Virioplankton: Viruses in Aquatic Ecosystems

Abstract

SUMMARY The discovery that viruses may be the most abundant organisms in natural waters, surpassing the number of bacteria by an order of magnitude, has inspired a resurgence of interest in viruses in the aquatic environment. Surprisingly little was known of the interaction of viruses and their hosts in nature. In the decade since the reports of extraordinarily large virus populations were published, enumeration of viruses in aquatic environments has demonstrated that the virioplankton are dynamic components of the plankton, changing dramatically in number with geographical location and season. The evidence to date suggests that virioplankton communities are composed principally of bacteriophages and, to a lesser extent, eukaryotic algal viruses. The influence of viral infection and lysis on bacterial and phytoplankton host communities was measurable after new methods were developed and prior knowledge of bacteriophage biology was incorporated into concepts of parasite and host community interactions. The new methods have yielded data showing that viral infection can have a significant impact on bacteria and unicellular algae populations and supporting the hypothesis that viruses play a significant role in microbial food webs. Besides predation limiting bacteria and phytoplankton populations, the specific nature of virus-host interaction raises the intriguing possibility that viral infection influences the structure and diversity of aquatic microbial communities. Novel applications of molecular genetic techniques have provided good evidence that viral infection can significantly influence the composition and diversity of aquatic microbial communities.

Re-examination of the relationship between marine virus and microbial cell abundances

“…Wommack and Colwell [57] 2000 A VBR "roughly equal to 10" (attributed to Maranger and Bird [31] is designated as a target for parameterizing the Kill-the-Winner theory of virus-microbe interactions.…”

Mixing alters the lytic activity of viruses in the dark ocean

“…This notion is underlined by the finding that prokaryotic leucine incorporation rates often are positively correlated with prokaryotic and viral abundance (Wommack and Colwell 2000, this study see Results section and Table 1), allowing interpreting these parameters as a proxy for productivity. Statistical analyses revealed that changes in FIC and VP relative to the controls could largely be explained by how strongly the source water masses differed in their level of productivity (Fig.…”

“…1998, De Paepe and Taddei 2006) and consequently also among aquatic environments (Wommack and Colwell 2000, Weinbauer 2004, Parada et al. 2006) harboring different viral communities.…”

“…Additionally, differences in trophic conditions have been implicated to alter the percentage of lysogenically infected prokaryotic cells at the surface (Williamson and Paul 2004, 2006). Thus, prokaryotic leucine incorporation as a measure for prokaryotic heterotrophic activity together with prokaryotic and viral abundance were used as a proxy for the trophic conditions of the parent water masses (Wommack and Colwell 2000, Finke et al. 2017).…”

Biome engineering‐2020

“…Since bacterial viruses (‘bacteriophages’) represent the greatest share of the gut virome and since lytic phages only survive via infection and lysis of their bacterial target cells, phages need to be integrated into a comprehensive description if we want to understand the ecological functioning of the gut microbiome. It will be interesting to see whether concepts developed by marine microbial ecologists like ‘killing the winning population’ (Wommack and Colwell, 2000) also apply to the gut or whether alternative concepts putting more emphasis on temperate phages are more relevant for the gut (Knowles et al ., 2016). For the next years, interesting insights can be expected from this field which will introduce new dynamic and mechanistic aspects into a gut microbiota research and its modulation.…”