Microfluidics has revolutionized the study of microbial ecology by enabling the observation and quantification of microbial processes at the single-cell level, providing a high degree of control over environmental conditions. This review highlights recent advancements in microfluidic systems that have enriched our understanding of microbial life and communities. Key applications include: 1. **Single-Cell Responses to Environmental Fluctuations**: Microfluidic devices, such as the 'Mother Machine,' allow for precise control over environmental shifts, enabling the study of bacterial responses to temporal fluctuations. These studies reveal phenotypic heterogeneity among individual cells and how it affects population-level responses. 2. **Navigation in Spatially Heterogeneous Environments**: Microfluidics is used to study microbial chemotaxis in complex environments, including oceanic and soil habitats. Devices with source-sink designs generate chemical gradients, allowing researchers to track bacterial movement and interactions with environmental cues. Studies have shown that bacteria adapt to spatial gradients through chemotaxis, thermotaxis, and aerotaxis, influencing their survival and ecological roles. 3. **Two-Dimensional Microcolonies and Collective Behaviors**: Microfluidic platforms, such as the Family Machine, enable the long-term observation of metabolic heterogeneity and collective behaviors in clonal microcolonies. These studies highlight the emergence of spatial gradients of nutrients and metabolites, which can lead to niche specialization and division of labor within microbial populations. Overall, microfluidics provides a powerful tool for understanding the complex interactions and behaviors of microorganisms in natural environments, offering insights into their ecological functions and responses to environmental changes.Microfluidics has revolutionized the study of microbial ecology by enabling the observation and quantification of microbial processes at the single-cell level, providing a high degree of control over environmental conditions. This review highlights recent advancements in microfluidic systems that have enriched our understanding of microbial life and communities. Key applications include: 1. **Single-Cell Responses to Environmental Fluctuations**: Microfluidic devices, such as the 'Mother Machine,' allow for precise control over environmental shifts, enabling the study of bacterial responses to temporal fluctuations. These studies reveal phenotypic heterogeneity among individual cells and how it affects population-level responses. 2. **Navigation in Spatially Heterogeneous Environments**: Microfluidics is used to study microbial chemotaxis in complex environments, including oceanic and soil habitats. Devices with source-sink designs generate chemical gradients, allowing researchers to track bacterial movement and interactions with environmental cues. Studies have shown that bacteria adapt to spatial gradients through chemotaxis, thermotaxis, and aerotaxis, influencing their survival and ecological roles. 3. **Two-Dimensional Microcolonies and Collective Behaviors**: Microfluidic platforms, such as the Family Machine, enable the long-term observation of metabolic heterogeneity and collective behaviors in clonal microcolonies. These studies highlight the emergence of spatial gradients of nutrients and metabolites, which can lead to niche specialization and division of labor within microbial populations. Overall, microfluidics provides a powerful tool for understanding the complex interactions and behaviors of microorganisms in natural environments, offering insights into their ecological functions and responses to environmental changes.