A key result from the isolation chamber experiments [no light] was that the circadian clock runs slow, taking about 25 hours to complete its cycle. Obviously, a 25-hour body clock would be quite useless as a predictor of daily environmental change, and so the search for zeitgebers (http://en.wikipedia.org/wiki/Zeitgeber) began.
Although life is very sparse at these depths, black smokers are the center of entire ecosystems. Sunlight is nonexistent, so many organisms — such as archaea and extremophiles — convert the heat, methane, and sulfur compounds provided by black smokers into energy through a process called chemosynthesis. More complex life forms like clams and tubeworms feed on these organisms. The organisms at the base of the food chain also deposit minerals into the base of the black smoker, therefore completing the life cycle.http://en.wikipedia.org/wiki/Black_smoker
Since God is light and we can't live without Him, we couldn't live without light.
I'm living without him just fine.
Unfortunately God makes blind people also and by that criteria they should all be depressed and have rickets. The few blind people that I know have/show no symptoms.
The answer I think is yes it is possible to live without natural light providing that substitute artificial lighting is provided. There are many indoor crops grown under artificial conditions and they grow well. Many deep cave animals also survive in complete darkness and now have no eyes as they have adapted to their situation.
The ecosystems around hydrothermal vents on the sea floor, ("black smokers"), have adapted to life without light...QuoteAlthough life is very sparse at these depths, black smokers are the center of entire ecosystems. Sunlight is nonexistent, so many organisms — such as archaea and extremophiles — convert the heat, methane, and sulfur compounds provided by black smokers into energy through a process called chemosynthesis. More complex life forms like clams and tubeworms feed on these organisms. The organisms at the base of the food chain also deposit minerals into the base of the black smoker, therefore completing the life cycle.http://en.wikipedia.org/wiki/Black_smoker
It's generally surprising to folks to discover that not all autotrophs are photosynthesizers. Over the last few decades, the importance of chemosynthesis has become increasingly obvious. We still don't know just how significant chemosynthesis is in the biosphere overall, but we do know that it is important. Chemosynthesizers are organisms which can produce carbohydrates by using chemical energy, rather than light energy. There was a time when a biology teacher could say with confidence that all ecosystems on Earth ultimately depended on light energy. We now know that this isn't true. Entire ecosystems exist along deep, midoceanic ridge zones supported not by photosynthesis, but by chemosynthesis. None of the energy in these ecosystems comes from light. There is a very interesting and reasonably well supported suggestion that the earliest life forms on the planet may have arisen in environments like these deep sea vent regions.http://www.cod.edu/people/faculty/fancher/Energy.htm
Chemosynthesis is the biological conversion of one or more carbon molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic molecules (e.g. hydrogen gas, hydrogen sulfide) or methane as a source of energy, rather than sunlight, as in photosynthesis. Large populations of animals can be supported by chemosynthetic primary production at hydrothermal vents...http://en.wikipedia.org/wiki/Chemosynthesis
I'm living without him just fine.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.ncpamd.com%2Fwinter_depression.jpg&hash=7beb58730053b6930867451b26f8f262)
http://www.ncpamd.com/winter_depression.jpgVitamin D Deficiency Is Associated With Low Mood
and Worse Cognitive Performance in Older Adults.
Wilkins CH, Sheline YI, Roe CM, Birge SJ, Morris JC.
Dept.Med.Div.Geriatrics and Nutritional Science, Alzheimer's Disease Research Center, the Dept.Psychiatry, Dept.Neurol., and the Div.Biostatistics, Washington Univ.School of Medicine, St. Louis, MO.
Background: Vitamin D deficiency is common in older adults and has been implicated in psychiatric and neurologic disorders. This study examined the relationship among vitamin D status, cognitive performance, mood, and physical performance in older adults.
Methods: A cross-sectional group of 80 participants, 40 with mild Alzheimer disease (AD) and 40 nondemented persons, were selected from a longitudinal study of memory and aging. Cognitive function was assessed using the Short Blessed Test (SBT), Mini-Mental State Exam (MMSE), Clinical Dementia Rating (CDR; a higher Sum of Boxes score indicates greater dementia severity), and a factor score from a neuropsychometric battery; mood was assessed using clinician's diagnosis and the depression symptoms inventory. The Physical Performance Test (PPT) was used to measure functional status. Serum 25-hydroxyvitamin D levels were measured for all participants.
Results: The mean vitamin D level in the total sample was 18.58 ng/mL (standard deviation: 7.59); 58% of the participants had abnormally low vitamin D levels defined as less than 20 ng/mL. After adjusting for age, race, gender, and season of vitamin D determination, vitamin D deficiency was associated with presence of an active mood disorder (odds ratio: 11.69, 95% confidence interval: 2.04-66.86; Wald chi(2) = 7.66, df = 2, p = 0.022). Using the same covariates in a linear regression model, vitamin D deficiency was associated with worse performance on the SBT (F = 5.22, df = [2, 77], p = 0.044) and higher CDR Sum of Box scores (F = 3.20, df = [2, 77], p = 0.047) in the vitamin D-deficient group. There was no difference in performance on the MMSE, PPT, or factor scores between the vitamin D groups.
Conclusions: In a cross-section of older adults, vitamin D deficiency was associated with low mood and with impairment on two of four measures of cognitive performance.
Am J Geriatr Psychiatry. 2006 Dec;14(12):1032-1040.
I read that children are going through pubity earlier because they don't go outside much.
Childhood obesity brings early puberty for girlshttp://www.newscientist.com/article/dn11307-childhood-obesity-brings-early-puberty-for-girls.html
12:41 05 March 2007
NewScientist.com news service
Phil McKenna
Increasing rates of childhood obesity may be responsible for a dramatic increase in early-onset puberty in girls, new research suggests.
Obese girls, defined as at least 10 kilograms (22 pounds) overweight, had an 80% chance of developing breasts before their ninth birthday and starting menstruation before age 12 – the western average for menstruation is about 12.7 years. Early-onset puberty could have serious health and social consequences, experts say, including increased incidence of teenage depression and of cancer in later life.
It seems to me that you would need to check that the diets of the two groups (suffering from dementia and not doing) were similar before you could make any progress attributing cause and effect here.
The association between Vit D and dementia is, no doubt, just what that study says, but is it because people with low Vit. D levels become demented or is it that demented people don't get enough vit D from their diet or, as RD suggests, from sunlight.