Eelgrass disease study investigates vulnerability to Labyrinthula

kelpcraboneelgrass-NOAAphotolibrary.-562-410Eelgrass (Zostera marina) plays a key role in the health of the Salish Sea ecosystem. It stabilizes sediments, reduces the impact of wave action, provides habitat, and is an important nursery and foraging area for multiple species, some of which are endangered.

SeaDoc’s involvement in eelgrass issues goes back to 2003, when we convened a meeting of eelgrass experts, resource managers, and land-use specialists to analyze the sudden disappearance of 35 acres of eelgrass in San Juan Island’s Westcott Bay.

Eelgrass can be damaged by pollutants, by shading from docks and structures, and by physical damage from improper anchoring or badly placed moorings. It’s also susceptible to disease, particularly from a slime mold-like organism called Labyrinthula zosterae. And it’s no small threat. This disease wiped out 90% of the eelgrass along the Atlantic coasts of North America and Europe in the 1930s.

We know that the organism is found in the Salish Sea, but the mere presence of a pathogen does not always mean disease. So what are the other factors? A recent publication by Maya Groner and numerous colleagues (supported in part by SeaDoc) used field surveys and experimental manipulations to find out how the age of eelgrass leaves impacts disease prevalence.

The upshot: mature beds and shallow eelgrass beds could be especially susceptible to outbreaks of wasting disease.

View the publication here:
http://www.seadocsociety.org/?p=2427

Photo from NOAA Photo Library via Flickr.