Fluctuations of Water Table Level in a Subtropical Peatland, Central China

Water level is the overriding control on carbon cycles in peatlands, which are important for global carbon cycles and ecosystem services. To date, our knowledge of the pattern of water level fluctuations in peatlands and the influence of precipitation and air temperature on them in the subtropical remains poor. In this study, we conducted continuous high-resolution monitoring of water levels from 2014 to 2021 in the Dajiuhu peatland, a typically subtropical peatland in central China. Monitoring results showed that the water level had strong annual (370 days) and seasonal (130 days) oscillations in the Dajiuhu peatland. The annual oscillation is associated with both precipitation and temperature, while the seasonal oscillation is mainly controlled by precipitation. In addition, the depth of peat surface to the water table (DWT) has weak but significant correlations with precipitation and temperature on the daily and weekly scales (r = 0.1–0.21, p < 0.01). Once replacing DWT with water table fluctuation cumulation, the correlation coefficients increase apparently (r = 0.47–0.69, p < 0.01), especially on the monthly scale. These findings highlight a more important role of the fluctuation than the mean position of water level and have the potential to improve the interpretation of water-level related paleoenvironmental proxies and the understanding of the relationship between water level and biogeochemical processes.