Effect of organic nitrogen and carbon mineralization on sediment organic matter accumulation in fish ponds

Abstract

In aquaculture, ponds with high loads of organic inputs, organic matter accumulates at the bottom over time. Uneaten feed, senescent phytoplankton and faeces are the principal sources of accumulated material, but quanti¢cations are scarce. The sedimented organic matter develops into a £occulent layer in which di¡erent processes transform the material into inorganic forms. A better understanding of factors in£uencing organic matter accumulation/decomposition in the sediment is needed to better understand and manage the dynamics of nitrogen in ¢sh ponds. In this study, the rate of mineralization of organic nitrogen and the nitrogen £ux between the sediment and the water column were measured. Organic matter accumulation in ¢sh ponds was quanti¢ed, and the data were used to construct, calibrate and validate a dynamic simulation model of organic matter deposition/decomposition in ¢sh ponds. The accumulating material consisted of dead phytoplankton, ¢sh faeces and uneaten feed. Through model calibration, the proportion of these materials in the total accumulated organic matter was determined. In the model, gross photosynthetic rate was estimated from an empirical relationship with feed input. After calibration, the model was validated using independent data. The model simulated well the concentrations of organic carbon and nitrogen in the sediments but it may be developed further, especially by considering the e¡ects of resuspension.

Nitrogen budget in integrated aquaculture systems with Nile tilapia and Amazon River prawn

“…The main sources are uneaten feed, feces, and dead plankton that sink by gravity action (Jimenez-Montealegre et al 2005). In addition, sediment has a buffering effect, which removes nutrients from the water and stores them (Chien and Lai 1988).…”

Burial fluxes and source apportionment of carbon in culture areas of Sanggou Bay over the past 200 years

“…Culture areas have higher carbon sequestration efficiency and intense biological activity, but are influenced greatly by human activities (Gao et al, 2008b). In aspect of organic matter in this area, related researches only focused on accumulation and distribution of carbon, nitrogen and other nutrients in surface sediments of aquaculture ponds (Steeby et al, 2004;Jiménez-Montealegre et al, 2005;Dahlbäck and Gunnarsson, 1981;Kaspar et al, 1985). The sedimentary records in these studies only lasted for 20 years; there was no record of carbon burial in natural breeding bay over hundred years (Giles et al, 2006;Liu et al, 2012).…”

The Use and Benefits of Bacillus Based Biological Agents in Aquaculture

“…Ammonia is a primary metabolic waste of fish and is excreted through the gills by bronchial diffusion. It is also produced by bacterial ammoniafication of uneaten food and faeces and is released from the mineralization of sediment [47][48][49][50]. Ammonia is oxidised to nitrite and finally to nitrate through the process of nitrification, with ammonia and nitrite being the most toxic of these metabolites to fish.…”