This project has further developed the use of stable isotopes to tie past and present ecosystems together. Scholars have argued that conventional ecological data are inadequate to measure the ecological impacts of human activities because most observations are too recent to encompass natural cycles of environmental variation. In looking beyond the past few decades, this project is evaluating the trophic position of sea otters, a species highly impacted by human fur exploitation and subsequent reintroduction, into the deeper past. Using paleoecological, archeological and historical data provides the only means for extending ecological records far enough back in time to document the characteristic variability of marine ecosystems, the impact ifand environmental change over evolutionarily- and ecologically-relevant timescales. We are quantifying the trophic position of sea otters, a 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. This type of project, utilizing paleoecological, paleoclimate and archaeological data is still new and therefore pushed the development of interdisciplinary, truly long-term research.

We have sampled, cataloged and measured upwards of 3500 specimens of 40 intertidal species from 6 sites around Kodiak Island. 670 of those 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. The same principle holds for terrestrial ecosystems. There will be a difference in the δ¹³C of organisms that feed on phytoplankton and 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 for every step up the food chain. It increases about 3‰ per trophic level so it is most helpful in placing an organism into its proper place in the food web.

This project was the first funded for a female early career scholar as a PI. The project was crucial in the PI’s development; including the first opportunity for her to be the primary person to organize two lengthy field season in remote locations. The PI and her collaborators were able to develop contacts and promote science within the Native community of Kodiak and among the broader Kodiak community. In the course of this project, four female undergraduates and one female graduate student in the STEM disciplines were trained in laboratory procedures in general and specifically in preparation of samples for isotope analysis. This was a first-time opportunity for the undergraduates to work regularly in a laboratory setting. This training also aided the graduate student in completing isotope analyses for her thesis that she would not have otherwise had the training to complete.

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 and specifically scientific collection methods and teaching about Kodiak’s intertidal ecosystem. This was in conjunction with the Adventure EARTH week of Dig Afognak. While there they often discussed their 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. The PI spoke at the Alutiiq Museum’s evening lecture series in October 2012, discussing the project and accomplishments during the summer field season. The Alutiiq Museum also published a short article about the project in May 2013, aimed for a general audiences, in its newsletter authored by project personnel. The project PI 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 what types of information can be derived from isotope data that 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. The outreach event was jointly organized by the University of Alaska Corporative Extension Service (CES), the Center for Ocean Science Education Excellence (COSEE) and the Alaska Stable Isotope Facility. Data from this project was presented at three professional meetings and at the Sitka WhaleFest in 2015.

Last Modified: 09/30/2016
Modified by: Nicole Misarti