photic
/ˈfəʊtɪk/adjective
1- technical of or relating to light, especially as an agent of chemical change or physiological response〈技〉（与）光（有关）的（尤指致化学变化或生理反应的）。
1.1
- Ecology denoting the layers of the ocean reached by sufficient sunlight to allow plant growth【生态】（海洋）透光水层的：
an average depth for the photic zone is about 100 m.
透光水层平均水深大约是100米。