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Seasonality, Rather than Nutrient Addition or Vegetation Types, Influenced Short-Term Temperature Sensitivity of Soil Organic Carbon Decomposition.

Qian YQ, He FP, Wang W - PLoS ONE (2016)

Bottom Line: The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio.Microbial respiration (or Q10) did not significantly respond to N or P addition.Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China.

ABSTRACT
The response of microbial respiration from soil organic carbon (SOC) decomposition to environmental changes plays a key role in predicting future trends of atmospheric CO2 concentration. However, it remains uncertain whether there is a universal trend in the response of microbial respiration to increased temperature and nutrient addition among different vegetation types. In this study, soils were sampled in spring, summer, autumn and winter from five dominant vegetation types, including pine, larch and birch forest, shrubland, and grassland, in the Saihanba area of northern China. Soil samples from each season were incubated at 1, 10, and 20°C for 5 to 7 days. Nitrogen (N; 0.035 mM as NH4NO3) and phosphorus (P; 0.03 mM as P2O5) were added to soil samples, and the responses of soil microbial respiration to increased temperature and nutrient addition were determined. We found a universal trend that soil microbial respiration increased with increased temperature regardless of sampling season or vegetation type. The temperature sensitivity (indicated by Q10, the increase in respiration rate with a 10°C increase in temperature) of microbial respiration was higher in spring and autumn than in summer and winter, irrespective of vegetation type. The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio. Microbial respiration (or Q10) did not significantly respond to N or P addition. Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer.

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Relationship between Q10 of soil microbial respiration and fungal: bacterial biomass ratio.Data are from all the nutrient treatment combinations, vegetation types, and seasons.
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pone.0153415.g004: Relationship between Q10 of soil microbial respiration and fungal: bacterial biomass ratio.Data are from all the nutrient treatment combinations, vegetation types, and seasons.

Mentions: When incubated at the same temperature, soil sampled from different seasons presented significantly different respiration rates (Fig 2). At 1°C, even though summer and winter soil had higher respiration rates than spring and autumn soil (P <0.05), the absolute respiration rates of all four seasons were very low. At 10 and 20°C, spring soil had a higher respiration rate than any other soil (P < 0.05). Temperature sensitivities of soil microbial respiration, expressed as Q10, were 3.13 (spring, R2 = 0.584, P < 0.001), 1.35 (summer, R2 = 0.076, P < 0.001), 2.78 (autumn, R2 = 0.521, P < 0.001), and 1.45 (winter, R2 = 0.179, P < 0.001). Soils from all of the five vegetation types showed higher Q10 in spring and autumn than in summer and winter. The seasonal pattern in Q10 was significantly correlated with microbial biomass (Y = 0.06 X + 1.01; R2 = 0.60, P = 0.02, Fig 3) and fungal: bacterial biomass ratio (Y = 18.93 X + 0.32; R2 = 0.82; P < 0.01, Fig 4).


Seasonality, Rather than Nutrient Addition or Vegetation Types, Influenced Short-Term Temperature Sensitivity of Soil Organic Carbon Decomposition.

Qian YQ, He FP, Wang W - PLoS ONE (2016)

Relationship between Q10 of soil microbial respiration and fungal: bacterial biomass ratio.Data are from all the nutrient treatment combinations, vegetation types, and seasons.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829267&req=5

pone.0153415.g004: Relationship between Q10 of soil microbial respiration and fungal: bacterial biomass ratio.Data are from all the nutrient treatment combinations, vegetation types, and seasons.
Mentions: When incubated at the same temperature, soil sampled from different seasons presented significantly different respiration rates (Fig 2). At 1°C, even though summer and winter soil had higher respiration rates than spring and autumn soil (P <0.05), the absolute respiration rates of all four seasons were very low. At 10 and 20°C, spring soil had a higher respiration rate than any other soil (P < 0.05). Temperature sensitivities of soil microbial respiration, expressed as Q10, were 3.13 (spring, R2 = 0.584, P < 0.001), 1.35 (summer, R2 = 0.076, P < 0.001), 2.78 (autumn, R2 = 0.521, P < 0.001), and 1.45 (winter, R2 = 0.179, P < 0.001). Soils from all of the five vegetation types showed higher Q10 in spring and autumn than in summer and winter. The seasonal pattern in Q10 was significantly correlated with microbial biomass (Y = 0.06 X + 1.01; R2 = 0.60, P = 0.02, Fig 3) and fungal: bacterial biomass ratio (Y = 18.93 X + 0.32; R2 = 0.82; P < 0.01, Fig 4).

Bottom Line: The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio.Microbial respiration (or Q10) did not significantly respond to N or P addition.Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871, China.

ABSTRACT
The response of microbial respiration from soil organic carbon (SOC) decomposition to environmental changes plays a key role in predicting future trends of atmospheric CO2 concentration. However, it remains uncertain whether there is a universal trend in the response of microbial respiration to increased temperature and nutrient addition among different vegetation types. In this study, soils were sampled in spring, summer, autumn and winter from five dominant vegetation types, including pine, larch and birch forest, shrubland, and grassland, in the Saihanba area of northern China. Soil samples from each season were incubated at 1, 10, and 20°C for 5 to 7 days. Nitrogen (N; 0.035 mM as NH4NO3) and phosphorus (P; 0.03 mM as P2O5) were added to soil samples, and the responses of soil microbial respiration to increased temperature and nutrient addition were determined. We found a universal trend that soil microbial respiration increased with increased temperature regardless of sampling season or vegetation type. The temperature sensitivity (indicated by Q10, the increase in respiration rate with a 10°C increase in temperature) of microbial respiration was higher in spring and autumn than in summer and winter, irrespective of vegetation type. The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio. Microbial respiration (or Q10) did not significantly respond to N or P addition. Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer.

Show MeSH
Related in: MedlinePlus