『Abstract
Excessive nutrient loading and changing hydrological regimes
can significantly impact the ecological function of wetland ecosystems.
Three wetland sediment samples collected from West Lake, Xiazhuhu
Wetland and Baoyang River in the Taihu Lake Watershed, China,
were compared to understand the P retention properties responding
to hydrological regimes by using static column and steady-flow
flume laboratory-scale experiments. Sediment in Xiazhuhu Wetland
currently function as a P sink with equilibrium P concentration
(EPC0) values of 0.010 mg L-1,
while sediments from West Lake and Baoyang River, have EPC0 values of 0.050 mg L-1 and 0.023
mg L-1, respectively, and serve as an internal P source.
The P retention by sediments ranged from 17.20 to 22.61 mg m-2
d-1 under 35-d static conditions, while sediment beds
continuously fed by the simulated inflow water containing 2 mg
L-1 P ranged from 59.20 to 171.93 mg m-2
d-1. The P removal capacities by sediments were higher
during the rainy season than the dry season when wetlands were
subjected to excessive P input. Since the majority of external
P stored in sediment is in the form of Al-P (e.g., for Xiazhuhu
wetland), the application of alum to water column could potentially
increase the P retention capacity of sediment.
Keywords: Equilibrium phosphorus concentration; Phosphorus flux;
Static column; Steady-flow flume; Sediment』
1. Introduction
2. Materials and methods
2.1. Sediment sampling
2.2. Physicochemical analysis and sediment
2.3. Physicochemical analysis of water
2.4. Laboratory-scale experiments
2.5. Mean P flux calculation
3. Results and discussion
3.1. P adsorption properties
3.2. DRP dynamics during the laboratory-scale incubation
3.3. Mean P retention of sediments
3.4. Change of P forms
4. Conclusion
Acknowledgements
References