We examined changes In the levels of dissolved inorganic nitrogen (DIN) during incubation experiments with 4 conspicuous sponge species from Caribbean coral reefs, mangroves, or seagrass beds (Chondrilla nucula, ?Pseudaxinella zeai, Oligoceras violacea, Plakortis halichondroides). DIN accumulation in the incubation water was detected for all the species, but no significant DIN concentration cha...