Silver electrodeposition at the air/water interface is found to yield
a hitherto unreported ring morphology, with silvery, quasi-2D rings al
ternating with black, 3D-like ones. This is attributed to oscillatory
accumulation/detachment cycles of hydrogen at the growing edge of the
deposit. With this morphology, the measured morphology diagram closely
resembles that of bacterial colony growth, indicating a similarity of
the underlying growth mechanism.