hermatypic

hermatypic Normally refers to reef-building corals.

造礁的通常指会造礁的瑚。

Reef-building or hermatypic corals are only found in the photic zone (above 50 m depth), the depth to which sufficient sunlight penetrates the water for photosynthesis to occur.

大瑚必须在大洋的透光层（水深不到50米）中生长，这里瑚内部共生的单细胞的虫黄藻能够进行光合作用。