Phycodnaviridae is a family of large viruses that primarily infect algae, particularly green algae. These viruses are known for their complex structures and can have a significant impact on algal populations in aquatic ecosystems. They play a crucial role in regulating algal blooms and nutrient cycling in marine and freshwater environments. The members of the Phycodnaviridae family are characterized by their double-stranded DNA genomes and can be quite large compared to other viruses. They are of interest in scientific research for their potential applications in biotechnology and understanding viral evolution in relation to their algal hosts.