13.3 Energy in Ecosystems Almost all producers obtain energy from sunlight. Photosynthesis is a process where producers use sunlight as an energy source. 6H 2 O + 6CO > C 6 H 12 O 6 + 6O 2 Chemosynthesis is a process where producers (prokaryote -bacteria) use chemicals as an energy source. 6CO 2 + 6H 2 O + 3H 2 S > C 6 H 12 O 6 + 3H 2 SO 4
