A) Rates of primary productivity for reef macroalgal and sediment microalgal communities will be determined from measurements of oxygen release (and/or CO2 consumption) collected from reef (3x) and bare sand/microphytobenthos (3x) communities using benthic chamber incubations. B) Nutrient enrichment experiments - response of macroalgae will be measured in terms of N assimilation in algal tissue, changes to species composition and changes in abundances. The response of consumers (abundance and other aspects of population dynamics, biomass, feeding biology and fecundity) will also be investigated, using video for mobile (fish) grazers, and quadrat sampling for less mobile grazers (eg. gastropods on reefs, urchins in sediments). Variations in the isotopic composition of the algae and consumers will be used to assess nutrient exposure and subsequent energy flow pathways into secondary production.
