CEB Committe on Evolutionary Biology

SPOTLIGHT: Amy Henry

Amy Henry

Amy Henry at her field site on the San Juan Archipelago. 

I am interested in why organisms live where they live and how biotic interactions (and abiotic interactions) can create interesting spatial patterns of organisms in nature. In particular, I study seagrasses and sand dollars. On sandy beaches in Washington state, these species are both dominant space occupiers. Seagrasses form dense beds that anchor and accumulate sediment and tasty organic matter, increase the oxygen in the water and sediment, and shelter high biodiversity, including juvenile herring and halibut, snails and sea slugs, crabs, worms, and much more. Sand dollars, which are relatives of sea urchins, aggregate and also form dense beds, bumping into each other and churning through sand in the process. Their hustle and bustle prevents many other species from living in these areas, and their aggregative behavior makes for patchiness within sand dollar territory too. When you get both species present on the same beach, like where I study them in the San Juan Archipelago, you get a dynamic, patchy mosaic, like a checkerboard of grass patches and sand dollar patches with slowly shifting boundaries, as they invade and disrupt each other, competing for space.

My research connects the inch-scale processes of what happens when a sand dollar contacts a seagrass shoot to the football-field-scale changing landscape of the beach. First, using field experiments I'm measuring how conditions change within the different kinds of beds as a result of these engineering activities and how these alterations affect rates of growth and territory change for each species. Second, using the data I’ve collected in my field experiments, I’m using the rates of growth and change to build probabilistic models that predict the future distributions of species on the beach, testing different hypotheses about what factors are important to patterns. I’m using a time-series of aerial images of my field site to test these predictions against what’s actually happening on longer scales of time and space. Finally, I’m integrating lab experiments examining sand dollar aggregative behavior with individual-based models to test whether this neat behavior affects landscape-level processes.

That’s the big picture. On a day-to-day, however, I spend a lot of time with my face uncomfortably close to lots of wet sand, counting blades of grass. My field experiments are on a public beach, so many people stop while walking their dog to ask what I’m doing. While I can’t spend too much of my limited low-tide-time chatting, I always take a few minutes to explain. In the process, I’ve become something of an accessible science personality in this small community, and regularly answer (and do background research to prepare for) questions about red tides, clamming regulations, marine diseases, nuclear radiation from Japan, and climate change. These conversations have given me great insights into what issues people care about and are curious about, and I’ve honed my elevator speech to suit everyone from school kids to local business owners to vacationers from all walks of life.

My favorite part is getting to really, really know my study system. I’ve visited my field site over 80 times now over three summers, and I’ve learned so much beyond my research project: the increase in bubble snails in the high zone seems to be an annual breeding migration, the neon green color of the water sometimes is seagrass pollen, and translucent baby halibut are incredibly well-camoflaged. I can tell when the tide has turned from subtle changes in the smell of the air, the sound of the waves, a change in the breeze. I love the watermelon-scented jelly-like sea slugs (Melibe leonina) that float by on the incoming tide, and the otters that pop in to try to figure out what this weird wader-clad human is doing. The little observations remind me that there are tons of interactions happening, and there will always be more to study and learn. See you on the beach!

Connect with Amy Henry.
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