Marine snow is made up of the decaying remains of plants and animals that once lived near the ocean’s surface. Marine snow also includes fecal matter, sand, soot, and other inorganic dust. The decaying matter appears white and fluffy as falls towards the ocean floor, which is why it is called “marine snow.” It can take weeks for a single particle to reach the ocean floor. Marine snow falls continuously and provides an important source of food for many deep-sea dwellers.