To reduce stress, an orderly alternation of dark and light is required by most animals which gives them alternate periods of activity and rest. Continuous long days cause the birds to breed themselves to exhaustion.
Several exhibits have very low light intensity.
These exhibits display either nocturnal animals, such as the octopus which would hide in brighter light, or deep water fish which live in permanent or near-permanent darkness. The light intensity in most exhibits is too low to support much plant growth. This is because the light intensity required to grow plants would be too bright in most instances for people viewing the exhibit as well as many of the animal specimens in the exhibits. Therefore, most of the large seaweeds and grasses on display are plastic replicas. These diatoms are not highly regarded dietary items and are scrubbed off of windows and rocks.