New York, Chicago and Houston,
some skyscrapers and other landmarks
now institute “lights out” programs
during bird migration seasons which
indeed are really welcome.
Light pollution and Human Health
Many environmentalists, naturalists,
and medical researchers consider
light pollution to be one of the
fastest growing and most pervasive
forms of environmental pollution.
Scientific research suggests that light
pollution can have lasting adverse
effects on both human and wildlife
health. Alteration of the circadian
clock can branch into other effects
besides sleep disorders. A team of
Vanderbilt University researchers
considered the possibility that
constant artificial light exposure in
neonatal intensive care units could
impair the developing circadian
rhythm of premature babies. One
study published in the 1 December
2005 issue of Cancer Research
implicated melatonin deficiency
in what the report authors called a
rational biologic explanation for the
increased breast cancer risk in female
night shift workers. The evidence
that indoor artificial light at night
influences human health is fairly
strong today. The effect of light
pollution on human health can be
given as:
1) Glare (bright light) affects on
human eyes by reducing contrast
sensitivity, colour perception and
ability to see contrast which affect
eye sight and also responsible for
accidents during night time.2) Disturbed circadian rhythm
(24 hours day-night cycle)
causing decrease cell regulation,
cardiovascular problems and
insomnia.3) Melatonin (hormone to reduce
tumour) which is produced onlyin darkness suppresses cancer and its lower production due to night light
lead increased incidence of cancer and also affects many other functions of
our body including sleeping cycle of human, obesity, stress, depression and
onset of diabetes, etc.Light Pollution and the Breeding
of AnimalsA team of animal biologists from the University of Glasgow and the Max
Planck Institute for Ornithology reported that the additional light from
artificial sources in the cities caused the city birds to perceive the days to
be longer by 49 minutes on average. This had an effect on the city birds’
photoperiod, the light fraction of a 24-hour day which organisms use to
time their daily and seasonal biology. As a result, the birds in early March
experienced the day length that their country counterparts experienced in late
March. The city birds’ perception that they were living at a later point in the
year caused them to reach sexual maturity in anticipation of breeding season
19 days earlier than the forest birds.The glowing night sky of the towns and cities causes nocturnal wildlife (flora
and fauna) around the world to experience a loss of their night ecosystem.Mammals, bats, raccoons, deer get affected by interfering their predator-prey
relationship. For amphibians, population reduction and decrease in body
weight of frogs and tadpoles (anurans) are observed. Similarly reproductive
behaviour of many insects such as fireflies, moths and night flying insects get
badly affected. Light pollution also affects zoo planktons, which are groups
of heterotropic small organisms and immature stages of larger animals found
within larger bodies of water. These are an integral component of the food
chain. As a result, daphnia are unable to feed on surface algae, causing algal
bloom that can kill off the lake’s plants while lowering the quality of water.Figure: Many of the orientation behaviour of the animals including the just hatched turtlesneScholar 0 vol 4 0 issue 4 45
LIGHT POLLUTION I SCIENCE