Meeting Abstract
Seagrasses inhabit only a small fraction of the world ocean; yet, they provide important ecosystem services such as juvenile salmon nurseries and atmospheric carbon sequestration. Globally, seagrass beds are susceptible to Seagrass Wasting Disease (SWD). Eelgrass Wasting Disease (EGWD) is the variant of SWD occurring in eelgrass (Zostera marina). Entire beds of eelgrass can be infected and destroyed. EGWD is caused by the amoebozoan slime mold Labyrinthula zosterae (LZ). The transmission of LZ in field as well as the functional morphology of LZ colonies have not been extensively studied. In our study, field experiments at different sites in 2017 and 2018 showed that sentinel blades deployed inside and outside eelgrass beds both develop new infections, suggesting the likely transmission of LZ through the water column. Infection prevalence, severity, and disease lesion number were not different between inside and outside eelgrass bed treatments after two weeks of incubation in the field and were significantly higher than in infection baseline control plants. Colony morphology was also studied via phase contrast and confocal microscopy. Analysis of collected environmental samples (including water, sediment, associated algae, and epibiont) would provide finer resolution on the location of LZ in situ and is currently being carried out.
