Final answer:
The process that does not directly contribute to carbon storage within sediment is cellular respiration, where living organisms release carbon dioxide into the atmosphere as a byproduct of metabolizing carbohydrates.
Step-by-step explanation:
The process in the carbon cycle that does not contribute directly to the storage of carbon within sediment is C. the formation of carbon dioxide through metabolism of carbohydrates. This process refers to cellular respiration, where living organisms, including plants and animals, convert carbohydrates into energy and release carbon dioxide as a byproduct. Unlike the other processes listed, which involve the physical deposition or transformation of carbon into long-term storage forms, cellular respiration simply moves carbon dioxide back into the atmosphere or waters, making it available for use by photosynthetic organisms rather than contributing to sediment storage.
Other processes mentioned, such as the accumulation of organic carbon from decaying organisms (A), the deposition of dissolved atmospheric carbon dioxide into oceans or other waters, which can eventually lead to sediment formation (B), and the formation of fossil fuels from terrestrial organisms under conditions of high heat and pressure (D), all relate to the actual sequestration of carbon into sediments or other long-term reservoirs. Therefore, these contribute directly to the long-term storage of carbon, unlike cellular respiration.