Bacteria living in dense, aggregated communities experience gradients of nutrients, oxygen, and metabolic waste products. Changes in ambient conditions can be considered stresses for constituent cells, and chemical gradients exert heterogeneous stresses within dense bacterial communities, such as biofilms. In order to survive and thrive, bacteria have adapted genetically regulated responses to limitations or excess of these chemicals. Stress responses relevant to biofilms include limitations of oxygen, carbon and nitrogen sources for cells on the interior of biofilms due to their consumption by cells on the periphery, and osmotic and acid stress due to secretion of biomolecules and metabolites. These and other stress response mechanisms have profound effects on metabolism, and as a result, induce heterogeneity of metabolic states of constituent cells. A better understanding of the dynamics and biogeography of metabolic variation within biofilms is important to the fields of biomedical infections and microbial biotechnology. Biotechnologies based on bacterial consortia benefit from controlling and amplifying metabolic processes. Bacterial biofilm infections are recalcitrant and generally more resistant to antimicrobial therapies due to the presence of metabolically dormant subpopulations of cells. Emerging methods of mapping, in space and time, the dynamics and distribution of metabolic states of cells within bacterial communities promise to provide new insights into their function and new strategies to control them. This chapter will review the stresses and stress responses within bacterial communities, and survey the new technologies being used to map their metabolic consequences.