Most organisms on earth depend on the energy from the sun. Sunlight is also an important coordinator of life’s timers. Animals take important cues for proliferation, activity, feeding, or sleep from changing light conditions. These rhythms also exist in humans — as changing light conditions across the year can strongly impact human mood and psychology.
Part of the natural light from the sun we are exposed to consists of ultraviolet (UVA and UVB) light, a short-wavelength part of the spectrum that is largely missing in artificial lighting. So far, most research on seasonal cycles has focused on day length. “In contrast to previous assumptions, we discovered that, in addition to day length, the intensity of UVA light influences the seasonal responses of the bristle worm Platynereis dumerilii,” explains first author Vinoth Babu Veedin Rajan, who carried out the work during his PhD in the Tessmar-Raible lab. MORE