Resumen: Identifying the microbial taxa that structure assemblages in response to local disturbances along the Chilean Patagonian coast is critical for understanding community reorganization and ecological risk in this vulnerable marine environment. Here, we examined benthic microbial interactions across sixteen sites spanning 42–44°S in the Inner Sea of Chiloé and adjacent fjord systems. Using co-occurrence network analysis, we characterized spatial interaction patterns and identified keystone taxa whose relationships with environmental variables may serve as ecological indicators. The presence of keystone taxa supports the concept of microbial “seed banks,” which sustain community stability and ecosystem functionality under stress. Networks revealed structured communities dominated by niche-specialist taxa, consistent with ecological processes of niche differentiation and environmental filtering.