**Not yet funded – but we are interested in pursuing this work**

Seagrasses are enormously important constituents of coastal marine habitats, and are threatened by climate change, eutrophication, and disease. Microbial biogeochemistry in seawater and sediments may influence, both directly and indirectly, the outcome of virus-host interactions in marine habitats. Seagrasses persist in sediments with very large amounts of toxic sulfide, which is made possible by the activities of sulfide oxidizing bacteria. At the same time, sulfide plays an important role in viral replication by moderating inflammatory responses to viral infection. Thus, sulfide oxidizers in seagrass sediments may enable stable co-existence between seagrasses and their viruses. We hope to study the interactions between sulfide, oxygen conditions, and viral replication within seagrass tissues, and assess whether disruption to sulfide pools by eutrophication may result in altered host-virus dynamics that are reflected in host transcriptomic and population genetic markers.