The symbiosis between animals and algae is a general biological phenomenon observed in various animals such as coral and jellyfish. The host gives nutrients and carbon dioxide to the symbiotic algae, and the symbiotic algae  gives oxygen and photosynthetic products to the host. This is an efficient carbon neutral system in which symbiotic algae fix carbon dioxide emitted by host animals as blue carbon and supply it to the host as nutrition.

 Ushimado marine institute in Ushimado Marine Biological Laboratory has been studying the genome evolution and molecular interactions in animal-algal symbiosis using green hydra, a cnidarian like coral, and Praesagittifera naikaiensis, which can be collected in the Seto Inland Sea. Understanding the animal-algal symbiosis mechanism is expected to serve as a basis for environmental conservation and industrial use, as well as a model for achieving carbon neutrality.