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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 diagram for the responses of belowground C processes to experimental warming in permafrost region. ↑: positive response and increase to warming; ↓: negative response and decrease to warming; vertical dot line is no significant change. *indicates statistical significance at the level of P < 0.05, ** indicates statistical significance at the level of P < 0.01. T is soil temperature; M is soil moisture; RBM is root biomass; Rs is soil respiration; Rh and Ra are heterotrophic and autotrophic respiration; SOC is soil organic carbon; LC is labile carbon; TN is total nitrogen; NH4+‐N is ammonium nitrogen; NO3−‐N is nitrate nitrogen.
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ece31685-fig-0007: A diagram for the responses of belowground C processes to experimental warming in permafrost region. ↑: positive response and increase to warming; ↓: negative response and decrease to warming; vertical dot line is no significant change. *indicates statistical significance at the level of P < 0.05, ** indicates statistical significance at the level of P < 0.01. T is soil temperature; M is soil moisture; RBM is root biomass; Rs is soil respiration; Rh and Ra are heterotrophic and autotrophic respiration; SOC is soil organic carbon; LC is labile carbon; TN is total nitrogen; NH4+‐N is ammonium nitrogen; NO3−‐N is nitrate nitrogen.

Mentions: All of these patterns and analytic results indicate that experimental warming did not significantly change the decomposition process but instead affected plant belowground production processes which depend more on increasing soil moisture (Fig. 7). This pattern can be explained by the seasonal freeze–thaw process. After the midpoint of July in every year, heating caused soil moisture in the deeper soil layer to increase beyond field moisture capacity which created anoxic conditions in the deeper soil and inhibited decomposition.


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 diagram for the responses of belowground C processes to experimental warming in permafrost region. ↑: positive response and increase to warming; ↓: negative response and decrease to warming; vertical dot line is no significant change. *indicates statistical significance at the level of P < 0.05, ** indicates statistical significance at the level of P < 0.01. T is soil temperature; M is soil moisture; RBM is root biomass; Rs is soil respiration; Rh and Ra are heterotrophic and autotrophic respiration; SOC is soil organic carbon; LC is labile carbon; TN is total nitrogen; NH4+‐N is ammonium nitrogen; NO3−‐N is nitrate nitrogen.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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ece31685-fig-0007: A diagram for the responses of belowground C processes to experimental warming in permafrost region. ↑: positive response and increase to warming; ↓: negative response and decrease to warming; vertical dot line is no significant change. *indicates statistical significance at the level of P < 0.05, ** indicates statistical significance at the level of P < 0.01. T is soil temperature; M is soil moisture; RBM is root biomass; Rs is soil respiration; Rh and Ra are heterotrophic and autotrophic respiration; SOC is soil organic carbon; LC is labile carbon; TN is total nitrogen; NH4+‐N is ammonium nitrogen; NO3−‐N is nitrate nitrogen.
Mentions: All of these patterns and analytic results indicate that experimental warming did not significantly change the decomposition process but instead affected plant belowground production processes which depend more on increasing soil moisture (Fig. 7). This pattern can be explained by the seasonal freeze–thaw process. After the midpoint of July in every year, heating caused soil moisture in the deeper soil layer to increase beyond field moisture capacity which created anoxic conditions in the deeper soil and inhibited decomposition.

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