Perspectives on the wasting disease of eelgrass Zostera marina

Abstract

Early in the 1930's a major epidemic decimated populations of eelgrass Zostera manna L. along the Atlantic coast of North America and Europe. Over 90 % of the eelgrass populations disappeared, resulting in dramatic changes within the coastal ecosystem. There was much speculation about the possible causes of the wasting disease ranging from pathogen~c microorganisms to abiotic factors including changes in temperature, precipitation, salinity, and pollution In a critical review of the Literature, substantial research supported the view that a specles of the genus Labyrinthula, a marine slime mold, was the primary causative agent of the epidemic dlsease This hypothesis was consistently supported by data collected throughout the range of diseased eelgrass populations. In the present recurrence of eelgrass wasting disease, a pathogenic species, Labyrinthula zosterae has been identified as the causative agent of the disease. Similarities of past and present wasting disease episodes further support the hypothesis that Labyrinthula is the primary etiological agent.

What was natural in the coastal oceans?

“…Decline of the eelgrass Zostera marina was due primarily to wasting disease caused by the slime mold Labyrinthula sp., the same genus of pathogen affecting turtlegrass in Florida Bay (14,82). Earliest reports of declines in eelgrass date from the 1890s, but mortality affecting Ͼ90% of eelgrass populations along the entire East Coast of North America occurred in the 1930s (14,82).…”

Marine Phytophthora species can hamper conservation and restoration of vegetated coastal ecosystems

“…Massive disease-driven die-offs of seagrasses [18,19] and mangroves [20,21] illustrate the potential harm to a population as a consequence of an outbreak. For instance, the pathogen Labyrinthula zosterae was the purported pathogen responsible for the loss of up to 90% of the Z. marina beds across the North Atlantic region in the 1930s [19,22], which eventually resulted in the loss of ecological properties such as the rich faunal or waterfowl communities often associated with Z. marina [23,24]. Thus, the ecological ramifications of such large die-offs are not limited to the infected species alone.…”

Impact of the wasting disease pathogen, Labyrinthula zosterae, on the photobiology of eelgrass Zostera marina

“…During the 1930's, 'wasting disease' decimated the eelgrass Zostera marina L. meadows along the Atlantic Coast of North America and Europe with over 90% loss (Muehlstein 1989). Speculations concerning the causative agents of the wasting disease have been numerous, including pathogenic microorganisms, salinity, temperature, irradiance, drought and oil pollution , Muehlstein 1989).…”

“…Speculations concerning the causative agents of the wasting disease have been numerous, including pathogenic microorganisms, salinity, temperature, irradiance, drought and oil pollution , Muehlstein 1989). It has now been shown that the eelgrass wasting disease is caused by infection with a marine slime mould-like protist, Labyrinthula zosterae Porter & Muehlstein (phylum Labyrinthulomycota) (Short et al 1987, Muehlstein et al 1991.…”