Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6536873 | Agricultural and Forest Meteorology | 2018 | 18 Pages |
Abstract
Net ecosystem exchange of carbon dioxide (NEE) and its components, gross primary productivity (GPP) and ecosystem respiration (ER), were compared between a bog and an abandoned peatland pasture within the same peatland complex in western Newfoundland, Canada. Measurements based on the eddy covariance technique from April 2014 to April 2016 were used to examine the influence of agricultural management and abandonment on peatland carbon dioxide (CO2) exchange. NEE, GPP and ER at both sites showed pronounced seasonal variation, peaking near the middle growing season. The maximum net CO2 uptake rate of â28.61 μmol mâ2 sâ1 and emission rate of 14.39 μmol mâ2 sâ1 at the pasture were significantly higher than those at the bog (â9.67 μmol mâ2 sâ1 and 5.50 μmol mâ2 sâ1, respectively). Daytime average GPP was related to photosynthetic photon flux density and air temperature and the nighttime average ER decreased with soil water content, but increased with surface soil temperature for both sites. Annual NEE of the pasture (â128 ± 60 g C mâ2 yrâ1 in 2014-15 and â124 ± 56 g C mâ2 yrâ1 in 2015-16) was considerably larger than that of the bog (â46 ± 36 g C mâ2 yrâ1 in 2014-15). GPP of 1086 ± 141 g C mâ2 yrâ1 in 2014-15 and 982 ± 123 g C mâ2 yrâ1 in 2015-16 and ER of 957 ± 129 g C mâ2 yrâ1 in 2014-15 and 858 ± 112 g C mâ2 yrâ1 in 2015-16 at the pasture were approximately twice the magnitude of the corresponding fluxes at the bog. The difference in GPP between the bog and pasture was mainly related to their different aboveground biomass. Higher ER at the pasture was probably related to its lower water table depth, greater substrate availability and higher autotrophic respiration. Unlike previous findings that managed peatlands are large CO2 emitters, our results suggest that abandoned peatland pastures can function like natural grasslands and sequester considerable amounts of CO2 from the atmosphere.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Atmospheric Science
Authors
Mei Wang, Jianghua Wu, Peter M. Lafleur, Junwei Luan, Huai Chen, Xinbiao Zhu,