Country: United States
Date: April 2006
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.
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
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.
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Update: June 2012