From biota to chemistry and climate: towards a comprehensive description of trace gas exchange between the biosphere and atmosphere

Arneth, Almut; Sitch, Stephen; Bondeau, Alberte; Butterbach‐Bahl, Klaus; Foster, P. N.; Gedney, Nicola; Noblet‐Ducoudré, Nathalie de; Prentice, I. Colin; Sanderson, Michael; Thonicke, Kirsten; Wania, R.; Zaehle, Sönke

doi:10.5194/bg-7-121-2010

Cited by 97 publications

(88 citation statements)

References 307 publications

(355 reference statements)

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“…The Arctic is one of the most susceptible regions on Earth to climate change (e.g., Serreze et al, 2000;Polyakov et al, 2003;Fyfe et al, 2013;Pithan and Mauritsen, 2014), and altered climate conditions may have enormous consequences for the sustainability of its natural environment (Schuur et al, 2008;Arneth et al, 2010). Interactions between permafrost, climate, hydrology, and ecology have the potential to cause dramatic changes (e.g., McGuire et al, 2002;Hinzman et al, 2005) via mechanisms that are currently poorly monitored and therefore highly unpredictable (Heimann and Reichstein, 2008;van Huissteden and Dolman, 2012;Rawlins et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

et al. 2017

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Abstract. Hydrologic conditions are a key factor in Arctic ecosystems, with strong influences on ecosystem structure and related effects on biogeophysical and biogeochemical processes. With systematic changes in water availability expected for large parts of the northern high-latitude region in the coming centuries, knowledge on shifts in ecosystem functionality triggered by altered water levels is crucial for reducing uncertainties in climate change predictions. Here, we present findings from paired ecosystem observations in northeast Siberia comprising a drained and a control site. At the drainage site, the water table has been artificially lowered by up to 30 cm in summer for more than a decade. This sustained primary disturbance in hydrologic conditions has triggered a suite of secondary shifts in ecosystem properties, including vegetation community structure, snow cover dynamics, and radiation budget, all of which influence the net effects of drainage. Reduced thermal conductivity in dry organic soils was identified as the dominating drainage effect on energy budget and soil thermal regime. Through this effect, reduced heat transfer into deeper soil layers leads to shallower thaw depths, initially leading to a stabilization of organic permafrost soils, while the long-term effects on permafrost temperature trends still need to be assessed. At the same time, more energy is transferred back into the atmosphere as sensible heat in the drained area, which may trigger a warming of the lower atmospheric surface layer.

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Section: Introductionmentioning

confidence: 99%

Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

et al. 2017

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“…satellite observations), an atmospheric transport model and prior estimates of source distributions and magnitudes (Arneth et al, 2010;EPA, 2010;Kirschke et al, 2013). The first approach can be unreliable in scaling from point measurements up to regional or global scales due to limitations in spatial and temporal coverage of measurements (Cao et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…These uncertainties are generally introduced from large temporal and spatial variations in CH 4 flux, with the complex processes that underlie CH 4 emissions and also the limited inherent range of field and laboratory measurements (Arneth et al, 2010;Wania et al, 2010;Spahni et al, 2011;Meng et al, 2012). Therefore, further development of process-based CH 4 emission models is critical (Walter and Heimann, 2000;Ito and Inatomi, 2012).…”

Section: Introductionmentioning

confidence: 99%

Modelling methane emissions from natural wetlands by development and application of the TRIPLEX-GHG model

et al. 2014

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Abstract.A new process-based model TRIPLEX-GHG was developed based on the Integrated Biosphere Simulator (IBIS), coupled with a new methane (CH 4 ) biogeochemistry module (incorporating CH 4 production, oxidation, and transportation processes) and a water table module to investigate CH 4 emission processes and dynamics that occur in natural wetlands. Sensitivity analysis indicates that the most sensitive parameters to evaluate CH 4 emission processes from wetlands are r (defined as the CH 4 to CO 2 release ratio) and Q 10 in the CH 4 production process. These two parameters were subsequently calibrated to data obtained from 19 sites collected from approximately 35 studies across different wetlands globally. Being heterogeneously spatially distributed, r ranged from 0.1 to 0.7 with a mean value of 0.23, and the Q 10 for CH 4 production ranged from 1.6 to 4.5 with a mean value of 2.48. The model performed well when simulating magnitude and capturing temporal patterns in CH 4 emissions from natural wetlands. Results suggest that the model is able to be applied to different wetlands under varying conditions and is also applicable for global-scale simulations.

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“…Vegetation and ecosystem net productivity are determined by carbon losses through autotrophic and heterotrophic respiration. A set of allocation rules determines the carbon allocated to canopy growth, as well as to litter input into soils (for details see: Arneth et al, 2010b;Cramer et al, 1999;Prentice et al, 2007;Sitch et al, 2008). Modelling tree-grass coexistence is important to correctly simulate the gradient from closed forests, through woodlands, savannas, and grasslands, and has been shown to be a challenge for many DGVMs (Cramer et al, 1999;Scheiter and Higgins, 2009).…”

Section: Dgvm-based Estimates Of Gross Fluxes and Net Ecosystem Produmentioning

confidence: 99%

A full greenhouse gases budget of Africa: synthesis, uncertainties, and vulnerabilities

et al. 2014

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Abstract. This paper, developed under the framework of the RECCAP initiative, aims at providing improved estimates of the carbon and GHG (CO 2 , CH 4 and N 2 O) balance of continental Africa. The various components and processes of the African carbon and GHG budget are considered, existing data reviewed, and new data from different methodologies (inventories, ecosystem flux measurements, models, and atmospheric inversions) presented. Uncertainties are quantified and current gaps and weaknesses in knowledge and monitoring systems described in order to guide future requirements. The majority of results agree that Africa is a small sink of carbon on an annual scale, with an average value of Published by Copernicus Publications on behalf of the European Geosciences Union. R. Valentini et al.: A full greenhouse gases budget of Africa−0.61 ± 0.58 Pg C yr −1 . Nevertheless, the emissions of CH 4 and N 2 O may turn Africa into a net source of radiative forcing in CO 2 equivalent terms. At sub-regional level, there is significant spatial variability in both sources and sinks, due to the diversity of biomes represented and differences in the degree of anthropic impacts. Southern Africa is the main source region; while central Africa, with its evergreen tropical forests, is the main sink. Emissions from land-use change in Africa are significant (around 0.32 ± 0.05 Pg C yr −1 ), even higher than the fossil fuel emissions: this is a unique feature among all the continents. There could be significant carbon losses from forest land even without deforestation, resulting from the impact of selective logging. Fires play a significant role in the African carbon cycle, with 1.03 ± 0.22 Pg C yr −1 of carbon emissions, and 90 % originating in savannas and dry woodlands. A large portion of the wild fire emissions are compensated by CO 2 uptake during the growing season, but an uncertain fraction of the emission from wood harvested for domestic use is not. Most of these fluxes have large interannual variability, on the order of ±0.5 Pg C yr −1 in standard deviation, accounting for around 25 % of the year-toyear variation in the global carbon budget.Despite the high uncertainty, the estimates provided in this paper show the important role that Africa plays in the global carbon cycle, both in terms of absolute contribution, and as a key source of interannual variability.

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From biota to chemistry and climate: towards a comprehensive description of trace gas exchange between the biosphere and atmosphere

Cited by 97 publications

References 307 publications

Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

Modelling methane emissions from natural wetlands by development and application of the TRIPLEX-GHG model

A full greenhouse gases budget of Africa: synthesis, uncertainties, and vulnerabilities

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