Seaweeds & Light: A Coloring Mystery

[LadiesMan]

1. Light at the blue end of the spectrum penetrates most easily underwater. Why are seaweeds often yellow-brown in colour?

Does anyone know why this phenomena occurs? Thanks

 

[dranseth]

Since light at the blue end of the spectrum penetrates most easily under water, it is these colours which are being absorbed by the pigments. What we see is the wavelengths that are transmitted or reflected. Therefore, it is the other end of the spectrum which we are seeing (red-yellow.)