Mean satellite-derived chlorophyll <i>a</i> (Sat Chl <i>a</i>), net primary production (NPP) per unit area, annual NPP, and open water area (OW) for different regions of the Barents Sea during the study period.

Means ± SD and coefficient of variation (%) in parentheses are given for the yearly means during the study period (1998–2011, n = 14). CSTW = Coastal west; CSTE = Coastal east; ATLW = Atlantic west; ATLE = Atlantic east, ARC = Arctic and BS = Barents Sea study area. For more details of area definitions see Fig. 1. CSTW is always ice-free, i.e. there is no variability in OW.