Por favor, use este identificador para citar o enlazar este ítem:
http://cicese.repositorioinstitucional.mx/jspui/handle/1007/1659| Exploring the "overflow tap" theory: linking forest soil CO2 fluxes and individual mycorrhizosphere components to photosynthesis | |
| Andreas Heinemeyer | |
| Matthew Wilkinson RODRIGO VARGAS RAMOS Jens_Arne Subke Eric Casella James Morrison Philip Ineson | |
| Acceso Abierto | |
| Atribución-NoComercial-SinDerivadas | |
| http://dx.doi.org/10.5194/bg-9-79-2012 | |
| Overflow tap, CO2, Soil organic carbon, Mycorrhizal component,Soil chambers | |
| "Quantifying soil organic carbon stocks (SOC) and their dynamics accurately is crucial for better predictions of climate change feedbacks within the atmosphere-vegetation soil system. However, the components, environmental responses and controls of the soil CO<sub>2</sub> efflux (R<sub>s</sub>) are still unclear and limited by field data availability. The objectives of this study were (1) to quantify the contribution of the various R<sub>s</sub> components, specifically its mycorrhizal component, (2) to determine their temporal variability, and (3) to establish their environmental responses and dependence on gross primary productivity (GPP). In a temperate deciduous oak forest in south east England hourly soil and ecosystem CO<sub>2</sub> fluxes over four years were measured using automated soil chambers and eddy covariance techniques. Mesh-bag and steel collar soil chamber treatments prevented root or both root and mycorrhizal hyphal in-growth, respectively, to allow separation of heterotrophic (R<sub>h</sub>) and autotrophic (R<sub>a</sub>) soil CO<sub>2</sub> fluxes and the R<sub>a</sub> components, roots (R<sub>r</sub>) and mycorrhizal hyphae (R<sub>m</sub>). Annual cumulative R<sub>s</sub> values were very similar between years (740 ± 43 g C m<sup>-2</sup> yr<sup>-1</sup> ) with an average flux of 2.0 ± 0.3 µmol CO<sub>2</sub> m<sup>-2</sup> s<sup>-1</sup> , but R<sub>s</sub> components varied. On average, annual R<sub>r</sub> , R<sub>m</sub> and R<sub>h</sub> fluxes contributed 38, 18 and 44 %, respectively, showing a large R<sub>a</sub> contribution (56 %) with a considerable R<sub>m</sub> component varying seasonally. Soil temperature largely explained the daily variation of R<sub>s</sub> (R<sup>2</sup> = 0.81), mostly because of strong responses by R<sub>h</sub> (R<sup>2</sup> = 0.65) and less so for R<sub>r</sub> (R<sup>2</sup> = 0.41) and R<sub>m</sub> (R<sup>2</sup> = 0.18). Time series analysis revealed strong daily periodicities for R<sub>s</sub> and R<sub>r</sub> , whilst R<sub>m</sub> was dominated by seasonal (~150 days), and R<sub>h</sub> by annual periodicities. Wavelet coherence analysis revealed that R<sub>r</sub> and R<sub>m</sub> were related to short-term (daily) GPP changes, but for R<sub>m</sub> there was a strong relationship with GPP over much longer (weekly to monthly) periods and notably during periods of low R<sub>r</sub> . The need to include individual R<sub>s</sub> components in C flux models is discussed, in particular, the need to represent the linkage between GPP and R<sub>a</sub> components, in addition to temperature responses for each component. The potential consequences of these findings for understanding the limitations for long-term forest C sequestration are highlighted, as GPP via root-derived C including R<sub>m</sub> seems to function as a C “overflow tap”, with implications on the turnover of SOC." | |
| Copernicus Publications | |
| 2012 | |
| Artículo | |
| Biogeosciences, Vol. 9, Págs. 79-95 | |
| Inglés | |
| Heinemeyer,A.,Wilkinson,M.,Vargas,R.,Subke,J.A.,Casella,E.,Morrison,J.I.L.,Ineson,P.2012.Exploring the “overflow tap” theory: linking forest soil CO2 fluxes and individual mycorrhizosphere components to photosynthesis.Biogeosciences,9,79-95.doi:10.5194/bg-9-79-2012 | |
| CIENCIAS DE LA VIDA | |
| Versión publicada | |
| publishedVersion - Versión publicada | |
| Aparece en las colecciones: | Artículos - Biología de la Conservación |
Cargar archivos:
| Fichero | Tamaño | Formato | |
|---|---|---|---|
| 151901.pdf | 9.03 kB | Adobe PDF | Visualizar/Abrir |