Weak seasonality in benthic food web structure within an Arctic inflow shelf region

•Isotopic niche areas of functional groups changed minimally between seasons.•Change in food quality at the seafloor lagged the spring bloom by up to six months.•Only two species showed 13C-enrichment consistent with sea-ice algal assimilation.•Deposit feeders had the most seasonally consistent isotopic niche.•Diet plasticity in several taxa apparent from isotopic niche areas.