰ to 150‰ was on the same cluster of a cladogram. The other group consisted of virioplankton from samples with salinity above 220‰. The virioplankton diversity in the different samples was calculated using the Shannon index. The diversity index demonstrated an increase in diversity in the samples along the gradient from 40‰ to 150‰ salinity, followed by a decrease in the diversity index along the rest of the salinity gradient. These results demonstrate how viral diversity changes from habitats that are considered one of the most common (seawater) to habitats that are extreme in salt concentrations (saturated sodium brine). The diversity index was highest in the environments that lie in between the most extreme and the most common.