Goethel, Christina LeighSea ice retreat, seawater warming, and now ocean acidification are recognized as physical stressors impacting the productive benthic communities on the shallow continental shelves of the northern Bering and Chukchi Seas, particularly calcifying organisms like bivalves that are prey items for benthivorous predators including walruses, eiders, and bearded seals. Using time-series benthic faunal collections and laboratory experiments, my research: 1) evaluates the abundance and dominant size class of Macoma calcarea in the northern Bering Sea and the southeastern Chukchi Sea during summer months from 1998-2014, and 2) investigates the effects of ocean acidification on growth and oxygen consumption of two size classes of three dominant bivalve species, M. calcarea, Astarte montagui, and Astarte borealis. Results suggest a northward shift in bivalve distribution (p < 0.01) and a recent size reduction at both sites. Experimental results suggest that one dominant size class (2.1-3 cm) will be more susceptible to ocean acidification.enThesisEnvironmental scienceBering SeaBivavleChukchi SeaOcean AcidificationPacific Arctictime-series