Spine title: Light & photosynthesis in aquatic ecosystems. Includes bibliographical references (pages 432-490) and indexes.

Concepts of hydrologic optics -- Incident solar radiation -- Absorption of light within the aquatic medium -- Scattering of light within the aquatic medium -- Characterizing the underwater light field -- The nature of the underwater light field -- Remote sensing of the aquatic environment -- The photosynthetic apparatus of aquatic plants -- Light capture by aquatic plants -- Photosynthesis as a function of the incident light -- Photosynthesis in the aquatic environment -- Ecological strategies. Penetration of light into aquatic ecosystems is greatly affected by the absorption and scattering processes that take place within the water. Thus within any water body, the intensity and colour of the light field changes greatly with depth and this has a marked influence on both the total productivity of, and the kinds of plant that predominate in, the ecosystem. This study presents an integrated and coherent treatment of the key role of light in aquatic ecosystems. It ranges from the physics of light transmission within water, through the biochemistry and physiology of aquatic photosynthesis, to the ecological relationships which depend on the underwater light climate.