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Sea Shore Antics This forum of www.seashoreantics.com is to glean or discuss info on UK sea shore wildlife and their antics, beit what they do, where they do it and why when and how.
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administration Site Admin

Joined: 24 Oct 2004 Posts: 47 Location: Nearwater
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Posted: Mon Nov 22, 2004 1:21 am Post subject: Light absorption in water |
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The visible light to humans of red through to blue is absorbed in water according to its wavelength and so is absorbed at
differing rates relative to depth (being distance travelled).
Red (around 700nm) is greatest at being absorbed
Then Orange, Yellow, Green
Blue (around
460nm) is least absorbed
In littoral areas of the sea shore, this is significant in that at low tide the full intensity of the full visible spectrum is available (pending
weather and obviously daytime measurements) whereas the same area, as the tide rises, is gradually filtered of its intensity and therefore variations of the visible
wavelength become present.... Red, being the most effected.
Taking a sample UK tidal range of 5 meters in height and water quality with average visibility:
In
these conditions, the transmission of Red light is reduced to around the 0% at the 5 meter depth (based on a 70% reduction per meter)
1m = 70% of 100% =
70%
= 30% transmission remaining
2m = 70% of 30% = 21%
= 9% transmission remaining
3m = 70% of 9% = 6%
= 3% transmission
remaining
4m = 70% of 3% = 2%
= 1% transmission remaining
5m = 70% of 1% = 1%
= 0% transmission remaining
(all data rounded to
nearest%) |
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shelley

Joined: 22 Nov 2004 Posts: 7 Location: Plymouth
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Posted: Thu Nov 25, 2004 11:50 pm Post subject: |
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from full to zero is substantial variation... good observation.
Im off to add it to the things that effect the seashore environment bit,
thanks.
Shelley |
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