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Where does blue come from naturally?

Where does blue come from naturally?

Blue is one of the primary colors and it can be found abundantly in nature. The blue color we see is a result of selective absorption and reflection of light waves. When white light shines on an object, certain colors are absorbed while others are reflected back to our eyes. The reflected color is what we perceive. Blue is a short wavelength color that lies between green and violet on the visible spectrum. There are many natural sources that contain blue pigmentation and exhibit the blue color.

The sky

One of the most common associations with the color blue is the daytime sky. On a clear day, the sky appears as a light blue color. This is due to Rayleigh scattering of sunlight by the molecules in Earth’s atmosphere. The nitrogen and oxygen molecules scatter blue wavelengths more than other colors, making the sky look blue. At sunrise and sunset, the light has to travel farther through the atmosphere so more of the blue light is scattered away, leaving behind the longer wavelengths of orange and red.

Water

Large bodies of water often appear blue in color. This is again caused by the way light interacts with water molecules. The water absorbs long wavelength colors like red and reflects short wavelength blue. Impurities in water can also influence its color and make it appear more green or brown. But generally, clean, deep oceans and lakes transmit blue light back to our eyes. Some examples are the Blue Lakes in New Zealand, the Blue Lagoon in Iceland, and the deep oceans.

Blue flowers and plants

Many flowers and plants naturally exhibit blue coloration due to anthocyanin pigments. Anthocyanins reflect blue and purple light. Some examples of blue flowers are:

Flower Scientific Name
Bluebell Hyacinthoides non-scripta
Cornflower Centaurea cyanus
Forget-me-not Myosotis
Morning glory Ipomoea
Iris Iris spp.
Hydrangea Hydrangea macrophylla

Other blue plants include blue spruce, blue fescue grass, and some varieties of blue hosta.

Insects

Some insects like butterflies and beetles have blue coloration on their wings and bodies. This is also caused by structural colors, where microscopic structures on the insect wings scatter blue light. Some examples are blue morpho butterflies, blue damselflies, blue dragonflies, blue weevils, and blue ground beetles. The bright blue color serves as a warning signal to predators that these insects may be toxic or distasteful.

Birds

There are many species of birds that have blue feathers. The blue color comes from light scattering by the feather barbules. Some examples of blue birds include:

Bird Scientific Name
Blue jay Cyanocitta cristata
Bluebird Sialia
Indigo bunting Passerina cyanea
Blue penguin Eudyptula minor
Mountain bluebird Sialia currucoides
Blue-footed booby Sula nebouxii

The blue color helps birds with mate selection and identification. Some birds like blue jays also use their blue feathers for communication.

Amphibians

Some species of frogs and salamanders have blue coloration. For example, the blue poison dart frog, the blue-spotted salamander, and the endangered blue-tailed mole salamander. These amphibians get blue pigments from their diet and environment. The blue color serves as a warning to predators about the toxicity of the amphibian’s skin.

Reptiles

Certain lizards, snakes, and turtles have blue coloration. Some examples are the blue spiny lizard, the blue racer snake, and the eastern blue-tailed skink. The blue color is produced by chromatophores in the skin containing pigments like melanins and carotenoids. In some lizards like blue-tongued skinks, the blue color plays a role in mating displays and territoriality.

Fish

Many species of fish are blue due to wavelengths absorbed and reflected by their skin. Damselfish, mandarinfish, blue tang, and neon tetra are good examples. The blue color provides camouflage in the aquatic environment. Some fish like blue-streak cleaner wrasse use their blue stripes to signal to other fish that they offer cleaning services!

Minerals

Some minerals and gemstones exhibit blue coloration. Examples include:

Mineral Composition
Sodalite Aluminosilicate mineral
Azurite Copper carbonate hydroxide mineral
Blue quartz Silicon dioxide
Blue lace agate Chalcedony quartz
Blue titanium quartz Silicon dioxide with titanium
Blue john Fluorite
Blue beryl Beryllium aluminum cyclosilicate

These minerals derive their blue color from trace elements like iron, titanium, copper, and aluminum that produce brilliant blue crystals.

Blue in animals

Blue coloration serves different functions in the animal kingdom. Some key roles include:

  • Camouflage – Blue provides camouflage against blue surroundings like the sky, water, or plants. This helps animals hide from predators or prey.
  • Communication – The blue color acts as a visual signal for mating, marking territory, or warning off rivals and predators.
  • Thermoregulation – In some insects and amphibians, blue coloration helps regulate body temperature.
  • Protection – Through Batesian mimicry, some animals mimic the blue coloration of toxic species to avoid predation.

Blue in plants

Some functions of blue coloration in plants include:

  • Attracting pollinators – Blue flowers attract more bee pollinators.
  • Preventing overheating – Blue wavelengths are strongly scattered by plant surfaces, preventing over-absorption of heat.
  • Protection – Blue anthocyanin pigments act as antioxidants and protect plant tissues from damage.
  • Signaling – Blue fruits signal ripeness to seed dispersers.

Conclusion

In summary, there are diverse natural sources that exhibit blue coloration including the sky, water, minerals, plants, and animals. The physical and optical properties of materials, along with the presence of pigments, lead to the absorption and reflection of short blue wavelengths of light. Blue serves many important functions across species related to light interaction, visual communication, camouflage, thermoregulation, and protection. So next time you come across something blue in nature, think about how its unique color came to be!