Sedimentary nitrogen uptake and assimilation in the temperate zooxanthellate sea anemone Anthopleura aureoradiata

► Anthopleura aureoradiata is abundant on mudflats and rocky shores in New Zealand. ► Sediment was ingested by the anemone and N transferred to its zooxanthellae. ► This nitrogen was insufficient to influence the N-status of the symbionts. ► Zooxanthellae on mudflats were more N-sufficient than those on rocky shores. ► This might result from high levels of ammonia in mud rather than particulate N.