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Name: Mathew
Status: Student
Grade: 6-8
Location: FL
Country: United States
Date: April 2006


Question:
How come if you go to different areas of the ocean the water is different color? Example: Close to shore water is green then when you go 30 miles offshore the water is dark blue.



Replies:
Matthew,

There can be many reasons for different "colors" of ocean water or fresh water.

The sky condition can make a big difference, as a clear blue sky will be reflected by the water as a darker color, whereas a cloudy sky will be reflected as a lighter color.

The depth of the water changes how much light is reflected from the sea bottom below. For shallow water, such as near a beach, the light reflected from the sand below the water will make the water look lighter (thus green) than it will look if you are in deep water (where little or no light is reflected from the bottom, resulting in dark blue water).

Light is also reflected from the interior of the water also, and the color of whatever is in the water (seaweed, soil, suspended sand, etc.) will affect the color that you see from the water.

The Sun angle affects the water color also, as less light is reflected from the surface, bottom, and interior of the water near noontime than is reflected during early morning or evening. The water is likely to look darker around noontime.

David R. Cook
Climate Research Section
Environmental Science Division
Argonne National Laboratory


Not all of the oceans are even the same color, or even the same color in different places. Mostly this has to do with what is in the water. Near shore, deep currents push up considerable amounts of minerals from the seabeds, and microscopic life florishes. In deeper seas, although by no means devoid of life, the algeal blooms are not present, so there is a clearer view through the water. Different oceans have different mineral content as well, meaning some take on an almost teal appearence, while others may appear more greyish in color. I can tell you from expierience that I've seen every shade of blue imaginable (and a few I'd never imagined) in the Pacific ocean, depending on where I was, the weather, and the time of year.

Ryan Belscamper



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