Blue Light Effects in Marine Macroalgae

Abstract

The red, brown and green seaweeds, which together make up the marine macroalgae, constitute a taxonomically unorthodox and artificial collection of plants. They are united, however, by the range of habitats which they occupy — marine benthic sites from the upper intertidal to the lower limit of the photic zone in all optical water types [16] — and it is the variety of light climates that they experience in this habitat range [11] that makes their responses to light of particular interest. The diversity of photosynthetic pigments within this group of plants also indicates that the group has evolved different physiological solutions to at least one photobiological problem, and suggests that the photobiology of these plants would repay detailed study. Nevertheless, the investigation of nonphotosynthetic effects of light on marine macroalgae has been slow to develop and, although a wide range of blue light effects has now been reported, this is the first review to concentrate specifically and solely on the responses of seaweeds to blue light. Some of the responses have, however, been covered by recent reviews of photomorphogenesis in marine macroalgae [11, 20], and the blue light effects in one rather exceptional genus, the giant-celled green alga Acetabularia, are described elsewhere in this Volume by Schmid. Another macroalga which exhibits blue light effects is the siphonaceous chrysophyte Vaucheria, but this genus has been excluded from the present review, partly because most species are found in fresh or brackish waters rather than in strictly marine habitats, and partly because it was featured at the first Blue Light Conference [2].