Article The need for Light & Photosynthesis

THE NEED FOR LIGHT

Almost all animals are dependent on light, aquarium fish are no exception. Many species rely on their sense of sight to feed and communicate, os use daylight to set their internal clocks, which govern many behavioral and biological processes. Light is vital for the healthy growth of living plants in the tank, and good illumination is necessary for showing fish at their best.

Note> The reflective hood is often equipped with more than one kind of fluorescent tube. The tubes must be long enough to illuminate the entire tank. An electronic timer will automatically switch the light on and off in a daily cycle.

Ordinary tungsten bulbs, suspended over the water, can be used to illuminate a tank. However, they emit large amounts of heat (which causes rapid water evaporation), their light spectrum does not match that needed by plants, and they cast an unattractive yellow pallor over the tank. Today's aquarists are much more likely to use fluorescent tubes, which run cooler, and can match the spectral qualities of natural light. The tubes are typically housed in a reflector hood, placed on top of the tank. The light housing also plays a useful role as a lid, preventing the escape of heat, moisture, and sometimes even leaping fish, while keeping pets and children's hands out of the aquarium.

PHOTOSYNTHESIS

Nearly all plants-terrestrial and aquatic-carry out photosynthesis. This process is vital to all life because it allows plants to manufacture sugars from which carbon dioxide and water, whiich they use as food.
The energy for photosynthesis comes from sunlight-but some wavelengths (colors) of light are more effective than others in energizing the process.

Note> Aquatic plants tank up carbon dioxide produced by fish and "fix" it into sugars. Oxygen given out by the plant as by-product of photosynthesis is used by the fish in respiration.

{In short tems..the fish provides carbon dioxide for the aquarium plant which the plant converts into Oxygen for the fish.}

Certain wavelengths of light are needed to promote photosynthesis. These wavelengths must be produced by any bulb or tube used to illuminate an aquarium.

(See Photo) Photosynthesis is most effective when plants are exposed to violet-blue and orang-red light.

 

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