Natural abundance of 13C in CO2 respired from forest soils reveals speed of link between tree photosynthesis and root respiration

Ekblad, Alf; Högberg, Peter

doi:10.1007/s004420100667

Cited by 392 publications

(343 citation statements)

References 20 publications

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“…Vegetation affects carbon cycling directly through photosynthesis (Raich and Schlesinger, 1992;Ekblad and Högberg, 2001;Högberg et al, 2001), above-and belowground tissue allocation (Chen et al, 2013), and litter production (PrevostBoure et al, 2010). Vegetation therefore controls the quantity and quality of soil organic matter (SOM) within systems, which in part will determine decomposition rates and soil CO 2 production (e.g., Berg, 2000).…”

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed

2015

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Abstract. In topographically complex watersheds, landscape position and vegetation heterogeneity can alter the soil water regime through both lateral and vertical redistribution, respectively. These alterations of soil moisture may have significant impacts on the spatial heterogeneity of biogeochemical cycles throughout the watershed. To evaluate how landscape position and vegetation heterogeneity affect soil CO 2 efflux (F SOIL ), we conducted observations across the Weimer Run watershed (373 ha), located near Davis, West Virginia, for three growing seasons with varying precipitation. An apparent soil temperature threshold of 11 • C for F SOIL at 12 cm depth was observed in our data, where F SOIL rates greatly increase in variance above this threshold. We therefore focus our analyses of F SOIL on instances in which soil temperature values were above this threshold. Vegetation had the greatest effect on F SOIL rates, with plots beneath shrubs at all elevations, for all years, showing the greatest mean rates of F SOIL (6.07 µmol CO 2 m −2 s −1 ) compared to plots beneath closedforest canopy (4.69 µmol CO 2 m −2 s −1 ) and plots located in open, forest gap (4.09 µmol CO 2 m −2 s −1 ) plots. During periods of high soil moisture, we find that CO 2 efflux rates are constrained, and that maximum efflux rates occur during periods of average to below-average soil water availability. While vegetation was the variable most related to F SOIL , there is also strong interannual variability in fluxes determined by the interaction of annual precipitation and topography. These findings add to the current theoretical constructs related to the interactions of moisture and vegetation in biogeochemical cycles within topographically complex watersheds.

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Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed

2015

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“…Therefore, in simulating R eco across the whole season, the impact of canopy photosynthesis activity must be taken into account (Janssens et al, 2001). Most recent results have shown that there is a time lag for R eco to respond the change in photosynthesis (Ekbald and Högberg, 2001;Bowling et al, 2002), making it more challenging to model ecosystem respiration. .…”

Section: Gpp In Relation To Lai and R Ecomentioning

confidence: 99%

Seasonal variation in carbon dioxide exchange over a Mediterranean annual grassland in California

Baldocchi

2004

Agricultural and Forest Meteorology

547

350

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Understanding how environmental variables affect the processes that regulate the carbon flux over grassland is critical for large-scale modeling research, since grasslands comprise almost one-third of the earth's natural vegetation. To address this issue, fluxes of CO 2 (F c , flux toward the surface is negative) were measured over a Mediterranean, annual grassland in California, USA for 2 years with the eddy covariance method.To interpret the biotic and abiotic factors that modulate F c over the course of a year we decomposed net ecosystem CO 2 exchange into its constituent components, ecosystem respiration (R eco ) and gross primary production (GPP). Daytime R eco was extrapolated from the relationship between temperature and nighttime F c under high turbulent conditions. Then, GPP was estimated by subtracting daytime values of F c from daytime estimates of R eco .Results show that most of carbon exchange, both photosynthesis and respiration, was limited to the wet season (typically from October to mid-May). Seasonal variations in GPP followed closely to changes in leaf area index, which in turn was governed by soil moisture, available sunlight and the timing of the last frost. In general, R eco was an exponential function of soil temperature, but with season-dependent values of Q 10 . The temperature-dependent respiration model failed immediately after rain events, when large pulses of R eco were observed. Respiration pulses were especially notable during the dry season when the grass was dead and were the consequence of quickly stimulated microbial activity.Integrated values of GPP, R eco , and net ecosystem exchange (NEE) were 867, 735, and −132 g C m −2 , respectively, for the 2000-2001 season, and 729, 758, and 29 g C m −2 for the 2001-2002 season. Thus, the grassland was a moderate carbon sink during the first season and a weak carbon source during the second season. In contrast to a well-accepted view that annual production of grass is linearly correlated to precipitation, the large difference in GPP between the two seasons were not caused by the annual precipitation. Instead, a shorter growing season, due to late start of the rainy season, was mainly responsible for the lower GPP in the second season. Furthermore, relatively higher R eco during the non-growing season occurred after a late spring rain. Thus, for this Mediterranean grassland, the timing of rain events had more impact than the total amount of precipitation on ecosystem GPP and NEE. This is because its growing season is in the cool and wet season when carbon uptake and respiration are usually limited by low temperature and sometimes frost, not by soil moisture.

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“…Therefore several authors have hypothesized that global warming and changes in rainfall amount and distribution might influence soil respiration and the capacity of the soil to sequester carbon [38,45]. However, recent studies have found soil respiration to be mainly driven by newly produced photosynthates and weather conditions [3,18,19,26].…”

Section: Introductionmentioning

confidence: 99%

Soil carbon dioxide efflux in pure and mixed stands of oak and beech

et al. 2007

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-Total Soil Respiration (TSR) was measured in pure and mixed stands of oak and beech and was partitioned into two contributions using the forest floor removal technique: Mineral Soil Respiration (MSR) and Forest Floor Respiration (FFR). In addition, laboratory incubations of the forest floor and the Ah horizon were performed to evaluate the heterotrophic respiration and the DOC production of these horizons. The relationships between soil temperature and the various soil respiration contributions in the three stands were compared using Q 10 functions. In situ, significant differences (α = 0,05) between stands were observed for the R 10 parameter (respiration rate at 10 • C) of the TSR, MSR and FFR contributions, while only the temperature sensitivity (Q 10 ) of TSR was significantly affected by stand composition. The effect of soil water content was only significant on MSR and followed different patterns according to stand composition. Under controlled conditions, the R 10 of the forest floor and of the Ah horizon varied with stand composition and the Q 10 of the forest floor decreased in the order: oak (2.27) > mixture (2.01) > beech (1.71).soil respiration / partitioning / species effect / mixed stand / abiotic factors Résumé -Flux de CO 2 en provenance du sol en peuplements purs et mélangés de chêne et de hêtre. La respiration totale du sol (RTS) a été mesurée en peuplements purs et mélangés de chêne et de hêtre et a été subdivisée en deux contributions en enlevant les couches holorganiques de certaines zones de mesure (RSM : respiration du sol minéral et RCH : respiration des couches holorganiques). De plus, des échantillons de couches holorganiques et d'horizon Ah ont été incubés en laboratoire pour évaluer la respiration hétérotrophique et la production de DOC de ces horizons. Des fonctions Q 10 ont été utilisées pour comparer les trois peuplements au niveau de la réponse à la température des différentes contributions à RTS. In situ, des différences significatives (α = 0.05) entre peuplements ont été mises en évidence en ce qui concerne le paramètre R 10 (flux à 10 • C) de toutes les contributions (RTS, RSM, RCH) et la sensibilité à la température (Q 10 ) de RTS uniquement. L'effet de la teneur en eau du sol était seulement significatif sur RSM et variait en fonction de la composition spécifique du peuplement. En conditions contrôlées, le paramètre R 10 des couches holorganiques et de l'horizon Ah était significativement influencé par la composition spécifique ; la respiration hétérotrophique des couches holorganiques présentait une sensibilité à la température décroissant suivant l'ordre : chênaie (2,27) > mélange (2,01) > hêtraie (1,71). respiration du sol / effet espèce / peuplement mélangé / facteurs abiotiques

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Natural abundance of 13C in CO2 respired from forest soils reveals speed of link between tree photosynthesis and root respiration

Cited by 392 publications

References 20 publications

Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed

Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed

Seasonal variation in carbon dioxide exchange over a Mediterranean annual grassland in California

Soil carbon dioxide efflux in pure and mixed stands of oak and beech

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Natural abundance of 13C in CO2 respired from forest soils reveals speed of link between tree photosynthesis and root respiration

Cited by 392 publications

References 20 publications

Vegetation and elevation influence the timing and magnitude of soil CO&lt;sub&gt;2&lt;/sub&gt; efflux in a humid, topographically complex watershed

Vegetation and elevation influence the timing and magnitude of soil CO&lt;sub&gt;2&lt;/sub&gt; efflux in a humid, topographically complex watershed

Seasonal variation in carbon dioxide exchange over a Mediterranean annual grassland in California

Soil carbon dioxide efflux in pure and mixed stands of oak and beech

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Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed

Vegetation and elevation influence the timing and magnitude of soil CO<sub>2</sub> efflux in a humid, topographically complex watershed