Limits...
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

The relationships of (A) ΔRBM and (B) ΔNPP with ΔT and ΔSM. ΔRBM, ΔT, and ΔSM indicate infrared heater‐induced difference in root biomass, soil temperature, and soil moisture, respectively.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4588646&req=5

ece31685-fig-0006: The relationships of (A) ΔRBM and (B) ΔNPP with ΔT and ΔSM. ΔRBM, ΔT, and ΔSM indicate infrared heater‐induced difference in root biomass, soil temperature, and soil moisture, respectively.

Mentions: ΔT is infrared heater‐induced temperature difference (the values in the warmed plots minus that in the control plots, same hereafter), ΔSM is soil moisture difference, and ΔRBM is root biomass difference. From Figure 6A, it can be seen that ΔT did not cause the significant change (N = 5 × 5) for root biomass. In contrast, there was a significant (P < 0.05) quadratic exponential relation between ΔSM and ΔRBM. Root biomass increased with increased soil moisture in the deep layer. However, the increase in root biomass disappeared when infrared heaters caused soil moisture content to increase above 3%. There were no significant relations between ΔSM and ΔNPP or between ΔT and ΔNPP (Fig. 6B), although the total belowground NPP in the soil profile increased with the increased soil temperature (P = 0.148). However, the partial correlation analysis results show that when ΔT was held as the control factor (constant), ΔSM had a marginally significant (P = 0.052) relation with ΔNPP. When ΔSM was held as the control factor (constant), there was still no significant (P = 0.122) relation between ΔT and ΔNPP. The path analysis result (Table 3) also shows the indirect influence of soil temperature via soil moisture on belowground production.


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)

The relationships of (A) ΔRBM and (B) ΔNPP with ΔT and ΔSM. ΔRBM, ΔT, and ΔSM indicate infrared heater‐induced difference in root biomass, soil temperature, and soil moisture, respectively.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588646&req=5

ece31685-fig-0006: The relationships of (A) ΔRBM and (B) ΔNPP with ΔT and ΔSM. ΔRBM, ΔT, and ΔSM indicate infrared heater‐induced difference in root biomass, soil temperature, and soil moisture, respectively.
Mentions: ΔT is infrared heater‐induced temperature difference (the values in the warmed plots minus that in the control plots, same hereafter), ΔSM is soil moisture difference, and ΔRBM is root biomass difference. From Figure 6A, it can be seen that ΔT did not cause the significant change (N = 5 × 5) for root biomass. In contrast, there was a significant (P < 0.05) quadratic exponential relation between ΔSM and ΔRBM. Root biomass increased with increased soil moisture in the deep layer. However, the increase in root biomass disappeared when infrared heaters caused soil moisture content to increase above 3%. There were no significant relations between ΔSM and ΔNPP or between ΔT and ΔNPP (Fig. 6B), although the total belowground NPP in the soil profile increased with the increased soil temperature (P = 0.148). However, the partial correlation analysis results show that when ΔT was held as the control factor (constant), ΔSM had a marginally significant (P = 0.052) relation with ΔNPP. When ΔSM was held as the control factor (constant), there was still no significant (P = 0.122) relation between ΔT and ΔNPP. The path analysis result (Table 3) also shows the indirect influence of soil temperature via soil moisture on belowground production.

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