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. 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 (T15) and incubation time when waterlogged
incubation plus intermittent leaching was used.
keywords: Nitrogen; Phosphorus; Mineralization; Model; Sedimentsx
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