Body size is one of the most significant functional traits of an organism, while the size spectrum defines the functioning of a multispecies community. Body size affects energetics, which is why changes in body size have implications for resilience to climate change at both individual and community scales. To investigate the influence of changing environmental conditions on body size, secondary production, and carbon demand of deep-sea benthos in the Fram Strait, the passage between NE Greenland and the Svalbard archipelago, we analyzed meiofauna and macrofauna samples collected in 2000, 2010, and 2017 at station depths ranging from 973 m to 5561 m. Surface sediments were collected using a box corer to assess the influence of environmental changes on the structure (biomass size spectra) and functioning (secondary production and carbon demand) of benthic communities. At depths between 900 and 1500 m (RIDGE), macrofauna individual biomass decreased from 2000 to 2017. However, at depths below 2000 m, it remained at a similar level across the studied years. In all bathymetric zones, macrofauna secondary production and carbon demand remained stable across the three years. In contrast, nematodes individual biomass, total biomass and secondary production decreased from 2000 to 2017. Results of DISTLM model confirmed that nematodes did not rely on the bacterial activity (indicated by FDA). Responses of benthic biomass size spectra to the environmental changes varied among bathymetric zones. The decreasing nematodes standing stocks and magnitude of its functioning may be due to an increasing interference competition with macrofauna.