Experiencing the shortest day of the year at the Biodôme

Color lighting is combined with white lighting to mitigate the transition effect.
Credit: Space for Life (Jean-Philippe Gagnon)
Les éclairages de couleur sont combinés à l'éclairage blanc pour atténuer l'effet de transition.
  • Les éclairages de couleur sont combinés à l'éclairage blanc pour atténuer l'effet de transition.
  • Fin de journée tardive, il fait sombre à l'extérieur pendant que l'écosystème est en pleine lumière.
  • Installation dans l'écosystème de la Forêt tropicale humide, juste au-dessus de la verrière.
  • Début de séquence combinée dans l'Érablière des Laurentides.
  • Coucher de soleil à l'étang de castor dans l’écosystème de l’Érablière des Laurentides.
  • Crépuscule dans l’écosystème du golfe du Saint-Laurent.
Experiencing the shortest day of the year at the Biodôme

I’m part of a team of superheroes. Recently we were asked, with our superpowers, to make sure that the sun rises and sets at the right time!

The thing is, under the Biodôme roof there are five ecosystems, representing different places on the planet.

It goes without saying that our focus is on animal wellbeing and that the animals have specific needs. Unlike the animals in tropical zones, the length of whose days doesn’t vary much from one season to the next, the species who live at the poles require great variations. That fluctuation in the length of the day and the night, called photoperiod, makes it possible to synchronize the natural rhythms particular to different species’ biology. For example, extending the length of the day triggers the breeding period. In nature, that important stage in an animal’s life coincides with an abundance of food and resources. Springtime, when light is more and more present, provokes bud break in plants, the emergence of insects, and the movement of migrating animals. All these phenomena depend on one another.

At the Biodôme, since we have the tropics, the north and the south to simulate, we have to be extremely vigilant to prevent one environment from disturbing the others.

Natural sunlight is very powerful and can’t be reproduced. All sources of artificial light are only a supplement to give the illusion that the day is getting longer. With a view to conserving energy, we take advantage of natural light as much as possible.

Still, one of the greatest challenges is adjusting to December 21, the shortest day of the year. It’s at that moment that use of artificial light is most important. With modern technologies (our superpowers!), almost anything is possible. Since the photoperiod in the tropical ecosystem hardly varies, it’s quite simple to reproduce. Artificial lighting stays the same all year, and the Montreal summer slightly lengthens the days in June and July. You might think that the ecosystems of the Laurentian Maple Forest and the Gulf of St. Lawrence don’t cause too many problems. But as it happens, they’re a real headache! In wintertime, from November to February, hours of sunshine are fewer. However, we need to have light early in the morning for Biodôme employees and late in the evening for visitors. To simulate those days, around 6:00 a.m. we start very gradually by using a few orange low-intensity lights. Then the intensity increases, and an hour later, white light is gradually added. On the shortest day, December 21, the sun itself makes an appearance around 7:30 a.m. In harmony with our systems, sunrise takes about three hours before reaching 100 percent intensity. Late in the day, the opposite sequence comes to a close at 7:00 p.m. for the longest night of the year in these ecosystems.

Were you aware that the in the Biodôme’s subpolar worlds, we keep to the real photoperiod of the Arctic and Antarctic? Currently, in the Antarctic, the daylight period lasts about 18 hours.

The annual programming of the photoperiod is a complex challenge. In addition to those fluctuations in light we have to contend with these other places: access corridors, work areas, emergency exits, exhibition areas… All these zones, if not taken into consideration, could indirectly have an important effect on the expression of the animals’ behaviors.

Fortunately, our team of superheroes is on the case!

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