Identification of demographic and environmental risk factors associated with eelgrass wasting disease in the Salish Sea

Presentation Abstract

As we increase our studies of marine diseases and their population- and community- level impacts, the role of opportunist pathogens in causing disease is often overlooked. These pathogens are often ubiquitous in the environment, but cause disease only under certain conditions such as immunosuppression due to environmental stress. While direct management of pathogens is often unrealistic in the marine environment, management of the environmental stressors leading to increased vulnerability to disease may be possible. Eelgrass wasting disease, caused by the opportunist pathogen, Labyrinthula zosterae, is commonly associated with severe population declines of the temperate seagrass Zostera marina at times resulting in a local extinction event. While this pathogen is omnipresent, disease outbreaks only occur occasionally. Factors that lead to these outbreaks are largely unknown, however some phenolic compounds have been shown to inhibit L. zosterae in vitro. It has been hypothesized that environmental stressors causing decreased phenolic concentrations will cause more disease. Here we present survey data of a current outbreak of eelgrass wasting disease in the San Juan Archipelago and Northern Puget Sound regions of the Salish Sea. We confirm that lesions in the field are due to infection with Labyrinthula using histology and culturing techniques. Then we describe the relationship between climatic factors including water movement and temperature, host factors including demography and phenolic concentrations and disease prevalence across 11 sites. At some of these sites eelgrass standing stock is in decline. We discuss the relevance of our work to seagrass declines in the Salish Sea and regional practices designed to protect Z. marina.

Session Title

Session S-01E: Eelgrass Wasting Disease

Conference Track

Habitat

Conference Name

Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)

Document Type

Event

Start Date

30-4-2014 10:30 AM

End Date

30-4-2014 12:00 PM

Location

Room 613-614

Genre/Form

conference proceedings; presentations (communicative events)

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Subjects – Topical (LCSH)

Zostera marina--Diseases and pests--Salish Sea (B.C. and Wash.); Environmental risk assessment--Salish Sea (B.C. and Wash.)

Geographic Coverage

Salish Sea (B.C. and Wash.)--Environmental conditions

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

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Apr 30th, 10:30 AM Apr 30th, 12:00 PM

Identification of demographic and environmental risk factors associated with eelgrass wasting disease in the Salish Sea

Room 613-614

As we increase our studies of marine diseases and their population- and community- level impacts, the role of opportunist pathogens in causing disease is often overlooked. These pathogens are often ubiquitous in the environment, but cause disease only under certain conditions such as immunosuppression due to environmental stress. While direct management of pathogens is often unrealistic in the marine environment, management of the environmental stressors leading to increased vulnerability to disease may be possible. Eelgrass wasting disease, caused by the opportunist pathogen, Labyrinthula zosterae, is commonly associated with severe population declines of the temperate seagrass Zostera marina at times resulting in a local extinction event. While this pathogen is omnipresent, disease outbreaks only occur occasionally. Factors that lead to these outbreaks are largely unknown, however some phenolic compounds have been shown to inhibit L. zosterae in vitro. It has been hypothesized that environmental stressors causing decreased phenolic concentrations will cause more disease. Here we present survey data of a current outbreak of eelgrass wasting disease in the San Juan Archipelago and Northern Puget Sound regions of the Salish Sea. We confirm that lesions in the field are due to infection with Labyrinthula using histology and culturing techniques. Then we describe the relationship between climatic factors including water movement and temperature, host factors including demography and phenolic concentrations and disease prevalence across 11 sites. At some of these sites eelgrass standing stock is in decline. We discuss the relevance of our work to seagrass declines in the Salish Sea and regional practices designed to protect Z. marina.