How do producers that live above thermocline make food?

Photosynthesis: Sunlight penetrates the ocean and is absorbed by phytoplankton and other photosynthetic organisms that live above the thermocline. These organisms use the light energy to convert carbon dioxide and water into organic matter through the process of photosynthesis.

Chemosynthesis: Some producers, such as certain types of bacteria, don't rely on sunlight for energy. Instead, they use chemical reactions to convert inorganic molecules into organic matter. This process, known as chemosynthesis, occurs near hydrothermal vents and other areas with high levels of dissolved minerals.