Samples of two common macroalgal species (Sargassum mangarevense, Turbinaria ornata) are collected yearly from fringing, backreef, and reef crest sites at each of the sites (LTER 1 through LTER 6) around Moorea. CHN analyses of dried, ground samples of each individual are made using standard methods. CHN data are used to track sustained variation in nutrient availability. Water column nutrients in coral reef systems usually are low to undetectable and their inputs tend to be episodic and ephemeral. Using CHN contents of macroalgae allows the integration of nitrogen availability over a longer time period, in this case, over approximately 3 months.