Based on the biomass spectrum theory, we aimed to estimate patterns in the carbon cycling efficiency of zooplankton communities with the samples from northwest Svalbard in spring 2015 (May-June). Samples were size fractionated at different depth layers and stations to discover biomass spectra and trophic levels within a community. Zooplankton biomass density was higher in the shallower than the deeper water in all stations even though there was no systematic change of size composition with depth. From integrated biomass densities in the top two layers at each station, Station 28 in the Nansen Basin and Station 19 on the shelf exhibited the highest abundancy while the stations on the slope had intermediate values. The number of trophic levels through which carbon was transmitted in the zooplankton community were calculated by measured biomass spectra and assuming a single mean assimilation efficiency. Afterwards, food web structure analysis was performed with measured biomass spectrum and computed trophic levels based on nitrogen stable isotope measurements. Computed trophic levels from stable isotope measurements and the measured slopes of biomass spectra brought partly different results compare to previous studies. A station on the shelf region with shallower depth had the steepest slope and the highest trophic levels at the same time. The computed assimilation efficiency was the lowest in the shelf region. Our results imply that assimilation efficiency has to be investigated with samples from the areas with different environmental properties. Identifying assimilation efficiency in the changeable polar region, especially, will provide information about the impacts of Climate Change on a food web structure in the ecosystem.