Award: OCE-1155426

Paleoecological, archeological and historical data provides the only means for extending ecological records far enough back in time to document long-term variability of marine ecosystems, such as driven by environmental change and human activities, over evolutionarily- and ecologically-relevant timescales. Ecological data are typically measured over short time frames and do not encompass natural cycles of environmental variation. As a result, such data are often inadequate to determine the ecological impacts of human activities. Sea otters were highly impacted by humans through the hunting for their furs in the 18th and 19th centuries. They were subsequent reintroduced as they neared extinction. This project is evaluating the trophic position of sea otters over thousands of years prior to and including this period. We have quantified the trophic position of this top predator over thousands of years in and around Kodiak Island and comparing that to the trophic positions of sea otters in the Sanak archipelago over the same time periods. We used the stable isotopes of carbon and nitrogen to compare past and present sea otter food webs and ecosystems. Samples were obtained from archeological sites, historical specimens, and recent samples. This type of project, utilizing paleoecological, paleoclimate and archaeological data is a new approach, and therefore pushed the development of interdisciplinary, truly long-term research. For this project, we sampled, cataloged and measured more than 3500 specimens of 40 intertidal species from 6 sites around Kodiak Island. Of these samples, 670 were prepared and analyzed for carbon and nitrogen stable isotope analysis. In general, stable isotopic variations between organisms reflect different feeding strategies and habitats, and relate to the isotopic composition at the base of a food web. For example, primary producers (plants) in marine environments, such as phytoplankton, algae and sea grasses, all fractionate carbon differently during photosynthesis so the carbon isotope ratio (δ13C) is often a measure of which plants are found at the base of the food chain. There is a difference in the δ13C of organisms that feed on phytoplankton vs. those that feed on kelp. In a marine food web δ13C increases about 2‰ from primary producers to grazers and then 0.5 -1‰ per trophic level (or step up the food chain). Changes in nitrogen isotope ratios (δ15N) are larger, increasing about 3‰ per trophic level. Therefore, it is very helpful in placing an organism into its proper place in the food web. In the course of this project, several undergraduate and graduate students in the STEM disciplines were trained in laboratory procedures, including the preparation of samples for isotope analysis. Through participation in "Dig Afognak", a culture camp run by the Native Village of Afognak, in 2012 and 2013, senior research personnel gained the opportunity to interact with grade-school age children, promoting science in general. More specifically, we informed this group on scientific collection methods and teaching about Kodiak?s intertidal ecosystem. This was in conjunction with the Adventure EARTH week of Dig Afognak. We discussed this project, intertidal ecology, and the use of stable isotopes with elders and others from the community who had volunteered to chaperone and teach the campers. We also spoke at Kodiak Island, Alaska's Alutiiq Museum?s evening lecture series in October 2012, discussing the project and accomplishments. The Alutiiq Museum published a short article about the project in May 2013, aimed for a general audiences, in its newsletter authored by project personnel. We also participated in a stable isotope demonstration for high school and grade school science teachers in rural Alaska in order for them to learn about stable isotope techniques, and how such information is relevant to students in rural Alaska. The sea otter project was highlighted, using past and present sea otter food web data to demonstrate the use of stable isotope in ecology and paleoecology. Data from this project was presented at three professional meetings and at the Sitka WhaleFest in 2015. Last Modified: 01/24/2018 Submitted by: Bruce P Finney