crab works
gentle touch of the retreating high tide waves reshuffles sand particles, covering them with thin coating of edible particles and leaving smooth blank surface for the sand bubbler crabs artwork. crabs appear out of their burrows as soon as the tide recedes. they eat organic matter from the sand creating geometrical patterns of clean sand bubbles. they have to work fast when the sand is wet and the tide is low. when the tide rises, again, crabs hide in their burrows with some air to breathe, and preparing for the next tide cycle.