Answer : chemosynthesis and marine snow
Step-by-step explanation : 
- Chemosynthesis is a process in which an organism instead of utilizing the energy of sun utilizied another source of carbon such as methane for production of food.
 
- Since, in deep sea the sunlight is not able to penetrate there, instead of photosynthesis, chemosynthesis takes place.
 
- Marine snow is the process in which the upper layer of detritus falls down from the upper layer of water column. 
 
- Marine snow is considered to be an important source of food for organisms living at the bottom of the ocean. 
 - Thus, marine snow and chemosynthesis are the two processes that are an important source of food for deep sea organisms.