Light pollution had many negative affects on biotic organisms. The combination of sky glow, light trespass, and glare all affect humans. Sky glow prevents us from seeing the stars and has anger astronomers for decades. Light trespass can affect the secretion of the master hormone, melatonin, which is only produced in the presence of darkness. Light which is spilled into the windows at night from parkinglots, streetlights, floodlights, etc, can affect a person's sleeping cycle, behavior, and biological well-being. Glare from intense light can cause an annoyance which makes us avert our eyes from the light being scattered across the eye, or disabling, making it impossible to see at all due to the brightness of light.
Animals are affected as well. Light pollution has caused major problems for sea turtle, birds, frogs, and nocturnal animals. Sea turtle hatchlings are being found dead on beaches due to the inability to instinctively find the water from shore. They follow the artificial lighting along the coastline instead, and become dehydrated or killed by predators on land. The survival rate is also low for hatchlings if the female is unable to find a dark, quiet place to lay her eggs. She may lay them in inadequate places such as in the water or where predators can find the eggs.
other animals such as birds, inscets salamanders and frogs have shown to be negatively affected by artificial light pollution. Plants are also impaired as it messes with the phytochrome plant hormone which regulates germination and dormancy.