Sea Shore Antics

[Melanie]

Ive been to hot climates and noticed the waters are always very blue, whereas around the uk they are

always green. Is it a different colour water or because of the content... the lower visibility in uk?
thanks
Melanie

[Steve]

Hi Melanie

As everything is coloured to our eyesight by the different absorption and scattering properties of visible wavelength light, water is

no exception..... and it is blue.

Water has good absorption and poor scattering ability for the red (long wavelength) at one end of our visible light spectrum and it

changes towards the other end of the spectrum to having poor absorption and good scattering ability for blue (shorter wavelength).

So water itself absorbs red

so little is noticed and scatters blue so much is noticed (to our eyes).... blue!

Tropical waters appear this colour because there is little within the water to change

the colour. It is actually very nutrient poor.
In UK cooler temperate waters however, there are other factors to consider because it is nutrient rich and therefore

contains such things as plankton, inorganic particulates and dissolved matter, all of which also absorb and scatter light. It is the concentration of these within the UK

waters that give it the greenish colour (and poorer visibility)

steve