The cells in oxygen-consuming producers, consumers, and decomposers then carry out aerobic respiration.
This process breaks down glucose other complex organic compounds and converts the carbon back to CO2 in the atmosphere or water for reuse by producers. This linkage between photosynthesis in producers and aerobic respiration in producers, consumers, and decomposers circulates carbon in the biosphere. Oxygen and hydrogen-the other elements in carbohydrates-cycle almost in step with carbon.