What are the two ways that organisms on the bottom of deep sea food chains acquire energy?

The two ways by which organism on the bottom of  the deep sea food chain acquire energy is through CHEMOSYNTEHSIS AND MARINE SNOW.
Chemosynthesis is the process by which some organisms synthesize organic compounds typically in the absence of sunlight by using energy derived from chemical reactions that involved inorganic chemicals. Marine snow on the other hand refers to the falling of organic materials from the upper part of the ocean water to the ocean bottom. Such materials are usually dead and decaying plants and animals from the upper part of the ocean.