When organisms die in an ocean biome, they are decomposed by bacteria like on land and become food for scavengers, such as sharks and crabs. Unlike on land, however, because many organisms live in the upper layers of water, death means that they tend to sink to the bottom, often a great distance from where they died. Thus, the fate of oceanic dead organisms is often more complex.
There is a great amount of variation in how organisms live and die between shallow, coastal waters and the deep ocean. In shallow waters, dead organisms often drop intact to the ocean floor. There, sharks, crabs and other invertebrates consume a carcass quite rapidly. If a shark is present, its bites often open the carcass for less powerful scavengers to access its organs.
In the open ocean, the deep sea floor means that it takes a great deal of time for a dead organism to travel from the surface. Nonetheless, the skeletons of many microorganisms and even some animal carcasses do make it to the bottom relatively intact. There, organisms like invertebrates and hagfish scavenge the bodies. However, there is a phenomenon called "marine snow," in which bodies, mixed with fecal matter and other debris, drop down on the ocean floor, supporting whole ecosystems of decomposers and scavengers despite the hostile, dark environment.