Effect of Water Level Fluctuation and Nitrate Concentration on Soil-Surface CO2 and CH4 Emissions from Riparian Freshwater Marsh Wetland

Autor: Yunlong Yao, Shan Yuanqi, Hongxian Yu, Patteson Chula Mwagona
Rok vydání: 2021
Předmět:
Zdroj: Wetlands. 41
ISSN: 1943-6246
0277-5212
Popis: This study assessed the effect of water level fluctuation and $${\mathrm{NO}}_3^{-}$$ concentration levels on the soil CO2 and CH4fluxes from wetland. Intact soil columns collected from sites dominated by different vegetation types were incubated in laboratory and continuously treated with $${\mathrm{NO}}_3^{-}$$ enriched water. CO2 and CH4fluxes were measured from three manipulated water levels: 5 cm above the soil water surface, −10 cm and -20 cm below the soil water surface. Two $${\mathrm{NO}}_3^{-}$$ concentration levels 30 mg/L and 60 mg/L were used. This study revealed significant interaction effect between $${\mathrm{NO}}_3^{-}$$ concentration and water level on CO2 and CH4 fluxes. Water level fluctuation significantly affected CO2 fluxes. The overall mean CO2 emission at 5 cm of 6.45 mg/m2/h was two and five times lower than that at −10 cm (22.52 mg/m2/h) and − 20 cm (32.50 mg/m2/h), respectively. The mean CO2 fluxes in Calamagrostis angustifolia Kom was significantly higher when high $${\mathrm{NO}}_3^{-}$$ concentration was added in the soil while in Phragmites australis (Cav.) Trin. ex Steud and Carex pseudocuraica F.Schmidt higher CO2 fluxes were observed when low $${\mathrm{NO}}_3^{-}$$ concentration was added. $${\mathrm{NO}}_3^{-}$$ concentration levels significantly affected CH4 fluxes with the highest mean values measured when low $${\mathrm{NO}}_3^{-}$$ concentration was added. This implies that there could be significant change in CO2 and CH4 fluxes as a response of water level drawdown due to wetland drainage. High $${\mathrm{NO}}_3^{-}$$ concentration leads to increase in CO2 in C. pseudo-curaica likely due to nutritional effect, and reduction in CO2 in C. pseudo-curaica and P. australis probable due to inducing carbon-limitation.
Databáze: OpenAIRE
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