Viral shunt

Definition

Viral shunt refers to the process by which marine viruses infect and lyse phytoplankton and other microorganisms, leading to the release of dissolved organic matter (DOM) into the surrounding water. This process plays a crucial role in the marine ecosystem by influencing nutrient cycling and energy flow. As viruses attack and destroy host cells, they redirect carbon and nutrients that would have been utilized by the microorganisms, thus affecting food webs and biogeochemical cycles.

5 Must Know Facts For Your Next Test

1. Viral shunt can lead to significant changes in community composition of phytoplankton, as viral infections preferentially target certain species over others.
2. By increasing the amount of DOM in the water, viral shunt can enhance bacterial growth, which may support a larger microbial community and influence nutrient cycling.
3. The efficiency of viral shunt can vary depending on environmental conditions such as temperature, nutrient availability, and community composition.
4. Viral shunt is an important mechanism for regulating primary production in marine environments, impacting overall productivity and biomass accumulation.
5. The release of nutrients from lysed cells through viral shunt can stimulate secondary production, benefiting higher trophic levels including zooplankton and fish.

Review Questions

• How does viral shunt affect the dynamics of marine microbial communities?
  • Viral shunt impacts marine microbial communities by selectively infecting and lysing phytoplankton species, which leads to shifts in community composition. This selective predation can favor less susceptible species or promote the growth of bacterial populations that utilize the released DOM. Consequently, it alters nutrient cycling and influences the overall productivity of the marine ecosystem.
• Discuss the implications of viral shunt on nutrient cycling in marine ecosystems.
  • Viral shunt significantly alters nutrient cycling by releasing dissolved organic matter into the water column when viruses lyse phytoplankton. This DOM becomes available for bacterial consumption, enhancing their growth and contributing to nutrient regeneration. Such processes are vital for maintaining productivity within marine ecosystems, as they facilitate a continuous flow of energy and nutrients through food webs.
• Evaluate the role of viral shunt in shaping the structure and function of marine food webs.
  • Viral shunt plays a critical role in shaping marine food webs by affecting primary production and influencing community dynamics among phytoplankton and bacteria. By diverting carbon away from higher trophic levels and promoting bacterial growth through increased DOM availability, viral shunt modifies energy flow within these ecosystems. The cascading effects on zooplankton populations and fish ultimately reflect how viral interactions can impact biodiversity and ecosystem resilience in marine environments.

Related terms

Dissolved Organic Matter (DOM): Organic compounds that are dissolved in water, which can be derived from the breakdown of organic material by microbial activity, including the release from lysed cells.

Microbial Loop: The pathway of carbon flow in aquatic ecosystems that involves the transformation of phytoplankton production into bacterial biomass, which can then be consumed by higher trophic levels.

Phytoplankton: Microscopic, photosynthetic organisms that form the base of the marine food web and serve as primary producers in aquatic environments.