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Belowground carbon responses to experimental warming regulated by soil moisture change in an alpine ecosystem of the Qinghai-Tibet Plateau.

Xue X, Peng F, You Q, Xu M, Dong S - Ecol Evol (2015)

Bottom Line: Our results show that 3 years of warming treatments significantly elevated soil temperature at 0-100 cm depth, decreased soil moisture at 10 cm depth, and increased soil moisture at 40-100 cm depth.In contrast to the findings of previous research, experimental warming did not significantly affect NH 4 (+)-N, NO 3 (-)-N, and heterotrophic respiration, but stimulated the growth of plants and significantly increased root biomass at 30-50 cm depth.Analysis shows that experimental warming influenced deeper root production via redistributed soil moisture, which favors the accumulation of belowground carbon, but did not significantly affected the decomposition of soil organic carbon.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 320 West Donggang Road Lanzhou 730000 China.

ABSTRACT
Recent studies found that the largest uncertainties in the response of the terrestrial carbon cycle to climate change might come from changes in soil moisture under the elevation of temperature. Warming-induced change in soil moisture and its level of influence on terrestrial ecosystems are mostly determined by climate, soil, and vegetation type and their sensitivity to temperature and moisture. Here, we present the results from a warming experiment of an alpine ecosystem conducted in the permafrost region of the Qinghai-Tibet Plateau using infrared heaters. Our results show that 3 years of warming treatments significantly elevated soil temperature at 0-100 cm depth, decreased soil moisture at 10 cm depth, and increased soil moisture at 40-100 cm depth. In contrast to the findings of previous research, experimental warming did not significantly affect NH 4 (+)-N, NO 3 (-)-N, and heterotrophic respiration, but stimulated the growth of plants and significantly increased root biomass at 30-50 cm depth. This led to increased soil organic carbon, total nitrogen, and liable carbon at 30-50 cm depth, and increased autotrophic respiration of plants. Analysis shows that experimental warming influenced deeper root production via redistributed soil moisture, which favors the accumulation of belowground carbon, but did not significantly affected the decomposition of soil organic carbon. Our findings suggest that future climate change studies need to take greater consideration of changes in the hydrological cycle and the local ecosystem characteristics. The results of our study will aid in understanding the response of terrestrial ecosystems to climate change and provide the regional case for global ecosystem models.

No MeSH data available.


Related in: MedlinePlus

(A) Daily average air temperature and (B) Daily precipitation at the experimental site as well as (C) ground surface temperatures and (D) soil temperatures at 60 cm depth measured in the warmed (solid line) and control (dotted line) plots during the research period (1 July of 2010 to 1 July 2013).
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ece31685-fig-0001: (A) Daily average air temperature and (B) Daily precipitation at the experimental site as well as (C) ground surface temperatures and (D) soil temperatures at 60 cm depth measured in the warmed (solid line) and control (dotted line) plots during the research period (1 July of 2010 to 1 July 2013).

Mentions: Infrared heaters significantly (P < 0.001) increased the ground surface temperatures and soil temperatures at 60 cm depth by 2.31°C and 1.12°C in 2011, and 2.71°C and 0.41°C in 2012, respectively (Fig. 1C and D). The annual precipitations were 442 mm and 417.7 mm in 2011 and 2012. During the growing season (from May to September), the precipitations were 421.40 mm and 399.40 mm in 2011 and 2012 (Fig. 1B). Infrared heaters significantly (P < 0.001) decreased annual average soil volumetric moisture at 10 cm depth by 1.26% and 0.44% in 2011 and 2012, and significantly (P < 0.001) increased them at 60 cm depth by 4.26% and 4.97% in 2011 and 2012, respectively. From Figure 2, it can be seen that heater‐induced soil warming significantly (P < 0.01) increased average soil volumetric moisture in the deep layer (40–100 cm) over both years and the growing seasons of 2011 and 2012. There was no significant soil moisture change in the interlayer between top and deep layers. An elevated soil temperature significantly (P < 0.01) decreased soil volumetric moisture in the top layer in the growing seasons of both 2011 and 2012 as well as the whole year of 2011.


Belowground carbon responses to experimental warming regulated by soil moisture change in an alpine ecosystem of the Qinghai-Tibet Plateau.

Xue X, Peng F, You Q, Xu M, Dong S - Ecol Evol (2015)

(A) Daily average air temperature and (B) Daily precipitation at the experimental site as well as (C) ground surface temperatures and (D) soil temperatures at 60 cm depth measured in the warmed (solid line) and control (dotted line) plots during the research period (1 July of 2010 to 1 July 2013).
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4588646&req=5

ece31685-fig-0001: (A) Daily average air temperature and (B) Daily precipitation at the experimental site as well as (C) ground surface temperatures and (D) soil temperatures at 60 cm depth measured in the warmed (solid line) and control (dotted line) plots during the research period (1 July of 2010 to 1 July 2013).
Mentions: Infrared heaters significantly (P < 0.001) increased the ground surface temperatures and soil temperatures at 60 cm depth by 2.31°C and 1.12°C in 2011, and 2.71°C and 0.41°C in 2012, respectively (Fig. 1C and D). The annual precipitations were 442 mm and 417.7 mm in 2011 and 2012. During the growing season (from May to September), the precipitations were 421.40 mm and 399.40 mm in 2011 and 2012 (Fig. 1B). Infrared heaters significantly (P < 0.001) decreased annual average soil volumetric moisture at 10 cm depth by 1.26% and 0.44% in 2011 and 2012, and significantly (P < 0.001) increased them at 60 cm depth by 4.26% and 4.97% in 2011 and 2012, respectively. From Figure 2, it can be seen that heater‐induced soil warming significantly (P < 0.01) increased average soil volumetric moisture in the deep layer (40–100 cm) over both years and the growing seasons of 2011 and 2012. There was no significant soil moisture change in the interlayer between top and deep layers. An elevated soil temperature significantly (P < 0.01) decreased soil volumetric moisture in the top layer in the growing seasons of both 2011 and 2012 as well as the whole year of 2011.

Bottom Line: Our results show that 3 years of warming treatments significantly elevated soil temperature at 0-100 cm depth, decreased soil moisture at 10 cm depth, and increased soil moisture at 40-100 cm depth.In contrast to the findings of previous research, experimental warming did not significantly affect NH 4 (+)-N, NO 3 (-)-N, and heterotrophic respiration, but stimulated the growth of plants and significantly increased root biomass at 30-50 cm depth.Analysis shows that experimental warming influenced deeper root production via redistributed soil moisture, which favors the accumulation of belowground carbon, but did not significantly affected the decomposition of soil organic carbon.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 320 West Donggang Road Lanzhou 730000 China.

ABSTRACT
Recent studies found that the largest uncertainties in the response of the terrestrial carbon cycle to climate change might come from changes in soil moisture under the elevation of temperature. Warming-induced change in soil moisture and its level of influence on terrestrial ecosystems are mostly determined by climate, soil, and vegetation type and their sensitivity to temperature and moisture. Here, we present the results from a warming experiment of an alpine ecosystem conducted in the permafrost region of the Qinghai-Tibet Plateau using infrared heaters. Our results show that 3 years of warming treatments significantly elevated soil temperature at 0-100 cm depth, decreased soil moisture at 10 cm depth, and increased soil moisture at 40-100 cm depth. In contrast to the findings of previous research, experimental warming did not significantly affect NH 4 (+)-N, NO 3 (-)-N, and heterotrophic respiration, but stimulated the growth of plants and significantly increased root biomass at 30-50 cm depth. This led to increased soil organic carbon, total nitrogen, and liable carbon at 30-50 cm depth, and increased autotrophic respiration of plants. Analysis shows that experimental warming influenced deeper root production via redistributed soil moisture, which favors the accumulation of belowground carbon, but did not significantly affected the decomposition of soil organic carbon. Our findings suggest that future climate change studies need to take greater consideration of changes in the hydrological cycle and the local ecosystem characteristics. The results of our study will aid in understanding the response of terrestrial ecosystems to climate change and provide the regional case for global ecosystem models.

No MeSH data available.


Related in: MedlinePlus