Zooxanthellaceae

Zooxanthellaceae is a family of dinoflagellate algae. These single-celled organisms are characterized by their photosynthetic capabilities, meaning they can produce their own food using sunlight. A defining feature of zooxanthellae is their symbiotic relationship with various marine invertebrates, most notably corals, but also including anemones, jellyfish, and some mollusks. Within these host organisms, zooxanthellae reside in specialized cells.

The symbiosis is mutually beneficial. The zooxanthellae provide their host with a significant portion of their energy requirements through photosynthesis, supplying up to 90% of the energy needed for survival, growth, and reproduction. In return, the host animal provides the zooxanthellae with a protected environment and essential nutrients, such as carbon dioxide and nitrogenous waste products, which are crucial for photosynthesis. This partnership is fundamental to the existence of coral reefs, which are vibrant ecosystems built by coral polyps that rely heavily on their zooxanthellae partners. The vibrant colors often seen in corals are also due to the pigments of the zooxanthellae. When environmental conditions become stressful, such as rising sea temperatures, corals can expel their zooxanthellae, a phenomenon known as coral bleaching.