During summer 2020, Drew Harvell, professor of ecology and evolutionary biology, postdoc Lillian Aoki and Ph.D. student Olivia Graham traveled to the San Juan Islands off the coast of Washington state to study the pathogenic causes of seagrass wasting disease.
You can follow along on their marine adventures on Twitter: @DrewHarvell, @lillian_aoki, @o_jgraham
Similar to how COVID-19 has swept through society, marine disease agents — like viruses, bacteria and protists — can have massive impacts that ripple through ecosystems. The triggers for epidemics in nature are just as complex, involving a combination of variables such as host stress, environmental conditions and changes in biological communities.
At Cornell CALS, the Harvell Lab is working on a collaborative project with six other universities and the Smithsonian Institution, to study a disease outbreak in West Coast eelgrass.
Eelgrass is a flowering underwater plant with blades that can reach lengths of three meters and create vibrant meadows that are ecologically, economically and culturally valuable. They provide key habitat for baby fish and invertebrates, and they can also sequester carbon, stabilize shorelines and filter pathogens.
However, seagrass wasting disease threatens eelgrass and the key ecosystem services it provides. The disease is highly infectious, creating necrotic lesions that impede photosynthesis and lead to devastating die-offs. Our goal is to discover how changing climate and biological diversity affect seagrass wasting disease. Specifically, we want to find out if some eelgrass residents — invertebrate herbivores — can spread the disease.
Our approach
This past summer, our field team conducted surveys and drone-mapping along the Pacific coast in Oregon and Washington. By mapping eelgrass meadows from year to year, we can see if they are growing or declining. This, in conjunction with field surveys, allows us to better understand the impact of climate change on eelgrass health. Our photos below show the July field surveys led by Lillian Aoki and the August drone-mapping led by Olivia Graham, Bo Yang, postdoctoral research scholar at the University of Central Florida, and Tom and Ryan Palmateer, drone pilot volunteers.
Back in Ithaca, we have been collaborating with Carla Gomes, the Ronald C. and Antonia V. Nielsen Professor of Computing and Information Science and the director of the Institute for Computational Sustainability, and Ph.D. student Brendan Rappazzo, M. Eng. ’18.
By hand, it can easily take 30 minutes to measure disease on one eelgrass blade. However, Carla and Brendan have developed a computer learning algorithm that uses complex computational artificial intelligence to measure disease levels on eelgrass by sorting through thousands of eelgrass blade images in a few minutes to precisely quantify lesions. By leveraging this tool, our team can measure disease more quickly and accurately than ever before.
