What makes the ocean in tropical places so amazingly blue?

Question

take a look at these pics of whitsunday island

http://en.wikipedia.org/wiki/Whitsunday_Island

what makes the water so crystal clear and pure?

Answer 1

As funny as it sounds, the blue color that you see is the result of the lack of plankton in the water column. Water is an excellent filter of color (with blue being the spectrum that does the deepest with red being removed within the first 2 ft of water).

The greener the water, traditionally speaking, the more phyto-plankton is in the water column and hence the more productive the water can be (depending on various food chains being present).

Answer 2

The ocean appears blue because blue light is scattered by the water with the red end of the spectrum being absorbed more rapidly.

Tropical waters tend to be oligotrophic, that is, low in nutrients, thus there is very little plankton growth. The plankton are what give the water a greenish color.

How blue the water appears also depends on depth and bottom type.

Blue water can also be found in non-tropical latitudes when you are outside of the direct nutrient inputs from the coast.

Tropical water actually has lots of plankton (much less relative to other areas) and under the right conditions, blooms can occur almost anywhere, changing the color of the water.

Answer 3

A better question is, "what makes the ocean in most places an icky green?" Algae or other microscopic life forms in the water I think.

Actually, I have seen pretty blue water at Catalina Island, off the coast of California near Los Angeles. All you need is reasonably clean water over a shallow, white sandy bottom.

Answer 4

Ocean / sea water reflects the sky. If the sky is blue the water will be blue.If the sky is dark the water will also be dark.

Water will be clear if there is no waves .If the waves are strong it will bring all sand and the water will look dirty.

Answer 5

it depends on what's on the bottom:

blue water = sand
green = seaweeds or rocks
black = saltwater silt
brown = freshwater silt (like in lakes and rivers)

also, the brown color is from a substance called tannis that comes from leaves and stuff rotting in the water

Answer 6

It is a combination of the type of sea life, pollution level, distance from shore and the reflection of the sky