Multiple stable isotopic analyses ([delta]¹³C, [delta]¹⁵N, [delta]¹⁸O, and [delta]D) of the Boulder Patch, a high arctic kelp community: trophic and temporal perspectives

Abstract

The Boulder Patch, a high Arctic kelp community, is a rarity in the Alaskan Beaufort Sea. Considered a biodiversity oasis, this area provides habitat for many organisms. Trophic relationships, spatial patterns, and isotopic changes over time were examined within the Boulder Patch using stable carbon and nitrogen isotopes. 394 samples, representing over 55 species were analyzed. Isotope values showed considerable variability in the food web base, particularly for the kelp Laminaria solidungula. Isotopic values for most animals fit their known feeding strategies. Little spatial variation was observed in isotope values, however temporal differences were found in L. solidungula isotope values between 2002 and 2004, and between archived samples collected during the 1980's. To better understand patterns in stable oxygen and hydrogen isotopes, values were assessed and applied in an ecological context. Sixty-four samples were analyzed, encompassing 29 species. Results indicated distinct differences between primary producers and animals, offering insights into a possible application of [delta]¹⁸O and [delta]D in ecological studies. By defining trophic structure and elucidating feeding strategies of organisms, this study enhanced the biological knowledge in the Boulder Patch, providing ecological information on a high arctic kelp community.