Benthic faunal assimilation pathways and depth-related changes in food-web structure across the Canadian Arctic

Influence of terrestrial organic matter in marine food webs of the Beaufort Sea shelf and slope

“…Søreide et al 2006, Iken et al 2010. However, recent studies indicate that a depth-stratified approach to defining a baseline is critical when comparing benthic food webs over considerable water depths (Bergmann et al 2009, Roy et al 2015. Given the steep bathymetry of the Beaufort slope and the complex hydrodynamic processes of the region (Pickart 2004, Macdonald & Yu 2006, Hwang et al 2008, near-surface pPOM does not sink entirely vertically and unprocessed through the water column (Forest et al 2013) to underlying benthic consumers.…”

“…Sea ice algae can be an important food source in Arctic systems (McMahon et al 2006, Roy et al 2015; however, this study sampled during the ice-free summer period. To include a sea ice algal end member reference value in the trophic mixing models, ice POM (iPOM) was collected off the northwest coast of Barrow, AK at 71.3815°N, 156.5243°W on 8 April 2014.…”

“…Food web length was determined by assuming an average 3.4 ‰ increase in δ Roy et al 2015). The design of our study did not allow for reliable calculation of a scaled trophic enrichment factor framework, which may more accurately represent smaller isotopic fractionation steps with increasing trophic levels (Hussey et al 2014).…”

“…N enrichment with depth demonstrates the importance of using a depth-normalized approach to food web analysis (Roy et al 2015) to correct for variables related to station bottom depth, and their effect on stable isotope values. In this study, the use of the δ 15 N value of the benthic primary consumer O. sericeum as a food web baseline normalized shelf and slope food web lengths, correcting for any systematic depth-related variable effects on food web length.…”

Ice algae versus phytoplankton: resource utilization by Arctic deep sea macroinfauna revealed through isotope labelling experiments

“…These studies have shown that while the benthos in some areas seem to largely utilize ice algal food (Hobson et al 2002, Brown & Belt 2012, Søreide et al 2013, Roy et al 2015, the contributions of ice algae to consumer diets in other areas seem negligible (Hobson et al 1995, Lovvorn et al 2005, McTigue & Dunton 2014, North et al 2014. However, despite their usefulness in assessing longterm accumulation of different C sources into the consumer tissues, methodological restrictions associated with the analyses can make result interpretation difficult (Coffin et al 1990, Brown & Belt 2012, or introduce a seasonal sampling bias underestimating ice algal contributions to consumer diets (Kaufman et al 2008).…”