Flooding duration affects the temperature sensitivity of soil extracellular enzyme activities in a lakeshore wetland in Poyang Lake, China

• Published in: The Science of the total environment 2023-05, Vol.874, p.162397-162397, Article 162397
• Main Authors: Huang, Xingyun, Wang, Kexin, Wen, Xiuting, Liu, Jie, Zhang, Yan, Rong, Jun, Nie, Ming, Fu, Chun, Zheng, Bofu, Yuan, Zhifen, Gong, Leiqiang, Zhan, Huiying, Shen, Ruichang
• Format: Article
• Language: English
• Subjects: Biogeochemical cycle; Carbon - analysis; China; Clay; Ecosystem; Hydrological regimes; Lakes; Lakeshore wetland; Nitrogen - analysis; Phosphorus - chemistry; Soil - chemistry; Soil enzymes; Soil Microbiology; Temperature; Temperature sensitivity; Wetlands
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.162397

Extracellular enzymes play central roles in the biogeochemical cycles in wetland ecosystems. Their activities are strongly impacted by hydrothermal conditions. Under the ongoing global change, many studies reported the individual effects of flooding and warming on extracellular enzyme activities, however, few researches investigated their interactive effects. Therefore, the current study aims to determine the responses of extracellular enzyme activities to warming in wetland soils under divergent flooding regimes. We investigated the temperature sensitivity of seven extracellular enzymes related to carbon (α-glucosidase, AG; β-glucosidase, BG; cellobiohydrolase, CBH; β-xylosidase, XYL), nitrogen (β-N-acetyl -glucosaminidase, NAG; leucine aminopeptidase, LAP), and phosphorus (Phosphatase, PHOS) cycling along the flooding duration gradient in a lakeshore wetland of Poyang Lake, China. The Q10 value, calculated using a temperature gradient (10, 15, 20, 25, and 30 °C), was adopted to represent the temperature sensitivity. The average Q10 values of AG, BG, CBH, XYL, NAG, LAP, and PHOS in the lakeshore wetland were 2.75 ± 0.76, 2.91 ± 0.69, 3.34 ± 0.75, 3.01 ± 0.69, 3.02 ± 1.11, 2.21 ± 0.39, and 3.33 ± 0.72, respectively. The Q10 values of all the seven soil extracellular enzymes significantly and positively correlated with flooding duration. The Q10 values of NAG, AG and BG were more sensitive to the changes in flooding duration than other enzymes. The Q10 values of the carbon, nitrogen, and phosphorus-related enzymes were mainly determined by flooding duration, pH, clay, and substrate quality. Flooding duration was the most dominant driver for the Q10 of BG, XYL, NAG, LAP, and PHOS. In contrast, the Q10 values of AG and CBH were primarily affected by pH and clay content, respectively. This study indicated that flooding regime was a key factor regulating soil biogeochemical processes of wetland ecosystems under global warming. [Display omitted] •The effects of flooding duration (FD) on the Q10 of seven soil EEAs was identified.•With the increasing of FD, the Q10 of soil EEAs all raised in SF wetland.•Q10 of soil EEAs in SF wetland was higher than climate‑carbon model predictions.•The Q10 of NAG, AG, and BG were more sensitive to FD than the Q10 of other enzymes.