MEPS 594:1-19 (2018) - DOI: https://doi.org/10.3354/meps12582
FEATURE ARTICLE
Benthic-pelagic trophic coupling in an Arctic marine food web along vertical water mass and organic matter gradients
Ashley D. Stasko1,2,*, Bodil A. Bluhm3, Christine Michel2, Philippe Archambault4, Andrew Majewski2, James D. Reist2, Heidi Swanson1, Michael Power1
ABSTRACT: Understanding drivers of benthic-pelagic coupling in Arctic marine ecosystems is key to identifying benthic areas that may be sensitive to climate-driven changes in hydrography and surface production. We coupled algal biomass and sedimentary characteristics with stable isotope data for 113 fishes and invertebrates in the Canadian Beaufort Sea and Amundsen Gulf to examine how trophic structure was influenced by the vertical water mass structure and by organic matter input regimes, from 20 to 1000 m depths. Indices of community-level trophic diversity (isotopic niche size, 13C enrichment relative to a pelagic baseline, and δ13C isotopic range) increased from west to east, coincident with the use of more diverse dietary carbon sources among benthic functional groups. Data suggested benthic-pelagic trophic coupling was strongest in the western study region where pelagic sinking flux is relatively high, intermediate in the central region dominated by riverine inputs of terrestrial organic matter, and weakest in the east where strong pelagic grazing is known to limit sinking flux. Differences in δ13C between pelagic and benthic functional groups (up to 5.7‰) increased from west to east, and from the nearshore shelf to the upper slope. On the upper slope, much of the sinking organic matter may be intercepted in the water column, and dynamic hydrography likely diversifies available food sources. In waters >750 m there were no clear trends in benthic-pelagic coupling or community-level trophic diversity. This study represents the first description of fish and invertebrate food web structure >200 m in the Canadian Beaufort Sea.
KEY WORDS: Water column · Benthic food supply · Beaufort Sea · Niche dimensions
Full text in pdf format  Information about this Feature Article  Supplementary material Supplementary material | Cite this article as: Stasko AD, Bluhm BA, Michel C, Archambault P and others (2018) Benthic-pelagic trophic coupling in an Arctic marine food web along vertical water mass and organic matter gradients. Mar Ecol Prog Ser 594:1-19. https://doi.org/10.3354/meps12582
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