Modern samples of N. pachyderma (s.) from the Northeast Water Polynya provide a means for studying how environmental conditions affect the vertical distribution and chemistry of this species. Highest abundances of N. pachyderma (s.) were associated with the chlorophyll maximum in the surface 20-80 m. Evidence suggests that the addition of a calcite crust modifies the calcite tests of some N. pachyderma (s.) between 50 and 200 m. The oxygen isotope composition of N. pachyderma (s.) shells increase by 1.5‰ in response to local water column gradients. The δ 1 3 C values of N. pachyderma (s.) are basically invariant with depth in this region, are consistently 1.0‰ depleted in comparison with the δ 1 3 C for equilibrium calcite.