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Belowground Response to Drought in a Tropical Forest Soil. I. Changes in Microbial Functional Potential and Metabolism.

Bouskill NJ, Wood TE, Baran R, Ye Z, Bowen BP, Lim H, Zhou J, Nostrand JD, Nico P, Northen TR, Silver WL, Brodie EL - Front Microbiol (2016)

Bottom Line: This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34).Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communities are sensitive to even small changes in soil water.Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon.

View Article: PubMed Central - PubMed

Affiliation: Earth Sciences Division, Ecology Department, Lawrence Berkeley National Laboratory Berkeley, CA, USA.

ABSTRACT
Global climate models predict a future of increased severity of drought in many tropical forests. Soil microbes are central to the balance of these systems as sources or sinks of atmospheric carbon (C), yet how they respond metabolically to drought is not well-understood. We simulated drought in the typically aseasonal Luquillo Experimental Forest, Puerto Rico, by intercepting precipitation falling through the forest canopy. This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34). Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communities are sensitive to even small changes in soil water. Here, we show prolonged drought significantly alters the functional potential of the community and provokes a clear osmotic stress response, including the production of compatible solutes that increase intracellular C demand. Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon. Significantly, some of these drought-induced functional shifts in the soil microbiota are attenuated by prior exposure to a short-term drought suggesting that acclimation may occur despite a lack of longer-term drought history.

No MeSH data available.


Related in: MedlinePlus

Hydrolytic enzyme activity across the control and treatment soil plots following 10 months of throughfall. The bar plots represent the mean (± standard deviation) of activities across the treatments (n = 5). Stars above the plots denote significant differences when compared with the control.
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Figure 3: Hydrolytic enzyme activity across the control and treatment soil plots following 10 months of throughfall. The bar plots represent the mean (± standard deviation) of activities across the treatments (n = 5). Stars above the plots denote significant differences when compared with the control.

Mentions: We subsequently asked whether significant changes in the functional potential of the soil microbial communities would be expressed as alterations in extracellular enzyme activity. We focused on the potential activity of enzymes related to depolymerization of plant and microbial macromolecules (BG, CBH, Xyl, NAG) following 10 months of drought. With the exception of NAG, enzyme activity was significantly higher in the de novo treatments relative to the control soils (two-way ANOVA, p < 0.05; Figure 3). Mean soil enzyme activities for BG, CBH, and Xyl were 40, 30, and 46% higher than the controls, respectively. Enzyme potential in the pre-excluded soils was generally elevated above the controls soils but lower than the de novo soils. No significant difference was noted between the pre-excluded and control soils.


Belowground Response to Drought in a Tropical Forest Soil. I. Changes in Microbial Functional Potential and Metabolism.

Bouskill NJ, Wood TE, Baran R, Ye Z, Bowen BP, Lim H, Zhou J, Nostrand JD, Nico P, Northen TR, Silver WL, Brodie EL - Front Microbiol (2016)

Hydrolytic enzyme activity across the control and treatment soil plots following 10 months of throughfall. The bar plots represent the mean (± standard deviation) of activities across the treatments (n = 5). Stars above the plots denote significant differences when compared with the control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837414&req=5

Figure 3: Hydrolytic enzyme activity across the control and treatment soil plots following 10 months of throughfall. The bar plots represent the mean (± standard deviation) of activities across the treatments (n = 5). Stars above the plots denote significant differences when compared with the control.
Mentions: We subsequently asked whether significant changes in the functional potential of the soil microbial communities would be expressed as alterations in extracellular enzyme activity. We focused on the potential activity of enzymes related to depolymerization of plant and microbial macromolecules (BG, CBH, Xyl, NAG) following 10 months of drought. With the exception of NAG, enzyme activity was significantly higher in the de novo treatments relative to the control soils (two-way ANOVA, p < 0.05; Figure 3). Mean soil enzyme activities for BG, CBH, and Xyl were 40, 30, and 46% higher than the controls, respectively. Enzyme potential in the pre-excluded soils was generally elevated above the controls soils but lower than the de novo soils. No significant difference was noted between the pre-excluded and control soils.

Bottom Line: This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34).Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communities are sensitive to even small changes in soil water.Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon.

View Article: PubMed Central - PubMed

Affiliation: Earth Sciences Division, Ecology Department, Lawrence Berkeley National Laboratory Berkeley, CA, USA.

ABSTRACT
Global climate models predict a future of increased severity of drought in many tropical forests. Soil microbes are central to the balance of these systems as sources or sinks of atmospheric carbon (C), yet how they respond metabolically to drought is not well-understood. We simulated drought in the typically aseasonal Luquillo Experimental Forest, Puerto Rico, by intercepting precipitation falling through the forest canopy. This approach reduced soil moisture by 13% and water potential by 0.14 MPa (from -0.2 to -0.34). Previous results from this experiment have demonstrated that the diversity and composition of these soil microbial communities are sensitive to even small changes in soil water. Here, we show prolonged drought significantly alters the functional potential of the community and provokes a clear osmotic stress response, including the production of compatible solutes that increase intracellular C demand. Subsequently, a microbial population emerges with a greater capacity for extracellular enzyme production targeting macromolecular carbon. Significantly, some of these drought-induced functional shifts in the soil microbiota are attenuated by prior exposure to a short-term drought suggesting that acclimation may occur despite a lack of longer-term drought history.

No MeSH data available.


Related in: MedlinePlus