Yang,C., Wang,S., Jin,X. and Wu,F.(2010): Nitrogen and phosphorus mineralization in sediments of Taihu Lake after the removal of light fraction organic matter. Environ. Earth Sci., 59, 1437-1446.

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wAbstract
@Mineralization of organic matter (OM) in sediments is crucial for biogeochemical cycle of nitrogen (N) and phosphorus (P) in lake ecosystem. Light fraction OM (LFOM is a reactive pool in sediment and is considered as labile fraction contributing to N and P cycling. In our study, the effect of LFOM on the process and characteristics of N and P mineralization in sediments of Taihu Lake were investigated with 77-day waterlogged incubation plus intermittent leaching at 27Ž. Sediments from Yiantouzhu (Y) and Gonghu (G) were used, which were removed the LF. Results indicated that the organic nitrogen mineralized ranged from 14.3 to 19.5“ of total nitrogen (193.49-378.93 mg kg-1 sediment) and the organic phosphorus mineralized ranged from 5.7 to 7.9“ of total phosphorus (19.86-60.65 mg kg-1 sediment). The heavily polluted sediment had a higher mineralization rate and net mineral-N and mineral-P than slightly polluted sediment. LF stimulated the initial amounts of inorganic N and P and also can be the potential source for mineralization. After the LFOM removal, the net mineral-N of Y and G decreased 116.47 mg kg-1 sediment and 48.03 mg kg-1 sediment, respectively, and the net mineral-P decreased 2.67 mg kg-1 sediment for Y and 4.82 mg kg-1 sediment for G. Two models were used to fit the observed mineral-N data vs. incubation days using a non-linear regression procedure: one is the effective cumulated temperature model, a thermodynamic model which assumes that N mineralization is affected by temperature; the other is the single first-order exponential model, which is a dynamic model. Based on root mean square error values for the two models, the effective cumulated temperature model made a better prediction of N mineralization than the other model for all the four treatments. The single first-order exponential model underestimated N mineralization during the first 14 days and the last 21 days, and overestimated it in the other days during the 77-day incubation. This indicated that temperature was the primary factor influencing \n mineralization and the amount of mineral-N were correlated significantly with the effective cumulated temperature (T†15Ž) and incubation time when waterlogged incubation plus intermittent leaching was used.

keywords: Nitrogen; Phosphorus; Mineralization; Model; Sedimentsx

Introduction
Materials and methods
@Sediment sampling
@Light fraction removal
@Anaerobic incubation experiments
@Laboratory analysis
@The models
Results
@Basic sediment properties
@N mineralization
@P mineralization
@Model fitting
Discussion
@Effect of LFOM on mineralization
@Model fitting
Conclusions
Acknowledgments
References


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