The primary source of energy in geochemical cycles is the Sun. Solar energy drives various processes that influence chemical reactions within ecosystems, such as photosynthesis in plants. During photosynthesis, plants convert solar energy into stored chemical energy in the form of glucose, providing the foundation for food webs. Additionally, solar energy impacts water cycles, influencing climate and weather patterns. Consequently, the sun's energy plays a crucial role in sustaining life and facilitating the movement of nutrients through different biogeochemical cycles that are vital for ecosystem health.