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Table 1 Mean values of experimental parameters in the artificial laboratory stream with control (2 × 6) and treatment groups (2 × 6)

From: Short-term effects of elevated CO2 on periphyton community in an artificially constructed channel

Experimental parameters Control Treatment p
Water Temperature (°C) 4.8 ± 0.2 4.8 ± 0.2 0.235
pH 9.18 ± 0.06 9.02 ± 0.03 0.026
Electric conductivity (μS/cm) 267.8 ± 2.7 268.0 ± 2.8 0.611
Chlorophyll-a (μg/L) 85.12 ± 11.42 88.99 ± 11.56 0.332
Suspended solid (mg/L) 23.33 ± 1.22 23.08 ± 3.53 0.932
NO2-N (μg/L) 51.00 ± 0.40 50.00 ± 0.20 0.550
NO3-N (mg/L) 2.60 ± 0.05 2.58 ± 0.05 0.184
NH3-N (μg/L) 10.00 ± 0.20 8.00 ± 0.20 0.042
Total nitrogen (mg/L) 3.45 ± 0.07 3.43 ± 0.06 0.367
PO4-P (μg/L) 1.30 ± 0.90 0.80 ± 0.30 0.258
Total phosphorus (μg/L) 51.00 ± 0.20 49.00 ± 0.30 0.490
Total organic carbon (mg/L) 5.34 ± 0.34 5.68 ± 0.19 0.319
Inorganic carbon (mg/L) 14.66 ± 0.64 13.49 ± 0.64 0.112
Total carbon (mg/L) 20.00 ± 0.65 19.17 ± 0.52 0.253
Substrate Periphyton chlorophyll-a (μg/cm2) 5.28 ± 1.29 6.75 ± 1.35 0.008
Periphyton ash-free dry-matter (mg/cm2) 1.09 ± 0.15 1.29 ± 0.15 0.000
Periphyton density (106 cells/cm2) 4.2 ± 0.7 5.6 ± 0.9 0.003
Fragilaria capucina var. gracilis (106 cells/cm2) 3.2 ± 0.5 4.3 ± 0.7 0.008
Fragilaria capucina (106 cells/cm2) 0.8 ± 0.2 1.0 ± 0.3 0.095
Cryptomonas ovata (104 cells/cm2) 5.9 ± 0.5 7.9 ± 0.8 0.016
Scenedesmus quadricauda (104 cells/cm2) 5.3 ± 0.7 5.0 ± 0.8 0.706
Aulacoseira ambigua (104 cells/cm2) 3.2 ± 0.6 4.2 ± 0.8 0.468
  1. The artificial stream was operated for 10 days in December 2012. The control stream functioned under atmospheric CO2 (395 ppm) and the treatment group functioned under added CO2 (790 ppm)