Rewetting Decreases Carbon Emissions from the Zoige Alpine Peatland on the Tibetan Plateau

Abstract

Abstract:Peatlands play an important role in the global carbon cycle and potentially have a significant impact on regional climate change. Restoring and rewetting the degraded peatlands is an urgent task. However, effects of rewetting on the carbon emissions of peatlands remain poorly understood. In this study, the process of rewetting a piece of the degraded Zoige alpine peatland was experimentally simulated and the derived results were compared with those of natural rewetting by monitoring CO 2 and CH 4 fluxes and other environmental factors before and after rewetting. The natural rewetting results showed that rewetting decreased ecosystem respiration (ER) by about 60%. Furthermore, rewetting increased CH 4 emissions by 127%, decreased total carbon emissions (TCE) from 270 to 157 mg CO 2 m −2 h −1 , and decreased TCE from the entire ecosystem by 42%. The results of the controlled experiment showed that ER decreased gradually as the degree of rewetting was increased, and CH 4 fluxes and changes in water level were significantly and positively correlated: CH 4 fluxes increased from 0.3 (water level −20 cm) to 2.17 mg CH 4 m −2 h −1 (water level 20 cm). After rewetting, the TCE of the whole ecosystem were significantly decreased. Regional observations showed that CO 2 fluxes were significantly and negatively correlated to the water level; and the corresponding CO 2 equivalent was significantly and positively correlated to the water level, while TCE were significantly and negatively correlated to the water level. Our findings indicate that rewetting can decrease carbon emissions and thus contribute in mitigating the adverse effects of climate change in alpine peatland.

Reduced Carbon Dioxide Sink and Methane Source under Extreme Drought Condition in an Alpine Peatland

“…The peatland ecosystem is an essential component of the global terrestrial carbon pool. This ecosystem stores 15-30% of the global soil carbon pool at a proportion of only 3% of the total land area, which plays a vital role in regulating global climate change [14][15][16][17]. The carbon budget in the peatland ecosystem is greatly affected by meteorological factors (temperature, precipitation, light, etc.…”

Catchment-Scale Analysis Reveals High Cost-Effectiveness of Wetland Buffer Zones as a Remedy to Non-Point Nutrient Pollution in North-Eastern Poland

“…Rewetting these soils may not only reduce greenhouse gas emissions, but also create a favourable environment for return of the C sink function, which is characteristic of well-functioning organic soils [62,63]. Rewetting increases CH 4 emissions [64], which shortly after rewetting tend to rise. However, a meta-analysis of available data shows that CH 4 emissions from rewetted peatlands do not differ significantly from undrained ones [65] and are order of magnitude smaller (in CO 2 equivalents) than CO 2 emissions from drained peat.…”

Carbon Balance of Grasslands on the Qinghai-Tibet Plateau under Future Climate Change: A Review

“…Moreover, studies on vegetation with different degrees of degradation (healthy vegetation, mild degradation, moderate degradation, and severe degradation) also showed that ecosystem respiration was mainly affected by temperature, while CH 4 variation was mainly determined by water content [74]. Nevertheless, experiments on moisture restoration in degraded peatlands showed that while increased water content led to increased CH 4 emissions, CO 2 emissions were reduced, resulting in a total carbon emission reduction of more than 40% [67], resulting in a carbon sink trend in the plateau. Therefore, the future carbon balance of the QTP grassland may depend on the influence of water on CO 2 and CH 4 under certain conditions.…”

“…Studies have shown that lower water levels reduce the amount of organic carbon stored in peatlands. It is possible that lowering the water level will increase the activity of aerobic microorganisms [67] and affect the physical and chemical properties of peat, which may lead to soil carbon loss and reduce the content of soil organic carbon [123]. For example, the peatland water level caused by human activities has dropped and earthworms are more active in low-water peatlands than in high-water peatlands such that their activities may change the vegetation biomass, soil structure, and temperature, and may promote the aggregation of other invertebrates, thus accelerating soil organic carbon emissions and indirectly reducing soil organic carbon content [124,125].…”