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Phosphorus and nitrogen in coral reef sediments
Author(s) -
Entsch Barrie,
Boto Kevin G.,
Sim Robin G.,
Wellington John T.
Publication year - 1983
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1983.28.3.0465
Subject(s) - algae , sediment , environmental chemistry , phosphate , nutrient , reef , phosphorus , ammonium , halimeda , benthic zone , arsenate , coral reef , nitrogen , carbonate , chemistry , oceanography , geology , botany , ecology , biology , arsenic , paleontology , organic chemistry
The occurrence of P and N in the sediments has been investigated on Davies Reef in the central region of the Great Barrier Reef Complex. Concentrations of inorganic P and N in the water were typical of nutrient‐depleted tropical surface water, Carbonate sediments were found to contain a uniform pool of P (300 ppm by wt), principally in the form of inorganic phosphate. The interstitial water of the surface layer of sediment contained micromolar concentrations of inorganic P and even higher concentrations of inorganic N, principally as ammonium. These nutrient concentrations should allow high rates of uptake of N and P by epilithic algae. Arsenate concentrations were considered too low to compete significantly with the uptake of available phosphate into algae. The presence of ammonium and soluble P was associated with anaerobic redox potentials in the sediments just below the surface. Soluble phosphorus was in equilibrium with a small, rapidly exchangeable fraction of the sedimentary pool of inorganic phosphate. Analyses of P in growing tips of Halimeda and corals (which supply more than half of reef sediments) suggested that the skeletons provide a biological mechanism for the replenishment of at least some of the sedimentary pool. Ratios of C:N:P for a selection of benthic algae were used as a preliminary indicator of their N and P status.