The use of salt as road de-icing agents increases sodium and chloride concentrations in urban streams. Increasing chloride levels are harmful to aquatic organisms and can alter nutrient cycling in ecosystems. Unionid mussels maintain the lowest internal salt concentration of any freshwater organism, making them particularly sensitive to increases in stream water salinity, resulting in physiological stress. Mussels play a critical role in nutrient cycling by filtering particulate nitrogen from the water column and transferring it to sediments through excretion and biodeposition, thereby enhancing sediment carbon, nitrogen, and phosphorus availability and promoting denitrification. There is growing concern for how elevated NaCl affects mussel condition and their influence on ecosystem processes. To evaluate the effects of sub-lethal NaCl concentrations on mussel nutrient dynamics and energy storage, we conducted a 28-day laboratory study on Elliptio complanata. Mussels were exposed to NaCl treatments of varying concentrations based on urban stream monitoring data. We then quantified filtration, excretion, biodeposition, and condition index. We predicted that increased salinity would result in decreased condition due to depletion of stored energy, likely caused by reduced filtration rates and avoidance behaviors (i.e., clamming-up). We predicted that these changes would, in turn, decrease ammonium excretion and biodeposition, with cascading effects on nutrient cycling. We found preliminarily that as NaCl increased, mussel biodeposits initially decreased at day 7 of the experiment, before eventually increasing at day 28, contrary to our prediction. Quantifying how condition index, filtration, excretion, and biodeposition respond to elevated NaCl levels can improve understanding of mussel resilience and support mussel restoration efforts. If mussels can promote the removal of excess nitrogen in streams that are being salinized, findings could inform the implementation of mussel-mediated denitrification as a mitigation tool for excess nitrogen in urban streams.