Sometimes – maybe even often? – the most interesting results we get in our scientific endeavors are the unexpected ones, not the ones that confirm our hypotheses.  These “what, really?” results can lead into exciting new directions and spawn new discoveries.  Here Becca Maher describes one such result found with collaborators in the community of microorganisms that live on seagrass blades.  Getting to the bottom of factors that affect the severity of eelgrass wasting disease is critical for predicting disease vulnerability and perhaps finding ways to restore our essential eelgrass beds.

Best,
Dr. Megan Dethier, FHL Director
Make your gift today

Genomics at the Shoreline: Microbes, Meadows and Community at FHL

by Becca Maher, PhD

During my time at Friday Harbor Laboratories as the Marine Genomics Postdoctoral Fellow, I never imagined that my husband would be wearing nitrile gloves and opening sterile tubes for me while I collected microbial samples. Before coming to FHL, my work had taken me either to remote field sites or into university labs, places where my research felt separate from daily life and far removed from the people closest to me. That changed at FHL. We were fully immersed in the ecosystem I was studying, and the boundary between fieldwork and everyday life dissolved in a way that made the science both more immediate and more personal.

As a microbiologist and avid hiker, I spent many weekends walking along the beaches of San Juan Island, thinking about the tiny organisms that are invisible, yet so integral to life on Earth. We are used to thinking of microbiomes as helpful partners. In humans, gut microbes help us digest food. On plants, microbial communities can support nutrient cycling and defend against pathogens. It seemed reasonable to expect that microbes living on eelgrass leaves would play a similar protective role against eelgrass wasting disease, caused by the protist Labyrinthula zosterae that threatens vital eelgrass meadows. But work led by Drs. Olivia J. Graham and Drew Harvell challenged that assumption. In a series of experiments, eelgrass plants with a disrupted microbiome actually developed less severe disease after exposure to the pathogen. This surprising result challenged a core assumption and became the foundation for my research at FHL.

My research in the Harvell Lab focused on understanding when and how the eelgrass microbiome might influence disease progression. Across both field surveys and controlled experiments, we found that temperature plays a major role. Warmer conditions increased disease severity and were associated with shifts in microbial community composition and diversity. Rather than consistently protecting the host plant, the microbiome appeared to change in ways that could facilitate disease under certain environmental conditions. This work was carried forward in large part by my summer intern, Angela Ayala, through the FHL Research Experience for Undergraduates (REU) program. With remarkable initiative, she led a laboratory heat stress experiment that helped connect these patterns across lab and field settings, demonstrating how training at FHL can equip students to contribute meaningfully to ongoing research.

Through collaborative work with FHL researchers including Drs. Lindsay Alma and Colleen Burge, we found that the pathogen itself is more complex than a single harmful strain. By tracking Labyrinthula populations over space and time, we found that multiple strains coexist within eelgrass meadows. Although strain diversity declined from winter to summer, it did not collapse to a single dominant strain as assumed from classic disease outbreaks. Instead, different strains appeared to occupy distinct ecological niches, with some more associated with host tissue and others more common in the surrounding environment. These patterns suggest that disease outcomes depend not only on the presence of the pathogen, but also on strain identity, environmental conditions, and interactions with the broader microbial community. This improved understanding of pathogen diversity can help inform more effective monitoring and management strategies for eelgrass health, ultimately supporting the conservation of this foundational coastal ecosystem.

A major part of making this work possible was the development of the new Marine Genomics Center at FHL, funded by an NSF grant. I worked closely with Dr. Billie Swalla and stockroom manager Peggy Combs to acquire and set up the equipment, transforming an older lab space which had been remodeled by the FHL Maintenance crew into a modern genomics facility. One of the most exciting parts was getting to test our new MinION sequencing device, a portable platform that allows us to generate genomic data in real time. Being able to move from collecting samples in the field to sequencing DNA just steps from the shoreline opens up new possibilities for research and training. The Center now provides students and researchers with hands-on access to cutting-edge molecular tools, a rare and transformative capability for a marine field station.  Much of my time working in it was generously supported by the Calvin Postdoc Term Fellowship at FHL.

None of this work would have been possible without the incredible community at FHL. Fieldwork in eelgrass meadows is never a solo effort. It takes a team of researchers, students, technicians, and friends willing to work around the tides, brave cold water and late nights, and carefully process samples long after the sun has set. I was fortunate to be surrounded by a group of generous, curious, and deeply committed scientists who made both the work and the experience unforgettable. FHL is one of the few places in the world where you can truly live and work in the ecosystem you study, where collaboration happens as easily on the beach at low tide as it does in the lab.

During my time on the island, my family grew as well. We welcomed a baby boy, and I had the pleasure of helping him explore the same eelgrass meadows that shaped my research. Although we have since moved away from the Labs to be closer to family, the connections I built at FHL, both professional and personal, will stay with me for the rest of my life.

References:

Graham O.J., Adamczyk E.M., Schenk S., Dawkins P., Burke S., Chei E., et al.  2024.  Manipulation of the seagrass-associated microbiome reduces disease severity.  Environmental Microbiology: 26(2), e16582.  https://doi.org/10.1111/1462-2920.16582

Maher R.L., Ayala A.C., Crandall G.A., et al.  2026.  Eelgrass microbiome and disease dynamics under field and lab heat stress.  Environmental Microbiome: 21(4).  https://doi.org/10.1186/s40793-025-00826-y

Tide Bites is a monthly email with the latest news and stories about Friday Harbor Labs.  Want more?  Subscribe to Tide Bites or browse the archives.