Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests
Tropical dry forests are already undergoing changes in the quantity and timing of rainfall, but there is great uncertainty over how these shifts will affect belowground carbon (C) cycling. While it has long been known that dry soils quickly release carbon dioxide (CO _2 ) upon rewetting, the mechani...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2016-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/11/10/105005 |
| _version_ | 1797748726877388800 |
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| author | Bonnie G Waring Jennifer S Powers |
| author_facet | Bonnie G Waring Jennifer S Powers |
| author_sort | Bonnie G Waring |
| collection | DOAJ |
| description | Tropical dry forests are already undergoing changes in the quantity and timing of rainfall, but there is great uncertainty over how these shifts will affect belowground carbon (C) cycling. While it has long been known that dry soils quickly release carbon dioxide (CO _2 ) upon rewetting, the mechanisms underlying the so-called ‘Birch effect’ are still debated. Here, we quantified soil respiration pulses and their biotic predictors in response to simulated precipitation events in a regenerating tropical dry forest in Costa Rica. We also simulated the observed rewetting CO _2 pulses with two soil carbon models: a conventional model assuming first-order decay rates of soil organic matter, and an enzyme-catalyzed model with Michaelis–Menten kinetics. We found that rewetting of dry soils produced an immediate and dramatic pulse of CO _2 , accompanied by rapid immobilization of nitrogen into the microbial biomass. However, the magnitude of the rewetting CO _2 pulse was highly variable at fine spatial scales, and was well correlated with the size of the dissolved organic C pool prior to rewetting. Both the enzyme-catalyzed and conventional models were able to reproduce the Birch effect when respiration was coupled directly to microbial C uptake, although models differed in their ability to yield realistic estimates of SOC and microbial biomass pool sizes and dynamics. Our results suggest that changes in the timing and intensity of rainfall events in tropical dry forests will exert strong influence on ecosystem C balance by affecting the dynamics of microbial biomass growth. |
| first_indexed | 2024-03-12T16:08:59Z |
| format | Article |
| id | doaj.art-e1a294887f864bbd8aabd3deafd5bb5c |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:08:59Z |
| publishDate | 2016-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-e1a294887f864bbd8aabd3deafd5bb5c2023-08-09T14:13:10ZengIOP PublishingEnvironmental Research Letters1748-93262016-01-01111010500510.1088/1748-9326/11/10/105005Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forestsBonnie G Waring0Jennifer S Powers1Deptartment of Ecology, Evolution and Behavior, University of Minnesota , Saint Paul, MN 55108, USADeptartment of Ecology, Evolution and Behavior, University of Minnesota , Saint Paul, MN 55108, USA; Deptartment of Plant Biology, University of Minnesota , 1445 Gortner Ave, Saint Paul, MN 55108, USATropical dry forests are already undergoing changes in the quantity and timing of rainfall, but there is great uncertainty over how these shifts will affect belowground carbon (C) cycling. While it has long been known that dry soils quickly release carbon dioxide (CO _2 ) upon rewetting, the mechanisms underlying the so-called ‘Birch effect’ are still debated. Here, we quantified soil respiration pulses and their biotic predictors in response to simulated precipitation events in a regenerating tropical dry forest in Costa Rica. We also simulated the observed rewetting CO _2 pulses with two soil carbon models: a conventional model assuming first-order decay rates of soil organic matter, and an enzyme-catalyzed model with Michaelis–Menten kinetics. We found that rewetting of dry soils produced an immediate and dramatic pulse of CO _2 , accompanied by rapid immobilization of nitrogen into the microbial biomass. However, the magnitude of the rewetting CO _2 pulse was highly variable at fine spatial scales, and was well correlated with the size of the dissolved organic C pool prior to rewetting. Both the enzyme-catalyzed and conventional models were able to reproduce the Birch effect when respiration was coupled directly to microbial C uptake, although models differed in their ability to yield realistic estimates of SOC and microbial biomass pool sizes and dynamics. Our results suggest that changes in the timing and intensity of rainfall events in tropical dry forests will exert strong influence on ecosystem C balance by affecting the dynamics of microbial biomass growth.https://doi.org/10.1088/1748-9326/11/10/105005Birch effectprecipitationseasonalitysoil carbontropical dry forest |
| spellingShingle | Bonnie G Waring Jennifer S Powers Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests Environmental Research Letters Birch effect precipitation seasonality soil carbon tropical dry forest |
| title | Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests |
| title_full | Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests |
| title_fullStr | Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests |
| title_full_unstemmed | Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests |
| title_short | Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests |
| title_sort | unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests |
| topic | Birch effect precipitation seasonality soil carbon tropical dry forest |
| url | https://doi.org/10.1088/1748-9326/11/10/105005 |
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