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Université de Neuchâtel

Above- and belowground linkages in Sphagnum peatland : climate warming affects plant-microbial interactions

Jassey, Vincent E. J. ; Chiapusio, Geneviève ; Binet, Philippe ; Buttler, Alexandre ; Laggoun-Défarge, Fatima ; Delarue, Frédéric ; Bernard, Nadine ; Mitchell, Edward A. D. ; Toussaint, Marie-Laure ; Francez, André-Jean ; Gilbert, Daniel

In: Global Change Biology, 2013, vol. 19, no. 3, p. 811-823

Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above- and belowground linkages that regulate soil organic carbon dynamics and C-balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and...

Université de Neuchâtel

Litter- and ecosystem-driven decomposition under elevated CO2 and enhanced N deposition in a Sphagnum peatland

Siegenthaler, Andy ; Buttler, Alexandre ; Bragazza, Luca ; van der Heijden, Edwin ; Grosvernier, Philippe ; Gobat, Jean-Michel ; Mitchell, Edward A. D.

In: Soil Biology and Biochemistry, 2010, vol. 42, no. 6, p. 968-977

Peatlands represent massive global C pools and sinks. Carbon accumulation depends on the ratio between net primary production and decomposition, both of which can change under projected increases of atmospheric CO2 and N deposition. The decomposition of litter is influenced by 1) the quality of the litter, and 2) the microenvironmental conditions in which the litter decomposes. This...

Université de Neuchâtel

Cut-over peatland regeneration assessment using organic matter and microbial indicators (bacteria and testate amoebae)

Laggoun-Défarge, Fatima ; Mitchell, Edward A. D. ; Gilbert, Daniel ; Disnar, Jean-Robert ; Comont, Laure ; Warner, Barry G. ; Buttler, Alexandre

In: Journal of Applied Ecology, 2007, vol. 45, no. 2, p. 716-727

1. Cut-over peatlands cover large surfaces of high potential value for enhancing biodiversity and carbon sequestration if successfully restored. Unfortunately, evaluation of restoration success is not straightforward. We assessed the bioindicator value of organic matter (OM), testate amoebae (protozoa) and bacteria in peat from two regeneration stages and a reference site of a cut-over...

Université de Neuchâtel

Functional microbial diversity in regenerating cutover peatlands responds to vegetation succession

Artz, Rebekka R. E. ; Chapman, Stephen J. ; Siegenthaler, Andy ; Mitchell, Edward A. D. ; Buttler, Alexandre ; Bortoluzzi, Estelle ; Gilbert, Daniel ; Yli-Petays, Mika ; Vasander, Harri ; Francez, André-Jean

In: Journal of Applied Ecology, 2008, vol. 45, no. 6, p. 1799-1809

1. While establishment of vegetation is the most visual indicator of regeneration on cutover peatland, the reinstatement of belowground functions is less well understood. Vegetation succession results in differences in peat quality in terms of C availability. The respiratory response of the soil microbial community to ecologically relevant substrates (community-level physiological profile,...

Université de Neuchâtel

Structure of microbial communities in Sphagnum peatlands and effect of atmospheric carbon dioxide enrichment

Mitchell, Edward A. D. ; Gilbert, Daniel ; Buttler, Alexandre ; Amblard, Christian ; Grosvernier, Philippe ; Gobat, Jean-Michel

In: Microbial Ecology, 2003, vol. 46, no. 2, p. 187-199

Little is known about the structure of microbial communities in Sphagnum peatlands, and the potential effects of the increasing atmospheric C02 concentration on these communities are not known. We analyzed the structure of microbial communities in five Sphagnum-dominated peatlands across Europe and their response to C02 enrichment using miniFACE systems. After...

Université de Neuchâtel

Horizontal Distribution Patterns of Testate Amoebae (Protozoa) in a Sphagnum magellanicum Carpet

Mitchell, Edward A. D. ; Borcard, Daniel ; Buttler, Alexandre J. ; Grosvernier, Philippe ; Gilbert, Daniel ; Gobat, Jean-Michel

In: Microbial Ecology, 2000, vol. 39, no. 4, p. 290-300

The distribution of soil microorganisms is generally believed to be patchy and to reflect habitat heterogeneity. Despite this general rule, the amount of existing data on species distribution patterns is scarce. Testate amoebae (Protozoa; Rhizopoda) are an important component of soil microbial communities and are increasingly used in ecological and paleoecological studies of...

Université de Neuchâtel

Le régime alimentaire des Thécamoebiens (Protista, Sarcodina)

Gilbert, Daniel ; Amblard, Christian ; Bourdier, Gilles ; Francez, André-Jean ; Mitchell, Edward A. D.

In: L’Année Biologique, 2000, vol. 39, no. 2, p. 57-68

Les amibes à thèques constituent un groupe de protozoaires libres, dont la caractéristique commune est la présence d'une thèque sur la morphologie de laquelle est basée une grande partie de la systématique. Leur détermination étant relativement aisée, ces microorganismes représentent une communauté de choix pour l'étude des écosystèmes, et sont des indicateurs biologiques de la...

Université de Neuchâtel

The palaeoecological history of the Praz-Rodet bog (Swiss Jura) based on pollen, plant macrofossils and testate amoebae (Protozoa)

Mitchell, Edward A. D. ; van der Knaap, W. O. ; van Leeuwen, Jacqueline F.N. ; Buttler, Alexandre ; Warner, Barry G. ; Gobat, Jean-Michel

In: The Holocene, 2001, vol. 11, no. 1, p. 65-80

Stratigraphy, radiocarbon dating and analyses of pollen, plant macrofossils and testate amoebae were used to reconstruct the development and ecology of a small raised bog in a karst-dominated landscape in the Swiss Jura Mountains. Special focus was on past vegetation and on the history of Pinus rotundata in relation to anthropogenic and climatic influences. Testate amoebae were used to...

Université de Neuchâtel

Effects of experimental warming on carbon sink function of a temperate pristine mire : the PEATWARM project

Laggoun-Défarge, Fatima ; Gilbert, Daniel ; Buttler, Alexandre ; Epron, Daniel ; Francez, Andre-Jean ; Grasset, Laurent ; Mitchell, Edward A. D. ; Guimbaud, Christophe ; Roy, J.-C.

In: Proceedings of the 13th International Peat Congress, 2008, p. 599-602

Within the PEATWARM project, we use Sphagnumpeatlands as a model to analyse their vulnerability to climate change using an experimental system (ITEX) that simulates in situan increase in average temperature. We aim to determine the effects of temperature increase on the vegetation, the balance of above- and belowground gas fluxes (CO2and CH4), the microbial diversity and activity in...

Université de Neuchâtel

Population Dynamics and Food Preferences of the Testate Amoeba Nebela tincta major-bohemica-collaris Complex (Protozoa) in a Sphagnum Peatland

Gilbert, Daniel ; Mitchell, Edward A. D. ; Bourdier, Gilles ; Francez, André-Jean

In: Acta protozoologica, 2003, vol. 42, no. 2, p. 99-104

Population dynamics and food preferences of the testate amoeba species complex Nebela tincta major-bohemica-collaris ("Nebela collaris sensu lato") were described from a Sphagnum peatland over one growing season. The average abundance of Nebela collaris sensu lato was 29582 ind. l-1 active, and 2263 ind. l-1 encysted forms. On average, 17.4% of Nebela...