<p>Heterotrophic marine bacteria utilize organic carbon for growth and biomass synthesis. Thus, their variability is key to the balance between the production and consumption of organic matter and ultimately particle export in the ocean. Here we investigate a potential link between bacterial traits and ecosystem functions in a rapidly changing polar marine ecosystem based on a bacteria-oriented ecosystem model. Using a data-assimilation scheme we utilize the observations of bacterial groups with different physiological states to constrain the group-specific bacterial ecosystem functions. We also investigate the association of the modelled bacterial and other ecosystem functions with eight recurrent modes representative of different bacterial taxonomic traits. High nucleic acid (HNA) bacteria show relatively high cell-specific bacterial production, respiration, and utilization of the semi-labile dissolved organic carbon pool compared to low nucleic acid (LNA) bacteria. Both taxonomy and physiological states of the bacteria are strong predictors of bacterial carbon demand, net primary production, and particle export. Numerical experiments under perturbed climate conditions show overall increased bacterial activity and a potential shift from LNA- to HNA-dominated bacterial communities in a warming ocean. Microbial diversity via different taxonomic and physiological traits informs our ecosystem model, providing insights into key bacterial and ecosystem functions in a changing environment.</p>