High abundance of viruses found in aquatic environments

  title={High abundance of viruses found in aquatic environments},
  author={{\O}ivind Bergh and Knut Yngve B{\O}rsheim and Gunnar Bratbak and Mikal Heldal},
THE concentration of bacteriophages in natural unpolluted waters is in general believed to be low1,2, and they have therefore been considered ecologically unimportant3. Using a new method for quantitative enumeration, we have found up to 2.5 x IO8 virus particles per millilitre in natural waters. These concentrations indicate that virus infection may be an important factor in the ecological control of planktonic micro-organisms, and that viruses might mediate genetic exchange among bacteria in… 
[Molecular ecology of microalgal viruses].
It is elucidating that viral infection is one of the most important factors determining the dynamics and termination of algal blooms by means of field survey and molecular experiments and demonstrated that the interrelationship between viruses and their hosts are highly complicated, and might be determined by the molecular-structural difference of viral capsids among distinct virus ecotypes.
Production and decay of viruses in aquatic environments
It is found that phages may be a major cause of bacterial mortality in aquatic ecosystems and may have a significant impact on the carbon and nutrient flow in aquatic food webs.
Significance of bacteriophages for controlling bacterioplankton growth in a mesotrophic lake
The cyclic dynamics between bacteria and phages and the varying size structure of the intracellular mature phage particles suggested that phage infection was important in structuring the bacterial host assemblage during the study period.
Infection of phytoplankton by viruses and reduction of primary productivity
It is demonstrated that viral pathogens infect a variety of important marine primary producers, including diatoms, cryptophytes, prasinophytes and chroococcoid cyanobacteria, indicating that infection by viruses could be a factor regulating phytoplankton community structure and primary productivity in the oceans.
Three-year survey of abundance, prevalence and genetic diversity of chlorovirus populations in a small urban lake
Examination of water samples for the abundance, prevalence, and genetic diversity of a group of infectious viruses (chloroviruses) that infect symbiotic chlorella-like green algae suggests their impact as key factors in shaping microbial community structures in the water surface.
Preliminary observations on the concentration of marine bacteriophages in the water around Helgoland
  • K. Moebus
  • Environmental Science
    Helgoländer Meeresuntersuchungen
  • 2006
In a preliminary survey, conducted between August 28 and October 9, 1990, the concentration of bacteriophages in seawater sampled at intervals of 1 to 4 days near Helgoland (station Kabeltonne) was
Ecology of bacteriophages infecting activated sludge bacteria
The results show that phages are an active part of this ecosystem and that they may exert selection pressure for phage resistance on their bacterial host populations.
Viruses and the microbial loop
Few studies have been carried out, but viruses appear to have a significant impact on carbon and nutrient flow in microbial food webs and to exert a species specific control of both bacteria and phytoplankton populations in natural waters.
In Situ Population Dynamics of Bacterial Viruses in a Terrestrial Environment
In situ population dynamics of three separate phage populations predating on separate bacterial species, living on the surface of field-grown sugar beet (Beta vulgaris var Amethyst), as recorded over a 9-month period are described.


Rate of Bacterial Mortality in Aquatic Environments
Results obtained from river water, estuarine water, and seawater show overall bacterial mortality rates in the range 0.010 to 0.030 h, in good agreement with the range of growth rates measured in the same environments.
Do Bacteria-Sized Marine Eukaryotes Consume Significant Bacterial Production?
Evidence is presented that previously uncharacterized, small eukaryotes that are able to pass even 0.6-micrometer filters may be responsible for a large fraction of the total grazing in coastal waters.
Minimum bacterial density for bacteriophage replication: implications for significance of bacteriophages in natural ecosystems
It is suggested that bacteriophages do not affect the number or activity of bacteria in environments where the density of the host species is below the host cell threshold of about 10(4) CFU/ml.