Do primary consumers always make up the first trophic level in a food web?

Primary consumers do not always make up the first trophic level in a food web. In some cases, such as in deep-sea hydrothermal vent ecosystems, primary production is supported by chemosynthesis rather than photosynthesis. In these systems, primary consumers are organisms that feed directly on the chemosynthetic bacteria or archaea that form the base of the food web.