The decomposition of litter plays an important role in carbon fixation and nutrient utilization in peatland. Warming and nitrogen addition may directly or indirectly affect the carbon sink function of peatland by affecting litter decomposition. However, the effect of temperature increase and nitrogen addition on the litter decomposition in permafrost regions remains unclear, especially from the perspective of CO2 release and microorganisms.
The researchers from the Northeast Institute of Geography and Agroecology of Chinese Academy of Sciences collected the litter of two typical plants, Eriophorum vaginatum and Sphagnum palustre, in the permafrost peatland of the Great Hing'an Mountain and incubated at 10 and 20°C for 54 days. Three nitrogen addition treatments (CK: 0 mg N g-1 , N1: 2.5 mg N g-1 , and N2: 5 mg N g-1) were established. The researchers revealed that the decomposition of E. vaginatum litter is faster than that of Sphagnum, and an increase in temperature significantly promoted the litter decomposition and CO2 emission of E. vaginatum and Sphagnum. Nitrogen addition promoted the decomposition of E. vaginatum litter, whereas the decomposition of Sphagnum litter was promoted by the N1 treatment but was inhibited by the N2 treatment. The enzyme activity in both types of litter was inhibited with the increase in temperature. The abundances of bacteria and fungi positively correlated with the decomposition constant and mean CO2 release rate by E. vaginatum and Sphagnum litter, indicating that the effects of temperature and nitrogen addition on the decomposition of plant litter were primarily regulated by microorganisms. Results of this study clearly reveal the different response of decomposition of the E. vaginatum and Sphagnum litter to temperature increase and nitrogen addition, which can help to assess the effects of addition of nitrogen on carbon and nutrient dynamics during the vegetation succession from mosses to vascular plants in permafrost peatlands under climate change.
The study by GAO Siqi and SONG Yanyu et al. entitled “Effects of temperature increase and nitrogen addition on the early litter decomposition in permafrost peatlands” has been published online in Catena.
This research was funded by the National Natural Science Foundation of China.
SONG Yanyu
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences
http://english.iga.cas.cn/
E-mail: songyanyu@iga.ac.cn
Keywords: Boreal peatland, Eriophorum vaginatum, Sphagnum palustre, Litter decomposition, Enzyme activity
Siqi Gao, Yanyu Song*, Changchun Song, Xianwei Wang, Xiuyan Ma, Jinli Gao, Xiaofeng Cheng, Yu Du. Effects of temperature increase and nitrogen addition on the early litter decomposition in permafrost peatlands. Catena, 2021, 209, 105801.
https://doi.org/10.1016/j.catena.2021.105801
