Responses of Phenol Oxidase Activity to Water Level Changes in Peatlands: Implications for Global Carbon Cycling

摘要

Phenol oxidase is expected to play a “latch” role in the responses of carbon cycling in peatlands to global climate change. The effects of water level changes on phenol oxidase activity and phenolic substances were examined in two typical peatlands, bog and swamp, located in Hsiao Hsinganling, Heilongjiang province, north China. The results indicted the ratio of measured phenol oxidase activity to phenolics concentration is an effective index mark illustrating the impacts of water level changes on phenol oxidase involved carbon cycling processes. The responses of phenol oxidase activities to water level changes are subject to not only oxygen restrictions but also acidification/drought stress. For swamp, biogeochemical processes at upmost surface (0-10 cm) act as a pivotal role in responses of carbon cycling to water level changes. Nevertheless, biogeochemical responses in deeper bog peat (10-18 cm) to water level depression can not be neglected in assessing the impacts of moisture condition changes on enzyme-involved soil organic matter decomposition.