The reason is that darknessâor, to put it the other way, the absence of lightâstimulates the production of a hormone, melatonin, from its immediate precursor, the neurotransmitter serotonin. Like serotonin, melatonin plays important roles in our physical and mental well-being.
The five major ocean gyres. A gyre in oceanography is any large system of circulating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis effect; planetary vorticity along with horizontal and vertical friction, determine the circulation patterns from the wind curl (torque).
Gyre Facts. â¢ A Gyre is a naturally occurring vortex of wind and currents that rotate in a clockwise direction in the northern hemisphere and counter-clockwise in the southern hemisphere.These create a whirlpool effect, whose vortex moves more slowly at the center and that is where marine plastic debris collects. There are 5 major Gyres in the oceans worldwide, all of which are believed to contain plastic and persistent organic pollutants (POPs). These consist of carbon-containing chemical compounds that, to a varying degree, resist photochemical, biological and chemical degradation.