Setal Comb Feeding Vortex Close-Up

You are suspended at the outermost margin of a feeding vortex generated by the rhythmic beating of a copepod's maxillary appendages, a current so precisely engineered that the surrounding water bends into laminar arcs converging on a mouth you cannot yet see. Before you, filling every plane of your visual field, rises the setal comb of *Temora longicornis* — ranks of chitinous filaments two to five microns in diameter, each one geometrically spaced from its neighbor to form apertures calibrated at the micron scale, wide enough to pass dissolved molecules freely while retaining phytoplankton cells, the whole lattice transmitting diffuse blue-black ambient light through its semi-transparent walls until each filament glows like amber fiber-optic glass, self-luminous and warm against the absolute cobalt darkness behind it. Caught mid-passage between two adjacent setae, a *Chaetoceros* chain — three silica-walled diatom cells in series, their lateral glass spines still projecting outside the comb, the structure bowed slightly under hydrodynamic pressure — records the precise instant when biological predation operates at the threshold between fluid dynamics and solid contact, the copepod's appendage musculature pulsing with slow contractile waves visible as traveling shadows behind the amber glow. Around you, diatom frustule fragments and collapsed dinoflagellate husks drift on identical arcing trajectories, fellow particles in a flow field that at this Reynolds number feels less like water than like a medium with memory, directing everything it carries toward a single predetermined destination.