Supporting Information legends

Table S1 The geographic location, morphology, watershed land use, sediment denitrification and N2O production of the 20 plateau lakes in southwestern China.

Table S2 Correlations between human land uses in watersheds and lake water chemistry and sediment properties at the lake level (N= 20).

Fig. S1 Potential denitrification, unamended denitrification and N2O production rates (mean±SE) for littoral and profundal sites. Asterisk indicates significant difference at P<0.05.

Fig. S2 Relationships between denitrification and N2O production rates and water chemistry and sediment properties at the site level (N= 68).

Table S1 The geographic location, morphology, watershed land use, sediment denitrification and N2O production of the 20 plateau lakes in southwestern China.

Geographic location / Lake morphology / Watershed land use / Denitrification and N2O production
Lake / Type / Sampling
sites / Longitude / Latitude / Elevation / Mean depth / Surface Area / Water residence time / Cropland / Built-up land / Vegetation / Water body / PD / UD / NP
(°E) / (°N) / (m) / (m) / (km2) / (months) / (%) / (%) / (%) / (%) / (ng N g-1 h-1)
1. Dianchi / H / 6 / 102.61 / 24.76 / 1873 / 2.93 / 297.90 / 11.69 / 26.53 / 8.98 / 51.13 / 13.36 / 12.46 / 0.03 / -0.03
2. Erhai / R / 5 / 100.12 / 25.89 / 1965 / 10.17 / 249.00 / 22.04 / 22.00 / 2.33 / 67.66 / 7.32 / 23.26 / 0.09 / -0.02
3. Fuxianhu / R / 5 / 102.84 / 24.56 / 1729 / 89.60 / 211.00 / 450.89 / 25.92 / 2.16 / 41.1 / 30.82 / 27.00 / 1.07 / 0.01
4. Luguhu / R / 4 / 100.77 / 27.68 / 2452 / 40.30 / 48.45 / 213.05 / 15.88 / 0.49 / 62.57 / 21.06 / 7.70 / 0.02 / -0.05
5. Chenghai / R / 3 / 100.64 / 26.50 / 1513 / 25.70 / 77.22 / 150.15 / 18.32 / 0.23 / 72.93 / 8.52 / 12.35 / 0.23 / 0.03
6. Yilonghu / R / 3 / 102.51 / 23.69 / 1420 / 2.40 / 38.00 / 18.23 / 19.42 / 2.26 / 70.6 / 7.72 / 34.42 / 3.32 / 0.09
7. Qiluhu / H / 3 / 102.77 / 24.16 / 1793 / 4.03 / 36.86 / 12.47 / 42.33 / 5.75 / 42.94 / 8.98 / 99.71 / 8.13 / 0.40
8. Xingyunhu / H / 3 / 102.78 / 24.34 / 1724 / 5.30 / 34.71 / 8.76 / 33.16 / 3.32 / 51.4 / 12.12 / 27.55 / 3.35 / 0.04
9. Yangzonghai / R / 3 / 103.02 / 24.94 / 1765 / 19.50 / 31.68 / 76.33 / 26.19 / 2.67 / 59.04 / 12.1 / 5.40 / 0.77 / 0.06
10. Qionghai / H / 3 / 102.27 / 27.84 / 1508 / 10.32 / 31.00 / 21.10 / 32.42 / 2.87 / 60.42 / 4.29 / 55.07 / 0.41 / 0.05
11. Caohai / H / 3 / 104.26 / 26.85 / 2172 / 2.40 / 25.00 / 10.00 / 31.08 / 1.67 / 56.07 / 11.17 / 42.78 / 0.27 / 0.03
12. Datunhai / H / 3 / 103.30 / 23.41 / 1290 / 3.70 / 12.33 / 14.30 / 34.32 / 6.09 / 51.26 / 8.32 / 34.75 / 0.92 / 0.14
13. Changqiaohai / H / 3 / 103.37 / 23.39 / 1283 / 3.74 / 10.70 / 8.74 / 44.80 / 4.70 / 42.8 / 7.7 / 22.67 / 0.22 / 0.08
14. Lashihai / H / 3 / 100.14 / 26.86 / 2444 / 1.50 / 9.33 / No data / 27.65 / 3.63 / 64.31 / 4.41 / 14.68 / 0.23 / 0.05
15. Cibihu / R / 3 / 99.94 / 26.15 / 2051 / 11.00 / 8.46 / No data / 21.46 / 4.58 / 66.69 / 7.27 / 21.66 / 0.22 / 0.05
16. Jianhu / R / 3 / 99.94 / 26.49 / 2187 / 4.50 / 5.70 / No data / 21.17 / 1.20 / 76.5 / 0.81 / 25.58 / 0.43 / 0.01
17. Nanhu / H / 3 / 103.39 / 23.36 / 1308 / 1.50 / 5.00 / No data / 62.58 / 25.91 / 6.64 / 4.87 / 31.76 / 0.90 / -0.01
18. Jinhu / R / 3 / 103.16 / 23.37 / 1681 / 2.00 / 3.00 / No data / 11.66 / 10.81 / 75.89 / 1.64 / 11.45 / 0.32 / 0.08
19. Xihu / R / 3 / 100.05 / 26.01 / 1971 / 1.80 / 2.10 / No data / 25.71 / 3.49 / 66.37 / 4.43 / 30.69 / 0.20 / 0.08
20. Changhu / R / 3 / 103.41 / 24.71 / 1885 / 24.00 / 0.54 / No data / 8.82 / 1.06 / 88.96 / 1.16 / 3.97 / 0.15 / -0.01

H: Human-dominated lakes; R: Reference lakes.

PD: Potential denitrification; UD: Unamended denitrification; NP: N2O production.

Table S2 Correlations between human land uses in watersheds and lake water chemistry and sediment properties at the lake level (N= 20).

Percentage of human land uses / Area of human land uses / Area of human land uses: lake area
Water chemistry
Temperature / 0.310 / -0.050 / 0.410
pH / 0.218 / 0.063 / 0.091
Depth / 0.013 / 0.283 / -0.232
Secchi depth / -0.293 / 0.142 / 0.200
Dissolved oxygen / 0.122 / -0.205 / 0.360
Conductivity / 0.265 / 0.104 / -0.128
Total nitrogen / 0.537* / -0.038 / 0.055
Total dissolved nitrogen / 0.613** / 0.068 / 0.091
Sediment properties
pH / 0.123 / 0.139 / 0.109
Bulk density / 0.201 / 0.444* / 0.163
Moisture / 0.336 / 0.096 / 0.152
Sediment organic matter / 0.289 / -0.051 / 0.560*
Sediment total carbon / 0.011 / 0.179 / 0.370
Sediment total nitrogen / -0.049 / 0.299 / 0.446*

* Significant at the 0.05 level

** Significant at the 0.01 level

Fig. S1

Fig. S2