Thursday, January 11, 2018 at 11:00am to 12:00pm
Hancock Foundation Building (AHF), 153/Torrey Webb Room
3616 Trousdale Parkway, Los Angeles, CA 90089
Dr. Cynthia Silveira, San Diego State Univ.
From phage to sharks: The role of viruses in coral reef organic carbon fluxes
Overfishing is among the most pressing threats to coral reefs worldwide, causing the depletion of fish biomass and changes in benthic community structure. Large fish act as long-lived carbon sinks, and their removal causes significant shifts in ecosystem organic matter and energy fluxes that are mediated by heterotrophic microbes. During reef degradation, fleshy algae dominate the reef surfaces and stimulate the growth of super-heterotrophic bacteria, which consume large amounts of organic carbon. Metabolic shifts displayed by these bacteria enable their escape from viral predation by favoring lysogenic infections, when viruses integrate in the bacterial genome. During lysogeny, the integrated phage does not lyse the bacterial host, therefore reducing viral top-down control on the bacterial community. Lysogenic viruses also increase the transfer of genes involved in bacteria-eukaryote interactions that can enhance bacterial fitness and lead to the rise of bacterial pathogens. Together, changes in microbial metabolism and phage replication strategies upon overfishing promote an increase in microbial biomass, significantly modifying trophic relationships, and further disrupting coral reef health.