Vascular plants affect properties and decomposition of moss-dominated peat, particularly at elevated temperatures

Autor(es)

Zeh, Lilli ^[1] ; Igel, Marie Theresa ^[1] ; Schellekens, Judith ^[2] ; Limpens, Juul ^[3] ; Bragazza, Luca ^[4] ; Kalbitz, Karsten ^[1]

Afiliação do(s) autor(es)

^[1] Tech Univ Dresden, Soil Resources & Land Use, Inst Soil Sci & Site Ecol, Pienner Str 19, D-01737 Tharandt - Germany

^[2] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz ESALQ, Dept Ciencia Solo, Av Padua Dias 11, Piracicaba, SP - Brazil

^[3] Wageningen Univ, Plant Ecol & Nat Conservat, Droevendaalse Steeg 3a, NL-6708 PB Wageningen - Netherlands

^[4] Agroscope, Plant Prod Syst, Route Duillier 50, POB 1012, CH-1260 Nyon - Switzerland

• Tipo de documento: Artigo Científico
• Fonte: BIOGEOSCIENCES; v. 17, n. 19, p. 4797-4813, OCT 5 2020.
• Citações Web of Science: 0

Resumo

Peatlands, storing significant amounts of carbon, are extremely vulnerable to climate change. The effects of climate change are projected to lead to a vegetation shift from Sphagnum mosses to sedges and shrubs. Impacts on the present moss-dominated peat remain largely unknown. In this study, we used a multiproxy approach to investigate the influence of contrasting vascular plant types (sedges, shrubs) on peat chemistry and decomposition. Peat cores of 20 cm depth and plant material (Sphagnum spp., Calluna vulgaris and Eriophorum vaginatum) from two ombrotrophic peatlands in the Italian Alps with a mean annual temperature difference of 1.4 degrees C were analyzed. Peat cores were taken under adjacent shrub and sedge plants growing at the same height above the water table. We used carbon, nitrogen and their stable isotopes to assess general patterns in the degree of decomposition across sampling locations and depths. In addition, analytical pyrolysis was applied to disentangle effects of vascular plants (sedge, shrub) on chemical properties and decomposition of the moss-dominated peat. Pyrolysis data confirmed that Sphagnum moss dominated the present peat irrespective of depth. Nevertheless, vascular plants contributed to peat properties as revealed by, e.g., pyrolysis products of lignin. The degree of peat decomposition increased with depth as shown by, e.g., decreasing amounts of the pyrolysis product of sphagnum acid and increasing delta C-13 with depth. Multiple parameters also revealed a higher degree of decomposition of Sphagnum-dominated peat collected under sedges than under shrubs, particularly at the high temperature site. Surprisingly, temperature effects on peat decomposition were less pronounced than those of sedges. Our results imply that vascular plants affect the decomposition of the existing peat formed by Sphagnum, particularly at elevated temperature. These results suggest that changes in plant functional types may have a stronger impact on the soil carbon feedback in a warmer world than hitherto assumed. (AU)

• Processo FAPESP: 13/03953-9 - Dinâmica da matéria orgânica em organossolos de turfeiras tropicais (Diamantina-MG, Brasil) - desenvolvimento de proxies moleculares para a reconstrução de mudanças paleoambientais
• Beneficiário: Judith Schellekens
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado