Deposition and cycling of carbon and nitrogen in carbonate mud of Arlington and Sudbury Reefs, Great Barrier Reef

This study focused on the dynamics of carbon and nitrogen in carbonate mud from two northern GBR reefs (Arlington and Sudbury).Rates of mineralization based on net Total CO2 production ranging from 17 to 39 (mean=23) mmol C/m2/d. The overall ratio of O2:CO2 flux was 1.3, close to the Redfield ratio, implying that most of the organic matter that was mineralized was algal. Sulfate reduction and denitrification rates were estimated; there was no measurable methane production. Samples were analysed for sediment grain size and percentage silt, sand and clay, water content and for determination of total carbon, total nitrogen, total organic carbon and other elements (P, Ca, Mg, Sr, S and Fe).Mass sediment accumulation rates were calculated.Solute fluxes and fluxes of dissolved Fe, Mn and ammonium across the sediment-water interface were measured.Porewater was analysed for Cl, S, Ca, Fe, Mn, Mg and Sr, and saturation states for calcite and aragonite were calculated. This research was undertaken to document pathways of carbon and nitrogen cycling within the lagoons of coral reefs from the northern GBR. This is a companion paper to:Alongi DM, Trott LA and Pfitzner J (2007) Deposition, mineralization, and storage of carbon and nitrogen in sediments of the far northern and northern Great Barrier Reef shelf. Continental Shelf Research 27: 2595-2622.andAlongi DM, Trott LA and Pfitzner J (2008) Biogeochemistry of inter-reef sediments on the northern and central Great Barrier Reef. Coral Reefs 27: 407-420.This study focused on the flow of carbon and nitrogen in sediments of the far northern and northern sections of the Great Barrier Reef (GBR) continental shelf.