Dizon, Romeo M.Yap, Helen T.2025-06-231999-07Dizon, R. M., & Yap, H. T. (1999). Short-term responses of coral reef microphytobenthic communities to inorganic nutrient loading. <i>Limnology and Oceanography, 44</i>(5), 1259–1267. https://doi.org/10.4319/lo.1999.44.5.12590024-35901939-559010.4319/lo.1999.44.5.1259https://hdl.handle.net/20.500.14697/585The responses of coral reef flat microphytobenthos to short-term exposure to elevated levels of inorganic nitrogen (N) and phosphorus (P) were investigated in 1994 and 1995. Sand samples collected from the reef flat were maintained over 7 d in triplicate cultures with N-enriched (100 µM NO3), P-enriched (10 µM PO4), and ambient seawater. A fourth experiment used a treatment of combined N and P enrichment. The sediment samples were assessed for chlorophyll a (Chl a) content and photosynthesis-irradiance (P-I) responses. P-I curves, constructed from area-and Chl a-specific metabolic rates, showed consistently higher maximal rates in the nutrient enriched samples. Sediments exposed to enhanced levels of N exhibited the highest Chl a content while both N- and P-enriched samples showed increased photosynthetic yield. Very little depletion of nutrients in the water column was detected over time in the batch cultures except in the N:P-enriched treatments where nutrient values dropped to near-ambient levels. Results from these experiments point to N and P colimitation in tropical carbonate sediments.enArticleSDG 14 - Life below waterinorganic nitrogenphosphorussediment analysissedimentmicrobenthos