Abstract
Eelgrass (Zostera marina) meadows are key habitats for coastal biodiversity and ecosystem functioning. During the last decades there has been a significant decline in eelgrass beds in Sweden and elsewhere, which has been attributed to human activities. Recurrent mass mortality of eelgrass due to wasting disease caused by a protist pathogen (Labyrinthula) has, however, been observed in different parts of the world throughout the 20th century. In a pilot study we have observed that Labyrinthula is still highly prevalent in eelgrass on the Swedish west coast, and that the infection rate of this pathogen can increase almost tenfold when normal water temperature during summer is increased by 2° C. This project will take advantage of recently developed molecular tools in order to i) provide the first mapping of the prevalence of Labyrinthula infections and genetic variation in pathogen susceptibility within and among eelgrass populations in Sweden, ii) determine mechanisms behind pathogen resistance in eelgrass, iii) estimate the effects of global (increased seawater temperature) and local (tissue damages caused by boating activities) human impact on pathogen susceptibility of eelgrass, and iv) provide the first recommendations on how to deal with the risk of epidemic pathogen outbreaks in the management and restoration of eelgrass beds.
Sweden