from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of or relating to light.
- adj. Penetrated by or receiving light.
- adj. Designating or relating to the layer of a body of water that is penetrated by sufficient sunlight for photosynthesis: the photic zone of the ocean.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. of, related to, or irradiated by light; especially describing that part of the near-surface ocean is which photosynthesis is possible
from the GNU version of the Collaborative International Dictionary of English
- adj. Of or pert. to light; specif., relating to the production of light by the lower animals.
from The Century Dictionary and Cyclopedia
- Of or pertaining to those forms of radiation which are productive of luminous effects; relating to light.
- In phytogeography, well-lighted: designating the upper bright region of bodies of water in which the light is sufficiently intense for the normal development of microphytes. Correlated with dysphotic and aphotic.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. of or relating to or caused by light
Sneezing as the result of being exposed to a bright light-known as the photic sneeze reflex-is a genetic quirk that is still unexplained by science, even though it has intrigued some of history's greatest minds.
One and Three Photographs [Ety.] stands out within this series because it makes photography the subject of this inquiry and because the term used to verbally represent the photograph is "photic," which means of or related to light.
Along with genetic analysis of a variety of other traits (such as photic sneeze) Eriksson presented data on two novel regions significantly associated with hair curl, one close to the the abstract for details).
As in the case of all algae, cells below a minimum size (about a mm or so) are effectively neutrally buoyant, which would have been extraordinarily important, as they would otherwise sink into the sub-photic zone and die.
This is known as autosomal dominant transmission, so photic sneezing now has the irresistible scientific name of “autosomal-dominant compelling helio-opthalmic outburst,” the acronym for which is, of course, ACHOO.
Among other things, he asked those with photic sneezing (18 percent of the patients and 24 percent of the students) if they had any close relatives who reacted to sunlight the same way, and found that 80 percent of the sneezers said they did, compared to only 20 percent of the non-sneezers.
This strongly indicated that photic sneezing has a genetic component, and further studies have borne that out.
Sunlight can only penetrate to a depth of about 183 meters (m) (the photic zone).
Because photosynthesis is only possible in the photic zone and because the average depth of the oceans is about 3,800 m, most of the ocean is too deep to for photosynthesis to occur.
Deep ocean ecosystems rely either on the input of detritus (whose energy originally comes from the photic zone) or deep-sea vents.