Research Interests
My current research interests focus on three main areas: 1) the role of marine viruses on microbial mortality and diversification; 2) population dynamics of virio- and bacterio-plankton in the Chesapeake Bay over time and space; 3) microbial genomics and community proteomics: a goal to understand microbial function and microgeochemical processes in nature.

Bacteria and bacteriophage are the two most abundant biological components in the sea. Viral lysis of bacteria and production of phage particles occurs continuously in seawater. Marine viruses are known to play a key role on regulating microbial biomass and production. However, little is known about the role of marine viruses on microbial population structure, genetic diversification, and genomic evolution. Our lab uses cyanobacteria and cyanophage as a model system to study the complex interaction between bacteria and their phages. Specific gene markers, including photosynthetic genes psbA and RuBisCO, ITS, viral capsid gene (g20), and DNA polymerase gene, have been developed in our lab to co-monitor the populations of both cyanobacteria (Synechococcus) and cyanophage in the Chesapeake Bay. With more than three-year data from the Bay, we are able to address the questions like: How diverse are cyanobacteria and cyanophage in the Bay? How does the phage-host system change temporally and spatially?

To highlight some exciting research achievements, the first cyanophage genome was sequenced and characterized in our lab. We first applied the SYBR Gold nucleic acid stain to enumerate viruses and bacteria in seawater [SYBR Gold protocol]. We have successfully applied community-based proteomics (2-D gel and LC-MS/MS) to characterize estuarine microbial communities, and link the protein characterization to the Sargasso Sea metagenomic database. A unique group of picocyanobacteria (Marine Cluster B Synechococcus) and their phages were found and isolated from the Chesapeake estuary. Based on our 3-yr survey in the Bay, we found that the majority of bacterioplankton exhibited repeatable seasonal patterns. Moreover, Chesapeake Bay bacterioplankton exhibited stronger seasonal than spatial variations.