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Effects of Warming on CO2 Fluxes in an Alpine Meadow Ecosystem on the Central Qinghai-Tibetan Plateau.

Ganjurjav H, Gao Q, Zhang W, Liang Y, Li Y, Cao X, Wan Y, Li Y, Danjiu L - PLoS ONE (2015)

Bottom Line: The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under warming in the alpine meadow.The seasonal dynamic patterns of GEP and NEE, but not ER, were significantly impacted by warming.The effect of warming on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to warming, require further researched.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China; Key Laboratory for Agro-Environment & Climate Change, Ministry of Agriculture, Beijing, China.

ABSTRACT
To analyze CO2 fluxes under conditions of climate change in an alpine meadow on the central Qinghai-Tibetan Plateau, we simulated the effect of warming using open top chambers (OTCs) from 2012 to 2014. The OTCs increased soil temperature by 1.62°C (P < 0.05), but decreased soil moisture (1.38%, P < 0.05) during the experiments. The response of ecosystem CO2 fluxes to warming was variable, and dependent on the year. Under conditions of warming, mean gross ecosystem productivity (GEP) during the growing season increased significantly in 2012 and 2014 (P < 0.05); however, ecosystem respiration (ER) increased substantially only in 2012 (P < 0.05). The net ecosystem CO2 exchange (NEE) increased marginally in 2012 (P = 0.056), did not change in 2013(P > 0.05), and increased significantly in 2014 (P = 0.034) under conditions of warming. The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under warming in the alpine meadow. Under warming, the 3-year averages of GEP, ER, and NEE increased by 19.6%, 15.1%, and 21.1%, respectively. The seasonal dynamic patterns of GEP and NEE, but not ER, were significantly impacted by warming. Aboveground biomass, particularly the graminoid biomass increased significantly under conditions of warming. Soil moisture, soil temperature, and aboveground biomass were the main factors that affected the variation of the ecosystem CO2 fluxes. The effect of warming on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to warming, require further researched.

No MeSH data available.


Related in: MedlinePlus

The relationships between ecosystem CO2 fluxes: gross ecosystem productivity (GEP) (filled cycles and solid lines), ecosystem respiration (ER) (filled triangles and dashed lines), and net ecosystem CO2 exchange (NEE) (open cycles and dotted lines), and aboveground biomass: total biomass, graminoid biomass, forb biomass, and biomass ratio of graminiod/forb across 2012 to 2014.
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pone.0132044.g005: The relationships between ecosystem CO2 fluxes: gross ecosystem productivity (GEP) (filled cycles and solid lines), ecosystem respiration (ER) (filled triangles and dashed lines), and net ecosystem CO2 exchange (NEE) (open cycles and dotted lines), and aboveground biomass: total biomass, graminoid biomass, forb biomass, and biomass ratio of graminiod/forb across 2012 to 2014.

Mentions: During the three growing seasons, the temporal variation of GEP, ER, and NEE increased linearly with increasing soil temperature in both the control and warming treatment plots (Table 3). The slope of the regression for GEP—temperature was steeper than ER—temperature in both the control (P = 0.022) and warming plots (P = 0.071). The soil moisture also influenced the temporal variation of GEP and NEE, but not ER, in both the control and treatment plots (Table 3). Stepwise multiple regression analyses showed that soil temperature and soil moisture together accounted for 49.4% (P<0.001) and 42.6% (P = 0.001), respectively, of the temporal variation in GEP in the control and warming treatment plots, and were responsible for 50.9% (P<0.001) and 44.8% (P<0.001), respectively, of the temporal variation in the NEE in the control and warming plots. Moreover, the GEP, ER, and NEE were linearly and positively correlated with the total aboveground biomass (Fig 5a) and graminoid biomass (Fig 5b). The CO2 fluxes were not correlated to forb biomass (Fig 5c) and biomass ratio of graminoid and forb (Fig 5d) in the three growing seasons.


Effects of Warming on CO2 Fluxes in an Alpine Meadow Ecosystem on the Central Qinghai-Tibetan Plateau.

Ganjurjav H, Gao Q, Zhang W, Liang Y, Li Y, Cao X, Wan Y, Li Y, Danjiu L - PLoS ONE (2015)

The relationships between ecosystem CO2 fluxes: gross ecosystem productivity (GEP) (filled cycles and solid lines), ecosystem respiration (ER) (filled triangles and dashed lines), and net ecosystem CO2 exchange (NEE) (open cycles and dotted lines), and aboveground biomass: total biomass, graminoid biomass, forb biomass, and biomass ratio of graminiod/forb across 2012 to 2014.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492951&req=5

pone.0132044.g005: The relationships between ecosystem CO2 fluxes: gross ecosystem productivity (GEP) (filled cycles and solid lines), ecosystem respiration (ER) (filled triangles and dashed lines), and net ecosystem CO2 exchange (NEE) (open cycles and dotted lines), and aboveground biomass: total biomass, graminoid biomass, forb biomass, and biomass ratio of graminiod/forb across 2012 to 2014.
Mentions: During the three growing seasons, the temporal variation of GEP, ER, and NEE increased linearly with increasing soil temperature in both the control and warming treatment plots (Table 3). The slope of the regression for GEP—temperature was steeper than ER—temperature in both the control (P = 0.022) and warming plots (P = 0.071). The soil moisture also influenced the temporal variation of GEP and NEE, but not ER, in both the control and treatment plots (Table 3). Stepwise multiple regression analyses showed that soil temperature and soil moisture together accounted for 49.4% (P<0.001) and 42.6% (P = 0.001), respectively, of the temporal variation in GEP in the control and warming treatment plots, and were responsible for 50.9% (P<0.001) and 44.8% (P<0.001), respectively, of the temporal variation in the NEE in the control and warming plots. Moreover, the GEP, ER, and NEE were linearly and positively correlated with the total aboveground biomass (Fig 5a) and graminoid biomass (Fig 5b). The CO2 fluxes were not correlated to forb biomass (Fig 5c) and biomass ratio of graminoid and forb (Fig 5d) in the three growing seasons.

Bottom Line: The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under warming in the alpine meadow.The seasonal dynamic patterns of GEP and NEE, but not ER, were significantly impacted by warming.The effect of warming on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to warming, require further researched.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China; Key Laboratory for Agro-Environment & Climate Change, Ministry of Agriculture, Beijing, China.

ABSTRACT
To analyze CO2 fluxes under conditions of climate change in an alpine meadow on the central Qinghai-Tibetan Plateau, we simulated the effect of warming using open top chambers (OTCs) from 2012 to 2014. The OTCs increased soil temperature by 1.62°C (P < 0.05), but decreased soil moisture (1.38%, P < 0.05) during the experiments. The response of ecosystem CO2 fluxes to warming was variable, and dependent on the year. Under conditions of warming, mean gross ecosystem productivity (GEP) during the growing season increased significantly in 2012 and 2014 (P < 0.05); however, ecosystem respiration (ER) increased substantially only in 2012 (P < 0.05). The net ecosystem CO2 exchange (NEE) increased marginally in 2012 (P = 0.056), did not change in 2013(P > 0.05), and increased significantly in 2014 (P = 0.034) under conditions of warming. The GEP was more sensitive to climate variations than was the ER, resulting in a large increase in net carbon uptake under warming in the alpine meadow. Under warming, the 3-year averages of GEP, ER, and NEE increased by 19.6%, 15.1%, and 21.1%, respectively. The seasonal dynamic patterns of GEP and NEE, but not ER, were significantly impacted by warming. Aboveground biomass, particularly the graminoid biomass increased significantly under conditions of warming. Soil moisture, soil temperature, and aboveground biomass were the main factors that affected the variation of the ecosystem CO2 fluxes. The effect of warming on inter- and intra-annual patterns of ecosystem CO2 fluxes and the mechanism of different sensitivities in GEP and ER to warming, require further researched.

No MeSH data available.


Related in: MedlinePlus