Ocean Regions: Blue Water - Characteristics

Another way to describe ocean zones is by the amount of light they receive. The topmost layer is called the euphotic zone and is defined by how deeply photosynthetic life can be found. Below this is the dysphotic zone, where light can be measured, sometimes as deeply as a kilometer down, but is too faint to support photosynthesis. From the lower boundary of this zone and extending all the way to the bottom is the aphotic zone, where no light ever passes, and animals have evolved to take advantage of other sources of food. One such environment is hydrothermal vent communities.