Ocean particle accumulation has long been understood as the result of chance collisions and adhesion. But an entirely different and unexpected phenomenon is at work in the water column. Like so many discoveries, this one began accidentally. A graduate student intended to show a favorite parlor trick -- how spheres dumped into a tank of salt water will "bounce" on their way to the bottom, as long as the fluid is uniformly stratified by density. But the student in charge of the experiment made an error in setting up the density of the lower fluid. The spheres bounced and then hung there, submerged but not sinking to the bottom.