Influencing factors of methane emission dynamics at different water depths in hangzhou bay reed wetland, China

Abstract

Water depth (WD) influences wetland methane (CH 4 ) emissions by affecting plant growth and the physical and chemical properties of soil. We studied the factors influencing CH 4 emission dynamics at different WD in reclaimed reed wetland in Hangzhou Bay, China. The annual average WD was set as WD0 (0 cm), WD1 (10 cm), WD2 (20 cm), and WD3 (35 cm). The transparent chamber-gas chromatography method was used to determine CH 4 fluxes during the growing season. Results showed that the average CH 4 flux was 7.03 mg m 22 h 21 , and that CH 4 fluxes under all 4 WDs presented as a CH 4 source. CH 4 emissions of the reed wetland showed obvious seasonal changes; summer was the peak period for CH 4 emissions. In a vigorous growth period of reeds, the CH 4 flux gradually increased as WD increased. However, in early and late growth periods of reed, CH 4 flux first increased (WD0 < WD1 < WD2) then decreased (WD2 > WD3) as WD increased. Correlation analysis showed that at the 4 WDs, CH 4 flux was significantly, positively correlated with air temperature, soil temperature, and aboveground biomass of reeds, and were highly significantly positively correlated with water temperature. In addition, at WD0, CH 4 flux also showed a significant, positive correlation with soil organic carbon content in the 0-5 and 5-10 cm soil layers, and was significantly negatively correlated with soil water content. Hence, WD significantly influenced wetland CH 4 emissions. Temperature and biomass were major influencing factors of CH 4 emission in reed wetland at different WDs.

Methane production potential and emission at different water levels in the restored reed wetland of Hangzhou Bay

“…Five samples were obtained at 10-min intervals during 40-min sampling periods after the chamber was sealed. Detailed structure of the chamber and specific sampling procedures were described by Shao et al (2017)[ 31 ]. A total of 100 ml of sample gas was drawn into the syringe.…”

Effects of Lotus (Nelumbo nucifera Gaertn.) on the Methane Emission in Littoral Zones of a Subtropical Lake, China

“…SPSS v 18.0 software was used for data processing and statistical analyses [30]. The independent-samples t-test was used to determine the statistical significance of differences in mean CH 4 emission, SOC content, TN, TP, plant biomass, and soil pH.…”

“…Three soil samples were also collected at a depth of 10 cm; subsequently, the soil samples were transferred to the laboratory and dried at 70 • C for 48 h. All soil samples were milled and passed through a 0.149 mm sieve, and soil samples of 100-500 mg were weighed to determine the soil organic carbon (SOC) content using the potassium dichromate oxidation external heating method. A soil sample of 10 g was weighed for pH measurements; the water-to-soil ratio was 2.5 to 1, and the pH value of the soil was measured using the potentiometric method [30]. Soil samples of 1000 mg were weighed to measure the total nitrogen (TN) content by using the Kjeldahl method with H 2 SO 4 digestion, and soil samples of 200 mg were weighed to determine the total phosphorus (TP) content of the soil samples using the colorimetry by alkali fusion with NaOH [28].…”

Plant biomass and soil organic carbon are main factors influencing dry-season ecosystem carbon rates in the coastal zone of the Yellow River Delta

“…However, other studies have considered DOC, SOC, and pH as the related factors to predict CH 4 flux in coastal wetlands [15,16]. Furthermore, the soil water level has also been considered as the main driving factor of regulating CO 2 and CH 4 fluxes in estuary and other coastal wetlands [18,19,21,22]. However, the underlying mechanism of regulating ecosystem C fluxes remains unclear.…”