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Effects of substrate addition on soil respiratory carbon release under long-term warming and clipping in a tallgrass prairie.

Jia X, Zhou X, Luo Y, Xue K, Xue X, Xu X, Yang Y, Wu L, Zhou J - PLoS ONE (2014)

Bottom Line: We found that the addition of all three substrates significantly stimulated soil respiratory C release in all four warming and clipping treatments.In soils without substrate addition, warming significantly stimulated soil C release but clipping decreased it.Warming- and clipping-induced shifts in microbial metabolic capacity may be strongly associated with changes in plant species composition and could substantially influence soil C dynamics in response to global change.

View Article: PubMed Central - PubMed

Affiliation: Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; Shapotou Desert Research and Experimental Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, United States of America.

ABSTRACT
Regulatory mechanisms of soil respiratory carbon (C) release induced by substrates (i.e., plant derived substrates) are critical for predicting ecosystem responses to climate change, but the mechanisms are not well understood. In this study, we sampled soils from a long-term field manipulative experiment and conducted a laboratory incubation to explore the role of substrate supply in regulating the differences in soil C release among the experimental treatments, including control, warming, clipping, and warming plus clipping. Three types of substrates (glucose, C3 and C4 plant materials) were added with an amount equal to 1% of soil dry weight under the four treatments. We found that the addition of all three substrates significantly stimulated soil respiratory C release in all four warming and clipping treatments. In soils without substrate addition, warming significantly stimulated soil C release but clipping decreased it. However, additions of glucose and C3 plant materials (C3 addition) offset the warming effects, whereas C4 addition still showed the warming-induced stimulation of soil C release. Our results suggest that long-term warming may inhibit microbial capacity for decomposition of C3 litter but may enhance it for decomposition of C4 litter. Such warming-induced adaptation of microbial communities may weaken the positive C-cycle feedback to warming due to increased proportion of C4 species in plant community and decreased litter quality. In contrast, clipping may weaken microbial capacity for warming-induced decomposition of C4 litter but may enhance it for C3 litter. Warming- and clipping-induced shifts in microbial metabolic capacity may be strongly associated with changes in plant species composition and could substantially influence soil C dynamics in response to global change.

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Soil respiratory carbon (C) release represented by O2 depletion flux without additional substrate (a) and with the addition of glucose (b), C3 (c), and C4 (d) substrate under the four treatments: UC: unclipped control; UW: unclipped and warmed; CC: clipped control; CW: clipped and warmed.
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pone-0114203-g001: Soil respiratory carbon (C) release represented by O2 depletion flux without additional substrate (a) and with the addition of glucose (b), C3 (c), and C4 (d) substrate under the four treatments: UC: unclipped control; UW: unclipped and warmed; CC: clipped control; CW: clipped and warmed.

Mentions: In soils without substrate addition, warming significantly increased soil respiratory C release and clipping decreased it over the whole incubation period (p<0.05), although the respiration rates declined over time (Fig. 1a). The respiration rates in the CW plots were close to those in the UC plots at the initial incubation stages and to those in the UW plots at the later incubation stages. The difference in soil respiratory C release between the UW and UC plots was statistically significant (p<0.01), whereas that between CW and UW plots was not different (p>0.05, Figs. 2). Warming significantly increased soil respiratory C release by 13.6 and 35.6% in the unclipped (UW vs. UC) and clipped (CW vs. CC) plots, respectively (p<0.05, Fig. 2). Clipping decreased the respiratory rate by 23.89% (p<0.05, CC vs. UC) in the unwarmed treatment but the decrease was not significant in the warmed plots (9.16%, pā€Š=ā€Š0.10, CW vs. UW) over the incubation period (Fig. 3).


Effects of substrate addition on soil respiratory carbon release under long-term warming and clipping in a tallgrass prairie.

Jia X, Zhou X, Luo Y, Xue K, Xue X, Xu X, Yang Y, Wu L, Zhou J - PLoS ONE (2014)

Soil respiratory carbon (C) release represented by O2 depletion flux without additional substrate (a) and with the addition of glucose (b), C3 (c), and C4 (d) substrate under the four treatments: UC: unclipped control; UW: unclipped and warmed; CC: clipped control; CW: clipped and warmed.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260856&req=5

pone-0114203-g001: Soil respiratory carbon (C) release represented by O2 depletion flux without additional substrate (a) and with the addition of glucose (b), C3 (c), and C4 (d) substrate under the four treatments: UC: unclipped control; UW: unclipped and warmed; CC: clipped control; CW: clipped and warmed.
Mentions: In soils without substrate addition, warming significantly increased soil respiratory C release and clipping decreased it over the whole incubation period (p<0.05), although the respiration rates declined over time (Fig. 1a). The respiration rates in the CW plots were close to those in the UC plots at the initial incubation stages and to those in the UW plots at the later incubation stages. The difference in soil respiratory C release between the UW and UC plots was statistically significant (p<0.01), whereas that between CW and UW plots was not different (p>0.05, Figs. 2). Warming significantly increased soil respiratory C release by 13.6 and 35.6% in the unclipped (UW vs. UC) and clipped (CW vs. CC) plots, respectively (p<0.05, Fig. 2). Clipping decreased the respiratory rate by 23.89% (p<0.05, CC vs. UC) in the unwarmed treatment but the decrease was not significant in the warmed plots (9.16%, pā€Š=ā€Š0.10, CW vs. UW) over the incubation period (Fig. 3).

Bottom Line: We found that the addition of all three substrates significantly stimulated soil respiratory C release in all four warming and clipping treatments.In soils without substrate addition, warming significantly stimulated soil C release but clipping decreased it.Warming- and clipping-induced shifts in microbial metabolic capacity may be strongly associated with changes in plant species composition and could substantially influence soil C dynamics in response to global change.

View Article: PubMed Central - PubMed

Affiliation: Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China; Shapotou Desert Research and Experimental Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, United States of America.

ABSTRACT
Regulatory mechanisms of soil respiratory carbon (C) release induced by substrates (i.e., plant derived substrates) are critical for predicting ecosystem responses to climate change, but the mechanisms are not well understood. In this study, we sampled soils from a long-term field manipulative experiment and conducted a laboratory incubation to explore the role of substrate supply in regulating the differences in soil C release among the experimental treatments, including control, warming, clipping, and warming plus clipping. Three types of substrates (glucose, C3 and C4 plant materials) were added with an amount equal to 1% of soil dry weight under the four treatments. We found that the addition of all three substrates significantly stimulated soil respiratory C release in all four warming and clipping treatments. In soils without substrate addition, warming significantly stimulated soil C release but clipping decreased it. However, additions of glucose and C3 plant materials (C3 addition) offset the warming effects, whereas C4 addition still showed the warming-induced stimulation of soil C release. Our results suggest that long-term warming may inhibit microbial capacity for decomposition of C3 litter but may enhance it for decomposition of C4 litter. Such warming-induced adaptation of microbial communities may weaken the positive C-cycle feedback to warming due to increased proportion of C4 species in plant community and decreased litter quality. In contrast, clipping may weaken microbial capacity for warming-induced decomposition of C4 litter but may enhance it for C3 litter. Warming- and clipping-induced shifts in microbial metabolic capacity may be strongly associated with changes in plant species composition and could substantially influence soil C dynamics in response to global change.

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