Algal viruses are viruses that specifically infect algae, which are important photosynthetic organisms found in aquatic environments. These viruses can influence algal populations and play a significant role in marine and freshwater ecosystems by regulating nutrient cycling and food webs. These viruses can have various effects on their algal hosts, including causing cell lysis, which releases organic matter into the water. This process can impact the availability of nutrients for other organisms, such as zooplankton and bacteria, thereby influencing the overall health of the ecosystem.