CHARACTERISTICS OF PRODUCTION AND LIGHT ADAPTATION OF MARINE MACROPHYTE SPECIES COMMON TO THE SEYCHELLES

The characteristics of primary production (content of photosynthetic p igments, light response curves, and capacities of net photosynthesis) are studied in more than 20 species of algae and sea grasses inhabitin g various depths of littoral and sublittoral areas of the Seychelles s helf. Chlorophyll and phycoerythrin content, photosynthetic capacity, and the efficiency of weak light utilization in algae increased with i ncreasing depth of their habitat or the extent of their shadowing. Sim ilar responses to light were observed in red and green algae shadowed in aquaria, especially when inorganic N and P were added to the medium . However, the range of adaptive responses of the photosynthetic appar atus to changes in light for tropical sea grasses was narrower than th at for the algae from temperate zone waters. Algae of the genus Sargas sum had the highest photosynthetic capacity and the Halimeda species, the lowest.