Objective Microbial community in sediment plays an important role in maintaining the balance of pond ecosystem. The present research aimed to explore the characteristics and seasonal variation of carbon and nitrogen metabolism of microorganisms in sediment of high-density tilapia pond.

Method Sediment samples were collected during the aquaculture season, and the contents of nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and total nitrogen in sediment were analyzed. The average well color development (AWCD) of microbial metabolism of substrates containing both C and N, containing both C and P and containing C only was analyzed by Biolog-ECO plates.

Result The contents of total nitrogen and ammonia nitrogen in pond sediment in July and October were significantly higher than those in April. The microorganisms in the sediment could use substrates containing C only, including β-methyl-D-glucoside, pyruvic acid methyl ester, D-galacturonic acid, tween 80, D-mannitol and D-cellobiose, substrates containing C and N, including L-asparagine and N-acetyl-D-glucosamine (AWCD > 0.5), and substrates containing C and P, including D, L-α-glycerol phosphate and glucose-1-phosphate (AWCD < 0.5). 2-hydroxy benzoic acid, itaconic acid and α-ketobutyric acid could not be utilized. In April, AWCD of substrates containing C and N and substrates containing C only was higher than those in July and October. AWCD of substrates containing C and N, and substrates containing C only was positively correlated with nitrate content in sediment.

Conclusion Biolog-ECO plate technology could be used to analyze nitrogen use index of sediment microorganisms for evaluating nitrogen removal capacity of microbial community in sediment.