Summit in Cobalt Current

The AUV drifts just above a wave-scoured basalt summit, its sensors reading a steady thermocline-driven current as thousands of horse-eye jacks *Caranx latus* surge past in a single coordinated mass — flanks flashing silver-cobalt in the intense tropical midday light that still reaches this depth with almost undiminished force. This is the sunlit epipelagic realm where photosynthetically active radiation penetrates fully, fueling the plankton drift that accumulates along seamount ridges and transforms submerged volcanic topography into biological hotspots: the summit acts as an obstacle forcing nutrient-rich water upward, concentrating prey and drawing every tier of the pelagic food web into alignment. Silky sharks *Carcharhinus falciformis* work the current seam with hydraulic efficiency, their fusiform bodies angled precisely into flow, exploiting the confusion and compression at the shoal's trailing edge, while rainbow runners *Elagatis bipinnulata* knife through the periphery in streaks of green-gold — secondary predators occupying the productive middle of the water-column hierarchy. Below the AUV, encrusting coralline algae and low gorgonians grip the exposed basalt, testament to a substrate perpetually sandblasted by current, more open-ocean seamount than sheltered reef. The water is a lens of extraordinary clarity, god rays threading down from a bright surface barely thirty-five meters overhead, yet the cobalt blue dissolving beyond the ridge carries the unmistakable psychological weight of immense open-ocean volume pressing in from every direction.