Marine biology research

Research at Rosario seeks to uncover causes of seagrass loss in the Salish Sea

Two students measuring underwater grasses
Factors that may contribute to seagrass wasting disease include pathogen load on the plant, warming seawater due to climate change, and nutrient run-off from the land.

For 10 weeks this last summer, Cecilia Brothers, Walla Walla University assistant professor of biology, and four undergraduate biology students, waded the waters of the Salish Sea to research the causes of seagrass wasting disease in the seagrass beds around Rosario. 

Seagrass wasting disease is caused by a tiny marine eukaryotic organism that produces dark lesions on the seagrass blades. This reduces how much the seagrass can photosynthesize, eventually killing the plant. Recent studies have indicated that 50% of the seagrass meadows in the Salish Sea, where the WWU Rosario Beach Marine Laboratory is located, are affected by outbreaks of seagrass wasting disease.

Brothers was awarded $58,926 by the M.J. Murdock Charitable Trust Grant to help with her research. She is specifically interested in researching “what factors influence outbreaks of seagrass wasting disease in the Salish Sea and to what extent can we predict, and therefore prevent, disease outbreaks.”

Brothers and the four students involved with the project located seagrass beds around the Salish Sea and began their research. They found that disease severity and percentage of diseased seagrass plants varied among each of the nine fields they studied. Factors that may contribute to seagrass wasting disease include pathogen load on the plant, warming seawater due to climate change, and nutrient run-off from the land. Seagrass beds are important since in growing near the shores, they reduce coastal erosion, filter sewage and pathogens from the water, and provide nurseries and habitats for marine animals. 

While the group plans to eventually study other factors, they first decided to isolate and research the effects of nutrient run-off on seagrasses. They found connections between vulnerability to disease and the levels of nitrates and phosphates in the surrounding seawater. They successfully got seagrass to grow in a lab, and throughout the rest of the year in labs at WWU they will continue to study the factors that contribute to seagrass wasting disease. 

“It is a fun opportunity for students and a learning experience for them,” remarks Brothers. “It was my first summer at Rosario as a faculty and being part of this project exceeded my expectations in every way. Rosario is a great place!”

Posted Nov. 4, 2019

Four college students wading through a bay
Biology students wade in a bay near Rosario Beach Marine Laboratory as part of their research to study the health of seagrass fields.

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