Artists experiment with water colors in their paintings. Scientists experiment with water colors in bodies of water. Water is blue, but we’ve all noticed that it appears in many different shades of blue. Murky water is typically written off as dirty, but that’s not necessarily true. There are many reasons for water to look tropical turquoise, deep navy or any shade in between.
Water’s true colors
Water color is classified by its apparent color and its true color. The apparent color is what the water looks like naturally when it contains different particles. True color is evaluated after the sediments, algae and other particles are removed. River color is largely affected by the minerals it contains and soil runoff. You may have noticed that after strong storms, rivers often look dirtier and more brown from the extra runoff. Pollution and other contaminants can also change the color of river water.
50 shades of blue
Ocean waters around the world are distinguished by their color. Blue hues vary depending on a couple different factors. Oceans flow from west to east because of how the Earth rotates. These currents can cause upswelling in some places. Upswelling is when cold, deep sea water rises to the surface. When the water rises, it can carry sand, sediments and other materials with it, which makes the color murkier. Reefs work as natural barriers to prevent upwelling. This protects water from being stirred up by the waves, which is one way to keep it crystal clear.
In addition to the ocean’s natural movement, water clarity is affected by the sediments that rest underneath the surface. If the sand and silt are lightweight, they will float around more and make the water look darker. Heavier sand, seashells and other materials weigh more so they will stay on the ocean floor. Since the waves aren’t stirring these sediments to the surface, the water remains clear.
What lives on top of the water can have as much affect on color as what lies underneath the surface. Plankton are tiny organisms that float in both salt water and fresh water. They are a source of food for many larger animals. Where the water has a lot of plankton, it will look more green. Without plankton and other organisms, the water has more clarity. The clear, blue waters of the Caribbean, for example, don’t have many plankton. This means the water is a gorgeous blueish teal color, but it doesn’t have as many nutrients available for other fish to feed off of.
Sunlight also contributes to how blue the ocean looks. Water molecules absorb some of the sun’s rays. The light that is not absorbed gets reflected off the water’s surface. Deeper water absorbs more light and appears dark blue because the sun’s rays can’t reach the ocean floor. Shallow water makes it easier for light to travel to the bottom and reflect that surface, whether its coral or sand.
Beautiful like a rainbow
While water comes in many different shades, it always appears blue. There are some exceptions, however. Certain bodies of water are notable for their unusual color. The water in Laguna Colorada in Bolivia appears a startling shade of red. Pigmentation from red sediments and algae color the water in this salt lake, attracting large numbers of both tourists and flamingos. The top of Indonesia’s Kelimutu volcano features three distinct bodies of water, each one a different water color. The colors change unpredictably, but usually one of these lakes is blue, one is green and one is black or red. Scientists don’t have an official explanation for the water color changes, but it’s likely due to volcanic gas and other natural chemicals in the area. New Zealand is known for its breathtaking natural landscapes, and Lake Pukaki is one of those features. This body of water is a unique frosty blue color because glacial erosion fills it with tiny rock particles.
Glow in the dark water
Beaches with water that glows in the dark are stunning destinations. This phenomenon, called bioluminescence, occurs when certain kinds of algae are floating near the water’s surface. The algae emits glowing light when it’s swayed by the tide, jostled by the movement of fish or stirred by a passing boat. Glowing algae are found all over the world, but in Japan, the visual effect is not caused by algae. A unique Japanese creature called the firefly squid causes the luminous ocean water.
Water is identified as blue just like the grass is identified as green. These associations are fundamental to our understanding of colors, but they’re not always accurate. Water comes in many different shades of blue, gray, green and other colors. In art, water colors are changed by adding more or less pigment. In nature, water color is affected by a variety of factors.