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Accès public à partir du 1 avr. 2019
Université de Neuchâtel

Palaeoecology of Sphagnum riparium (Ångström) in Northern Hemisphere peatlands : Implications for peatland conservation and palaeoecological research

Gałka, Mariusz ; Galloway, Jennifer M ; Lemonis, Natalie ; Mazei, Yuri A ; Mitchell, Edward A.D ; Morse, Peter D ; Patterson, Timothy R ; Tsyganov, Andrey N ; Wolfe, Stephen A ; Swindles, Graeme T

In: Review of Palaeobotany and Palynology, 2018, vol. 254, p. 1-7

Sphagnum riparium (Ångström) is a rare constituent of modern peatland plant communities and is also very rarely found as a subfossil in peat archives. We present new data on the occurrence of Sphagnum riparium macrofossils in three Northern Hemisphere peatlands from Yellowknife (NWCanada), Abisko (N Sweden), and the Northern Ural Mountains (NWRussia). Sphagnum riparium...

Université de Neuchâtel

Response of Sphagnum Testate Amoebae to Drainage, Subsequent Re-wetting and Associated Changes in the Moss Carpet : Results from a Three Year Mesocosm Experiment

Koenig, Isabelle ; Schwendener, Florence ; Mulot, Matthieu ; Mitchell, Edward A.D

In: Acta Protozoologica, 2017, vol. 56, no. 3, p. 191-210

Sphagnum peatlands represent a globally significant pool and sink of carbon but these functions are threatened by ongoing climate change. Testate amoebae are useful bioindicators of hydrological changes, but little experimental work has been done on the impact of water table changes on communities. Using a mesocosm experimental setting that was previously used to assess the impact of...

Accès public à partir du 1 févr. 2019
Université de Neuchâtel

Taxonomic and functional traits responses of Sphagnum peatland testate amoebae to experimentally manipulated water table

Koenig, Isabelle ; Mulot, Matthieu, Laboratory of Soil Diversity, University of Neuchâtel, Switzerland ; Mitchell, Edward AD

In: Ecological Indicators, 2018, vol. 85, p. 342-351

Biomonitoring tools are useful to assess the impact of environmental changes on the functioning of ecosystems. Existing tools mostly require species identification, thus allowing to estimating changes in biodiversity, and possibly inferring ecosystem functioning, using functional diversity and traits based approaches. Testate amoebae are good indicators of surface moisture conditions in...

Université de Neuchâtel

Effect of taxonomic resolution on ecological and palaeoecological inference : a test using testate amoeba water table depth transfer functions

Mitchell, Edward A. D ; Lamentowicz, Mariusz ; Payne, Richard J ; Mazei, Yuri

In: Quaternary Science Reviews, 2014, vol. 91, p. 62-69

Sound taxonomy is a major requirement for quantitative environmental reconstruction using biological data. Transfer function performance should theoretically be expected to decrease with reduced taxonomic resolution. However for many groups of organisms taxonomy is imperfect and species level identification not always possible. We conducted numerical experiments on five testate amoeba water table...

Université de Neuchâtel

The Phanerozoic diversification of silica-cycling testate amoebae and its possible links to changes in terrestrial ecosystems

Lahr, Daniel J.G ; Bosak, Tanja ; Lara, Enrique ; Mitchell, Edward A.D

In: PeerJ, 2015, vol. 3:e1234, p. 1-19

The terrestrial cycling of Si is thought to have a large influence on the terrestrial and marine primary production, as well as the coupled biogeochemical cycles of Si and C. Biomineralization of silica is widespread among terrestrial eukaryotes such as plants, soil diatoms, freshwater sponges, silicifying flagellates and testate amoebae. Two major groups of testate (shelled) amoebae, arcellinids...

Université de Neuchâtel

Environmental DNA COI barcoding for quantitative analysis of protists communities: A test using the Nebela collaris complex (Amoebozoa;Arcellinida; Hyalospheniidae)

Kosakyan, Anush ; Mulot, Matthieu ; Mitchell, Edward A.D ; Lara, Enrique

In: European Journal of Protistology, 2015, vol. 51, no. 4, p. 311-320

Environmental DNA surveys are used for screening eukaryotic diversity. However, it is unclear how quantitative this approach is and to what extent results from environmental DNA studies can be used for ecological studies requiring quantitative data. Mitochondrial cytochrome oxidase (COI) is used for species-level taxonomic studies of testate amoebae and should allow assessing the community...

Université de Neuchâtel

Comparative ecology of vascular plant, bryophyte and testate amoeba communities in four Sphagnum peatlands along an altitudinal gradient in Switzerland

Koenig, Isabelle ; Feldmeyer-Christe, Elizabeth ; Mitchell, Edward AD

In: Ecological Indicators, 2015, vol. 54, p. 48-59

Monitoring tools are needed to assess changes in peatland biotic communities and ecosystem functions in response to on-going climate and other environmental changes. Although the responses of soil organisms and plants to ecological gradients and perturbations do not always correlate, peatland monitoring is mainly based on vegetation surveys. Testate amoebae, a group of protists, are important...

Université de Neuchâtel

Can soil testate amoebae be used for estimating the time since death? : A field experiment in a deciduous forest

Szelecz, Ildikò ; Fournier, Bertrand ; Seppey, Christophe ; Amendt, Jens ; Mitchell, Edward

In: Forensic Science International, 2014, vol. 236, p. 90-98

Estimation of the post-mortem interval (PMI, the time interval between death and recovery of a body) can be crucial in solving criminal cases. Today minimum PMI calculations rely mainly on medical and entomological evidence. However, beyond 4–6 weeks even entomological methods become less accurate. Thus additional tools are needed. Cadaveric fluids released by decomposing cadavers modify the...

Université de Neuchâtel

Toward the use of testate amoeba functional traits as indicator of floodplain restoration success

Fournier, Bertrand ; Malysheva, Elena ; Mazei, Yuri ; Moretti, Marco ; Mitchell, Edward A.D.

In: European Journal of Soil Biology, 2012, vol. 49, p. 85-91

Functional traits (FT) offer a new framework to understand the ecology of organisms and overcome taxonomic difficulties that currently limit the study of minute soil taxa. FT are likely to be selected by environmental filters and hence they may provide more direct information on ecosystem characteristics than the species composition of a community. We tested the potential of testate amoeba...

Université de Neuchâtel

Molecular phylogeny and taxonomy of Testate amoebae (protist) and host-symbiont evolutionary relationships within mixotrophic taxa

Gomaa, Fatma ; Mitchell, Edward (Dir.) ; Lara, Enrique (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2012.

Les recherches en phylogénie moléculaire ont considérablement avancé notre compréhension des relations entre eucaryotes. Les classifications récentes placent les protistes amoeboides dans plus de 30 lignées au sein des Amoebozoa, Rhizaria, Stramenopiles, Opisthokonta, et Excavata. Parmi celles-ci, certaines branches ont développé des thèques ou coquilles, souvent ornementées et...