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).
Recent Examples of gyre from the Web. 1  That occasional, sudden-onset widening-gyre sensation. 2  Traveling by raft, Eriksen and Paschal make their way into the gyre the way that plastic garbage doesâpassively carried along by the current.