The primary source of energy in most ecosystems is sunlight. Photoautotrophs, such as plants, algae, and photosynthetic bacteria, capture solar energy through photosynthesis and convert it into chemical energy stored in organic compounds. This energy then flows through the ecosystem via food webs, supporting herbivores, carnivores, and decomposers
. While some ecosystems, like deep-sea hydrothermal vent communities, rely on chemical energy from inorganic molecules through chemosynthesis, these are exceptions. The vast majority of ecosystems depend on sunlight as their fundamental energy source
. In summary, sunlight drives the energy flow in most ecosystems by enabling primary producers to synthesize organic matter, which sustains all other organisms in the food chain
