QUANTUM EFFICIENCY AND PHOTOSYNTHETIC PRODUCTION OF A TEMPERATE TURF ALGAL COMMUNITY

A preliminary investigation of the production and photosynthetic effic iency of a temperate, sub-tidal, turf algal community using in situ me asurements of photosynthesis and respiration is reported; Results indi cated that temperate turfs have high biomass specific productivity, bu t are less productive on an areal basis than either the surrounding;ma cro-algal community or their tropical counterparts. Net 24 h productio n ranges between 12 and 78 mmol O-2 m(-2)d(-1) (corresponding to a car bon fixation rate of 0.1-0.9 g C m(-2)d(-1)). Inefficient use of the a vailable substrata, due to the early successional nature of these comm unities, is considered to be the cause of this low productivity. A qua ntum efficiency of 0.034 mu mol O-2 mu mol photons(-1) and a sub-satur ating light itensity of 134-210 mu mol photons m(-2)s(-1) indicate tha t photosynthetic saturation was easily achieved and suggests that self -shading in the turf community was not significant.