Effect of seawater–freshwater cross-transplantations on viral dynamics and bacterial diversity and production

Abstract

Dilution experiments were carried out to investigate the community composition and the metabolic response of seawater and freshwater bacteria to cross-transplantation, and the effects of non-indigenous bacterial hosts on viral dynamics. Changes in viral and bacterial abundance and production, as well as bacterial respiration, carbon demand and diversity were regularly monitored over a 6 d period. Bacterial production in the transplanted seawater (SB-t) and freshwater (FB-t) bacteria treatments was stimulated up to 256 and 221%, respectively, compared to controls. The stimulation of bacterial production and carbon demand was accompanied by a decrease in bacterial richness. Net viral production was stimulated by 81% in SB-t and repressed by 75% in FB-t. Transplantation increased the virus-induced mortality of marine bacteria, but decreased it for freshwater bacteria. These results suggest that (1) marine bacteria can readily oxidize freshwater dissolved organic matter, and (2) freshwater viruses might be able to infect marine hosts, thus highlighting their potential role in fueling bacterial growth under resource stress or nutrient-depleted conditions.

A Vigorous Specialized Microbial Food Web in the Suboxic Waters of a Shallow Subtropical Coastal Lagoon

“…The same pattern is observed in Chesapeake Bay where local bacterioplankton was shown to be diluted by seawater inflow [11]. The reduction of total microbial biomass could consequently stimulate growth of new microorganisms or of those that were being outcompeted before [5,32].…”

Lytic failure in cross-inoculation assays between phages and prokaryotes from three aquatic sites of contrasting salinity

“…2h). The main finding here is that the mixing of viruses and prokaryotes from water of different osmolarity does not always result in a lytic success as was observed by Sano et al (2004) and Bonilla‐Findji et al (2009). However, in this study, planktonic viruses were tested for their ability to move between ecosystems as well as, to a larger extent, their capacity to move between domains of life.…”

Off-site impacts of agricultural composting: role of terrestrially derived organic matter in structuring aquatic microbial communities and their metabolic potential

“…DOC is the largest pool of organic carbon in aquatic ecosystems, and bacteria play an important role in the recycling of this organic matter (del Giorgio & Davis, ). Moreover, shifts in the quantity and quality of DOM can result in changes in bacterial functional and genetic diversity (Bouvier & del Giorgio, ; Rochelle‐Newall et al ., ; Bonilla‐Findji et al ., ; Paver & Kent, ). The results presented here suggest that the application of compost or vermicompost to fields would significantly increase the amount of organic carbon in the leachates from soil.…”