Understanding the processes that connect ocean physics and biogeochemistry to living marine resources and top predators is of great scientific and societal value, and will benefit from cross-ecosystem comparisons. In marine ecosystems, zooplankton and euphausiids (krill) represent a key link between primary production and higher trophic level species, such as pelagic fishes, marine mammals and seabirds. In theory, ecosystem hotspots are thought to be driven by bottom-up biophysical processes influencing enrichment of nutrients, their concentration and retention, leading to sustained aggregations of mid and high trophic level species.  However, in regions dominated by a strongly advective ocean circulation (e.g., coastal upwelling systems), the formation and persistence of ecosystem hotspots may be decoupled in space and time from primary production and nutrient sources. In this session, we welcome contributions from various marine systems involving observing and modeling approaches (or a combination of both) to elucidate how scales of physical advection combine with those of biological processes to sustain ecosystem hotspots. Of special interest are studies that provide a mechanistic understanding of the fundamental biophysical processes that control marine life aggregations at various spatial and temporal scales, and offer insight into their past, present and future variability in marine ecosystems worldwide.