denitrification and anammox in tropical aquaculture settlement ponds an isotope tracer approach for evaluating n2 production脱氮和氨在热带水产养殖解决池塘的同位素示踪方法评估n2生产.pdfVIP

Denitrification and Anammox in Tropical Aquaculture Settlement Ponds: An Isotope Tracer Approach for Evaluating N2 Production 1 2 3 4 4 2 Sarah A. Castine *, Dirk V. Erler , Lindsay A. Trott , Nicholas A. Paul , Rocky de Nys , Bradley D. Eyre 1 AIMS@JCU, School of Marine and Tropical Biology, Australian Institute of Marine Science, Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, Australia, 2 School of Environmental Science and Management, Centre for Coastal Biogeochemistry, Southern Cross University, Lismore, New South Wales, Australia, 3 Australian Institute of Marine Science, Townsville, Queensland, Australia, 4 School of Marine, Tropical Biology and Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, Australia Abstract Settlement ponds are used to treat aquaculture discharge water by removing nutrients through physical (settling) and biological (microbial transformation) processes. Nutrient removal through settling has been quantified, however, the occurrence of, and potential for microbial nitrogen (N) removal is largely unknown in these systems. Therefore, isotope tracer techniques were used to measure potential rates of denitrification and anaerobic ammonium oxidation (anammox) in the sediment of settlement ponds in tropical aquaculture systems. Dinitrogen gas (N2) was produced in all ponds, although potential rates were low (0–7.07 nmol N cm23 h21) relative to other aquatic systems. Denitrification was the main driver of N2 production, with anammox only detected in two of the four ponds. No correlation