ABSTRACT
Introduction The reflected surface colour of the ocean, whether seen from the deck of a ship or measured by an orbiting satellite, provides information about the contents, and processes, immediately below. Many of these near-surface processes, ranging from the absorption of red light by chlorophyll to the multihued visual signalling of reef fish, are dependent on colour. Interactions deep below the surface are also affected by colour; indeed, the colours of the animals caught in a research trawl give a good indication of the depth from which they have come. ‘Colour’ itself is a rather subjective concept; its perception is critically dependent upon both the light conditions of the environment and the visual systems of the observer. A more objective assessment requires knowledge of the spectral distributions of ambient, reflected, and absorbed light11.
