Final answer:
Photosynthetic primary producers, like plants and algae, use sunlight for energy production, while chemosynthetic producers, typically microbes near hydrothermal vents, use inorganic chemical reactions for energy. Both are forms of autotrophs, forming the base of their respective ecosystems' food webs.
Step-by-step explanation:
What differentiates photosynthetic primary producers from chemosynthetic primary producers is that each uses a different energy source. Photosynthetic producers, also known as photoautotrophs, such as plants, algae, and cyanobacteria, harness sunlight to synthesize their organic compounds. On the other hand, chemosynthetic producers (chemoautotrophs), like those found near deep-sea hydrothermal vents, utilize energy from inorganic compounds such as hydrogen sulfide, ammonia, or methane to produce organic matter.
In photic zones where sunlight is abundant, autotrophs conduct photosynthesis. Conversely, in dark environments of the ocean where light does not reach, such as near hydrothermal vents, chemosynthesis is the process by which certain microbes construct biomolecules. Chemosynthetic organisms are often extremophiles adapting to harsh conditions, and they form the basis of a unique ecosystem, serving as a primary energy source for various deep-sea creatures.