Small-scale variability in benthic food webs in the Northeastern Chukchi Sea

Abstract

Benthic food web structure can differ over large scales across Arctic shelves in relation to hydrographic conditions, but little is known if such differences also may occur on smaller scales in hydrographically complex areas. The length, food sources, trophic composition, and energy distribution of benthic food webs in three study areas in the northeastern Chukchi Sea (i.e., Klondike, Burger, and Statoil, as part of the Chukchi Sea Environmental Studies Program) were compared using stable isotope analysis and bomb calorimetry. Food web length (four trophic levels), food sources, and linear models of food webs were comparable among areas. Marked differences in food web structure were observed when trophic levels were quantified by benthic biomass and abundance. High proportions of biomass and abundance of trophic level 3 taxa at Burger were attributed to high deposition of refractory material. High proportions of trophic level 1 and 2 taxa at Klondike and Statoil reflected availability of fresh material. Burger could potentially present a rich foraging ground for some benthic predators due to especially high benthic prey energy densities. Findings emphasize that marine food webs can vary on small spatial scales in accordance with hydrographic conditions, particularly when quantitative trophic level distribution is considered.