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Gavazov K, Albrecht R, Buttler A, Dorrepaal E, Garnett MH, Gogo S, Hagedorn F, Mills RTE, Robroek BJM, Bragazza L. Vascular plant-mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change. GLOBAL CHANGE BIOLOGY 2018; 24:3911-3921. [PMID: 29569798 DOI: 10.1111/gcb.14140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Climate change can alter peatland plant community composition by promoting the growth of vascular plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a vascular plant-removal experiment in two Sphagnum-dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient. Periodic measurements of net ecosystem CO2 exchange revealed that vascular plants play a crucial role in assuring the potential for net carbon uptake, particularly with a warmer climate. The presence of vascular plants, however, also increased ecosystem respiration, and by using the seasonal variation of respired CO2 radiocarbon (bomb-14 C) signature we demonstrate an enhanced heterotrophic decomposition of peat carbon due to rhizosphere priming. The observed rhizosphere priming of peat carbon decomposition was matched by more advanced humification of dissolved organic matter, which remained apparent beyond the plant growing season. Our results underline the relevance of rhizosphere priming in peatlands, especially when assessing the future carbon sink function of peatlands undergoing a shift in vegetation community composition in association with climate change.
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Affiliation(s)
- Konstantin Gavazov
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Department of Ecology and Environmental Science, Climate Impacts Research Centre, Umeå University, Abisko, Sweden
| | - Remy Albrecht
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
| | - Alexandre Buttler
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Laboratoire de Chrono-Environnement, UMR CNRS 6249, UFR des Sciences et Techniques, Université de Franche-Comté, Besançon, France
| | - Ellen Dorrepaal
- Department of Ecology and Environmental Science, Climate Impacts Research Centre, Umeå University, Abisko, Sweden
| | - Mark H Garnett
- NERC Radiocarbon Facility (East Kilbride), East Kilbride, UK
| | - Sebastien Gogo
- ISTO, UMR 7327, Université d'Orléans, Orléans, France
- ISTO, UMR 7327, CNRS, Orléans, France
- ISTO, UMR 7327, BRGM, Orléans, France
| | - Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Birmensdorf, Birmensdorf, Switzerland
| | - Robert T E Mills
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Bjorn J M Robroek
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Biological Sciences, University of Southampton, Southampton, UK
| | - Luca Bragazza
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Lausanne, Switzerland
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Ecole Polytechnique Fédérale de Lausanne EPFL, Lausanne, Switzerland
- Department of Life Science and Biotechnologies, University of Ferrara, Ferrara, Italy
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Zheng Y, Waldron S, Flowers H. Fluvial dissolved organic carbon composition varies spatially and seasonally in a small catchment draining a wind farm and felled forestry. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 626:785-794. [PMID: 29396340 DOI: 10.1016/j.scitotenv.2018.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 12/25/2017] [Accepted: 01/01/2018] [Indexed: 06/07/2023]
Abstract
Assessing whether land use, from activities such as wind farm construction and tree-felling, impacts on terrestrial C delivery to rivers has focused on quantifying the loss of dissolved organic carbon (DOC), and not the composition changes. Here we explore how land use influences DOC composition by considering fluvial DOC concentration, [DOC], and spectrophotometric composition of a river draining a peat-rich catchment. We find that in this 5.7km2 catchment differences occur in both the concentration and composition of the DOC in its sub-catchments. This is attributed to differences in how land was used: one tributary (D-WF) drains an area with wind farm construction and forestry in the headwaters, and one tributary (D-FF) drains an area with felled plantation trees. Generally, [DOC] in both streams showed similar seasonal variation, and autumn maxima. However, the felled catchment had greater mean [DOC] than the wind farm catchment. The SUVA254 and E4/E6 indicated DOC in both streams had similar aromaticity and fulvic:humic acid for most of the time, but SUVA410 and E2/E4 indicated less DOC humification in the felled catchment. This may be due to young DOC from the breakdown of residual branches and roots, or more humification in soils in the wind farm area. During the dry months, DOC composition showed more spatial variation: the D-WF DOC had smaller SUVA254 (less total aromatic material) and SUVA410 (fewer humic substances). The decreased E2/E4 in both streams indicated the total aromatic carbon decreased more than humic substances content. Moreover, the larger E4/E6 for D-WF in summer indicated that the humic substances were richer in fulvic acids than humic acids. Soil disturbance associated with forestry-felling likely contributed to the higher [DOC] and release of less-humified material in D-FF. This research indicates drivers of different DOC concentration and composition can exist even in small catchments.
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Affiliation(s)
- Ying Zheng
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK; School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Susan Waldron
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Hugh Flowers
- School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
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Bragazza L, Buttler A, Robroek BJM, Albrecht R, Zaccone C, Jassey VEJ, Signarbieux C. Response to Editor to the comment by Delarue (2016) to our paper entitled 'Persistent high temperature and low precipitation reduce peat carbon accumulation'. GLOBAL CHANGE BIOLOGY 2017; 23:e7-e8. [PMID: 27862726 DOI: 10.1111/gcb.13559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Luca Bragazza
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015, Lausanne, Switzerland
- Department of Life Science and Biotechnologies, University of Ferrara, Corso Ercole I d'Este 32, 44121, Ferrara, Italy
| | - Alexandre Buttler
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015, Lausanne, Switzerland
- Laboratoire de Chrono-Environnement, UMR CNRS 6249, UFR des Sciences et Techniques, Université de Franche Comté, 25030, Besançon, France
| | - Bjorn J M Robroek
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015, Lausanne, Switzerland
| | - Remy Albrecht
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015, Lausanne, Switzerland
| | - Claudio Zaccone
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, via Napoli 25, 71122, Foggia, Italy
| | - Vincent E J Jassey
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015, Lausanne, Switzerland
| | - Constant Signarbieux
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, School of Architecture, Civil and Environmental Engineering ENAC, Laboratory of Ecological Systems ECOS, Station 2, 1015, Lausanne, Switzerland
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Bragazza L, Buttler A, Robroek BJM, Albrecht R, Zaccone C, Jassey VEJ, Signarbieux C. Persistent high temperature and low precipitation reduce peat carbon accumulation. GLOBAL CHANGE BIOLOGY 2016; 22:4114-4123. [PMID: 27081764 DOI: 10.1111/gcb.13319] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 04/04/2016] [Indexed: 05/27/2023]
Abstract
Extreme climate events are predicted to become more frequent and intense. Their ecological impacts, particularly on carbon cycling, can differ in relation to ecosystem sensitivity. Peatlands, being characterized by peat accumulation under waterlogged conditions, can be particularly sensitive to climate extremes if the climate event increases soil oxygenation. However, a mechanistic understanding of peatland responses to persistent climate extremes is still lacking, particularly in terms of aboveground-belowground feedback. Here, we present the results of a transplantation experiment of peat mesocosms from high to low altitude in order to simulate, during 3 years, a mean annual temperature c. 5 °C higher and a mean annual precipitation c. 60% lower. Specifically, we aim at understanding the intensity of changes for a set of biogeochemical processes and their feedback on carbon accumulation. In the transplanted mesocosms, plant productivity showed a species-specific response depending on plant growth forms, with a significant decrease (c. 60%) in peat moss productivity. Soil respiration almost doubled and Q10 halved in the transplanted mesocosms in combination with an increase in activity of soil enzymes. Spectroscopic characterization of peat chemistry in the transplanted mesocosms confirmed the deepening of soil oxygenation which, in turn, stimulated microbial decomposition. After 3 years, soil carbon stock increased only in the control mesocosms whereas a reduction in mean annual carbon accumulation of c. 30% was observed in the transplanted mesocosms. Based on the above information, a structural equation model was built to provide a mechanistic understanding of the causal connections between peat moisture, vegetation response, soil respiration and carbon accumulation. This study identifies, in the feedback between plant and microbial responses, the primary pathways explaining the reduction in carbon accumulation in response to recurring climate extremes in peat soils.
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Affiliation(s)
- Luca Bragazza
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Station 2, 1015, Lausanne, Switzerland
- Department of Life Science and Biotechnologies, University of Ferrara, Corso Ercole I d'Este 32, Ferrara, 44121, Italy
| | - Alexandre Buttler
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Station 2, 1015, Lausanne, Switzerland
- Laboratoire de Chrono-Environnement, UMR CNRS 6249, UFR des Sciences et Techniques, Université de Franche Comté, Besançon, 25030, France
| | - Bjorn J M Robroek
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Station 2, 1015, Lausanne, Switzerland
| | - Remy Albrecht
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Station 2, 1015, Lausanne, Switzerland
| | - Claudio Zaccone
- Department of the Sciences of Agriculture, Food and Environment, University of Foggia, via Napoli 25, 71122, Foggia, Italy
| | - Vincent E J Jassey
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Station 2, 1015, Lausanne, Switzerland
| | - Constant Signarbieux
- Swiss Federal Institute for Forest, Snow and Landscape Research, WSL Site Lausanne, Station 2, 1015, Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne EPFL, Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, Station 2, 1015, Lausanne, Switzerland
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