Environmental perturbations induced by natural disasters are major drivers of massive biodiversity collapse and assemblage shifts throughout the stratigraphic record. Whether on a global or local scale, the severity of these impacts generally increases with closer proximity to the source. In this study, we examine how multiple, repetitive localized environmental perturbations driven by volcanic activity alter local marine biotic constituents over the past 5,000 years. Using core data collected from the SO 299/2 expedition adjacent to the Krakatau volcano, we record the vertical sedimentary succession and subsequent biotic shifts, observed in benthic and planktonic foraminiferal assemblages. Lithologically, we distinguish multiple volcanic events, represented by the occurrence of repetitive tuffaceous/tephra layers interbedded with clay and sandy deposits. Within the foraminiferal record, specific taxa, such as juvenile Globigerina, Ammonia spp., the symbiont-bearing group, as well as shallow water taxa (e.g., Amphistegina, Operculina, Asterorotalia) and agglutinated benthic foraminifera, exhibit fluctuating pulses that closely correspond to the presence of ash layers. Additional signatures of ash-fall events are represented by sudden spikes in the planktonic foraminiferal percentage, alongside clear shifts favoring stress-tolerant taxa over sensitive taxa. Our results indicate potential water column alterations during the early stages of volcanic eruptions, which caused the mass mortality of juvenile planktonic foraminifera, followed by blooms of opportunistic taxa in the post-eruption environment. By coupling these biological and environmental shifts, we delineate four distinct evolutionary stages of the Krakatau complex, providing a baseline for future subaqueous studies in the region.