Main Page | See live article | Alphabetical index The photic zone is the depth of the ocean that is exposed to sunlight. The depth of the photic zone can be greatly affected by such things as turbidity and the season of the year. The depth of the photic zone is generally proportional to the level of primary productivity that occurs in that area of the ocean. The aphotic zone is that portion of the ocean that is exposed to no direct sunlight. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.