4500 years of Sea Otters: WERC faculty member prepares for second field season researching intertidal food webs

May 16, 2013 • Filed under: News — melanie.rohr

Here’s a concept: Food webs–those simple drawings of algae, fish, eagles, and bears that most of us first encounter in elementary school–describe a key component of ecosystem dynamics. The interactions of individuals in food webs define ecosystems, and when changes occur to one species, there are broader implications for the entire web.

WERC’s assistant research professor Dr. Nicole Misarti is researching this concept by studying one keystone predator species, the sea otter, and how it impacts sub-arctic island food webs.

Hand drawn sketch illustrating a portion of the near-shore ecosystem foodchain.

A simplified food chain that is a portion of the larger near-shore ecosystem.

Misarti’s work is a joint project with biologist Bruce Finney (Idaho State University), ecologist Spencer Wood (Stanford University) and zooarchaeologist Michael Etnier (Western Washington University). The researchers are using stable isotope analysis on samples of bone collagen, shell, and intertidal organisms from Sanak and Kodiak Islands in the northeast Pacific Ocean to evaluate the trophic structure of sea otter populations over the past 4500 years.

Misarti and her colleagues are concerned with ecosystem productivity, diversity, and resilience to future change. Previous research shows sea otters as keystone predators whose presence or absence appears to determine the overall diversity and productivity of kelp forests which in turn affect populations of fish, seals, and potentially even bald eagles.

Intertidal creatures

Denizens of the intertidal; Larsen Bay, Kodiak Island.

Through analyzing the diet of sea otters and the trophic structure of rocky intertidal shores over thousands of years, the research team will also be able to see how ecosystem change is correlated with changes in climate and/or human activity. “One of the questions is why the modern data for Kodiak sea otters looked so different from the modern Sanak Island otters,” said Misarti. “Sanak’s population numbers have been up and down since the first interaction with humans but are now declining; Kodiak’s populations have been increasing in the last decades.”
Misarti’s work as a research scientist has its own seasonal cycle: logistics, fieldwork, analysis, dissemination. As she prepares for the upcoming field season, she reflects on the successes of last summer, “The first season went really well. We got everything done. Right now, I have people in the lab processing samples and the lab work is chugging along. But we are ready to go out [into the field] again.”

Researcher standing at pebbly beach in the morning sun

The start of a beautiful day in the field near Crag Point.

This summer Misarti and her team will return to the islands and collect data from the same bays and shores. A large component of this project is outreach. “Last year we worked with the Dig Afognak culture camp for kids,” Misarti explained. “We had great discussions and, at low tide, had the campers help with sample collection and we talked about food webs and sea otters. We also had quite a few teachers and elders teach and engage, which wound up being a good forum to pass along traditional knowledge about the nearshore ecosystem. We weren’t sure how it would work with the kids but it went well and we are invited back.”

Even with the ups and downs of unpredictable weather, equipment malfunctions, and other mishaps that are part of the field experience, Misarti is looking forward to this year’s field work. She states that there are many benefits to this study including gauging the overall health of the nearshore ecosystem, relevance due to high interest from local communities, some who use the intertidal resources, and for tourists who are drawn to the sea otters.

Learn more about Nicole Misarti and her research projects at
http://ine.uaf.edu/werc/people/nicole-misarti/

View towards ocean under blue skies overlooking a healthy bed of kelp.

A healthy kelp bed near Chiniak.

All images provided by Nicole Misarti.