What causes the colour of ocean water?

The colour of ocean water is primarily determined by the absorption and scattering of sunlight. Water absorbs colours at the red end of the light spectrum while scattering blue light, which gives the ocean its characteristic blue appearance. Factors such as algae, sediments, and dissolved organic matter can alter the colour, making it appear green, brown, or even red. Regions with high phytoplankton concentrations often exhibit greenish hues due to the chlorophyll they contain. These variations reflect the complex interplay of light and marine components.