Regional benthic food web structure on the Alaska Beaufort Sea shelf

Abstract

Trophic structure and resilience of regional benthic food webs were studied on the Alaska Beaufort Sea shelf across 3 geographic regions (east, central, and west) and 2 depth ranges (14 to 90 m [shallow] and 100 to 220 m [deep]). Carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured from water column and sediment particulate organic matter (POM) as markers of primary food sources and from common benthic invertebrate taxa. Isotopic niche space (δ13C. δ15N) occupied by benthic taxa provided measures of community-wide trophic redundancy and separation. δ13C values of the water column and sediment POM were patchy but generally indicative of terrestrial input across the shelf, especially near the mouth of the Colville River (