Nitrogen along the Hydrological Gradient of Marsh Sediments in a Subtropical Estuary: Pools, Processes, and Fluxes
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Site
2.2. Sampling and Analysis
2.3. Slurry Incubations
2.4. Dissolved Inorganic Nitrogen Flux Measurements
2.5. Statistical Analyses
3. Results
3.1. Plant Biomass and Sediment Geochemistry along a Hydrological Gradient
3.2. Distribution of Nitrogen Pools, Processes, and Fluxes
3.3. Structural Equation Modeling Analysis of the Drivers, Causal Links, and Contribution to the Priming Effect
4. Discussion
4.1. Spatial Distribution of Nitrogen Processes
4.2. Spatial Distribution of Nitrogen Pools
4.3. Spatial Distribution of Nitrogen Fluxes
4.4. Implications, Uncertainties, and Future Study
5. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Nitrogen Process | Location | Depth (cm) | Value | Distribution | References | |
---|---|---|---|---|---|---|
N pool | TN (g kg−1) | Yangtze Estuary, China | 0–10, 40–100 | 1.4–7.8 | H > M ≈ L | [18] |
10–40 | H ≈ M > L | |||||
Yangtze Estuary, China | 0–15 | – | H ≥ M ≈ L | [17] | ||
Petersgroden, Cäciliengroden, and Neβmersiel Germany | 0–15 | 2.6–6.8 | H > M > L | [29] | ||
Nordschweiburg and Dangast, Germany | 0–15 | 3.1–4.2 | M > L ≥ H | [29] | ||
Luoyuan Bay, China | 0–40 | 5.4–10.1 | H > M > L | [30] | ||
40–131 | M ≈ L > H | [30] | ||||
NH4+ (mg kg−1) | Tagus Estuary, Portugal | 0–5 | 0.004–4.1 | L > H | [28] | |
Yellow River Delta, China | 0–10 | 1.0–6.5 | H ≈ M ≈ L | [23] | ||
NO3− (mg kg−1) | Tagus Estuary, Portugal | 0–5 | 0.03–2.5 | L > H | [28] | |
Yellow River Delta, China | 0–10 | 0.7–8.4 | H ≥ M ≈ L | [23] | ||
N process | PNR | East coast of Jutland, Denmark | 0–8 | – | H > L | [25] |
PNmin (mg kg−1 d−1) | Yellow River Delta, China | 0–10 | −0.23–0.24 | L ≥ M ≥ H | [23] | |
PDNR (μmol N m−2 h−1) | Colne Estuary, UK | 0–10 | 1.1–98.2 | H ≈ L | [27] | |
Mid-Atlantic Bight, North Atlantic Ocean | 0–8 | 0.006–0.2 | W17m > W15m ≈ W11m | [32] | ||
Randers Fjord and Norsminde Fjord, Denmark | 0–0.5 | – | W1m > W0.5m | [33] | ||
Colne Estuary and Humber Estuary, UK | 0–2 | 0.1–421.7 | H > M > L | [38] | ||
Conwy Estuary, UK | 0–2 | 0–108 | M > H > L | [38] | ||
Weeks Bay Estuarine, USA | 0–19 | 21.6–33.6 | M ≈ L | [26] | ||
Inorganic N fluxes at the sediment–water interface. | Flux of NO3− (mmol m−2 h−1) | Tagus Estuary, Portugal | – | −0.8–1.8 | H (–), L (+) | [28] |
Mid-Atlantic Bight, North Atlantic Ocean | – | −0.01–0.02 | W11m (±), W15m (±), W17m (–) | [32] | ||
Randers Fjord and Norsminde Fjord, Denmark | – | −120.0–47.0 | W1m (–) > W0.5m (–) | [33] | ||
Yangtze Estuary, China | – | −0.8–0.4 | H (±), I (±), M (±) | [11] | ||
Flux of NH4+ (mmol m−2 h−1) | Tagus Estuary, Portugal | – | 0.02–0.09 | H (+), L (+) | [28] | |
Mid-Atlantic Bight, North Atlantic Ocean | – | −0.02–0.12 | W11m (±), W15m (+), W17m (+) | [32] | ||
Yangtze Estuary, China | −0.2–0.6 | H (±), I (±), M (±) | [11] |
Depth (cm) | Sites | BD (g cm−3) | pH (1:5, Soil:H2O) | EC (mS cm−1) | TC (mg g−1) | Grain Size (%) | ||
---|---|---|---|---|---|---|---|---|
Clay | Silt | Sand | ||||||
0–10 | Site A | 0.71 ab | 5.88 c | 3.58 a | 39.36 a | 26.94 a | 68.54 a | 4.53 a |
Site B | 0.75 a | 6.45 b | 3.35 a | 24.56 b | 29.51 a | 69.59 a | 0.90 b | |
Site C | 0.63 b | 7.32 a | 3.29 a | 15.70 c | 20.40 a | 75.28 a | 4.32 a | |
10–20 | Site A | 0.89 a | 6.24 a | 2.48 a | 27.89 a | 34.51 a | 63.61 b | 1.88 a |
Site B | 0.70 b | 6.50 a | 3.08 a | 21.34 b | 31.52 ab | 66.73 ab | 1.75 a | |
Site C | 0.75 ab | 7.17 a | 3.04 a | 15.37 c | 26.08 b | 71.12 a | 2.81 a | |
20–30 | Site A | 0.95 b | 6.60 ab | 2.13 b | 18.49 b | 34.98 a | 63.55 b | 1.46 a |
Site B | 0.81 a | 6.41 b | 2.96 a | 22.56 a | 34.54 ab | 64.18 ab | 1.28 a | |
Site C | 0.85 ab | 7.46 a | 2.07 b | 15.01 c | 26.66 b | 70.59 a | 2.76 a | |
30–40 | Site A | 1.01 a | 6.81 b | 1.89 b | 17.74 b | 30.98 a | 65.99 b | 3.04 a |
Site B | 0.73 b | 6.44 b | 2.65 a | 20.81 a | 32.14 ab | 66.48 ab | 1.38 a | |
Site C | 0.84 ab | 7.66 a | 1.90 b | 14.69 c | 26.96 b | 70.52 a | 2.52 a | |
40–50 | Site A | 1.03 a | 6.58 b | 2.00 b | 16.29 b | 25.92 a | 67.01 b | 7.08 a |
Site B | 0.80 b | 6.65 b | 2.54 a | 20.93 a | 27.39 a | 69.88 ab | 2.73 a | |
Site C | 0.82 b | 7.66 a | 2.00 b | 14.58 b | 23.95 a | 72.93 a | 3.12 a |
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Hu, W.; Zhang, W.; Zhang, L.; Tong, C.; Sun, Z.; Chen, Y.; Zeng, C. Nitrogen along the Hydrological Gradient of Marsh Sediments in a Subtropical Estuary: Pools, Processes, and Fluxes. Int. J. Environ. Res. Public Health 2019, 16, 2043. https://doi.org/10.3390/ijerph16112043
Hu W, Zhang W, Zhang L, Tong C, Sun Z, Chen Y, Zeng C. Nitrogen along the Hydrological Gradient of Marsh Sediments in a Subtropical Estuary: Pools, Processes, and Fluxes. International Journal of Environmental Research and Public Health. 2019; 16(11):2043. https://doi.org/10.3390/ijerph16112043
Chicago/Turabian StyleHu, Weifang, Wenlong Zhang, Linhai Zhang, Chuan Tong, Zhigao Sun, Yuehmin Chen, and Congsheng Zeng. 2019. "Nitrogen along the Hydrological Gradient of Marsh Sediments in a Subtropical Estuary: Pools, Processes, and Fluxes" International Journal of Environmental Research and Public Health 16, no. 11: 2043. https://doi.org/10.3390/ijerph16112043