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Edward Mitchell

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Publications associées (72)

Species-specific effects of polyploidisation and plant traits of Centaurea maculosa and Senecio inaequidens on rhizosphere microorganisms

Alexandre Buttler, Edward Mitchell, Aurélie Thébault

Invasive plant species represent a threat to terrestrial ecosystems, but their effects on the soil biota and the mechanisms involved are not yet well understood. Many invasive species have undergone polyploidisation, leading to the coexistence of various c ...

Springer Verlag2010

Contrasting Species-Environment Relationships in Communities of Testate Amoebae, Bryophytes and Vascular Plants Along the Fen-Bog Gradient

Edward Mitchell, Mariusz Lamentowicz

We studied the vegetation, testate amoebae and abiotic variables (depth of the water table, pH, electrical conductivity, Ca and Mg concentrations of water extracted from mosses) along the bog to extremely rich fen gradient in sub-alpine peatlands of the Up ...

Springer-Verlag2010

Response of testate amoeba assemblages to environmental and climatic changes during the Lateglacial-Holocene transition at Lake Lautrey (Jura Mountains, eastern France)

Edward Mitchell

We tested the response of lacustrine testate amoebae (thecamoebians) to climate and environmental changes for the Lateglacial-Holocene transition. The palaeoenvironmental history of the study site (Lake Lautrey, Jura Mountains, eastern France) was previous ...

2010

Molecular phylogeny of euglyphid testate amoebae (Cercozoa: Euglyphida) suggests transitions between marine supralittoral and freshwater/terrestrial environments are infrequent

Enrique Lara, Edward Mitchell, Thierry Jean Heger

Marine and freshwater ecosystems are fundamentally different regarding many biotic and abiotic parameters. The physiological adaptations required for an organism to pass the salinity barrier are considerable. Many eukaryotic lineages are restricted to eith ...

Elsevier2010

A near-annual palaeohydrological study based on testate amoebae from a sub-alpine mire: surface wetness and the role of climate during the instrumental period

Edward Mitchell, Mariusz Lamentowicz

We present the first testate amoeba-based palaeohydrological reconstruction from the Swiss Alps, and the first depth to the water table (DWT) calibration data-set for this region. Compared to existing models, our new calibration data set performs well (RMS ...

2010

Testate Amoebae and Nutrient Cycling with Particular Reference to Soils

Edward Mitchell

We asked the following question: Is the lack of attention given to testate amoebae, and other protists, in studies of nutrient cycling justified by their relative unimportance or are we ignoring key players in nutrient cycling and other ecological processe ...

2010

Community development along a proglacial chronosequence: are above-ground and below-ground community structure controlled more by biotic than abiotic factors?

François Gillet, Edward Mitchell

P>1. We studied vascular plant and soil-dwelling testate amoeba communities in deglaciated sites across a range of substrate ages in Kenai Fjords, Alaska, USA to test four hypotheses. (i) Patterns of community assembly are similar for vascular plants and t ...

Wiley-Blackwell2010

Testate amoeba analysis of lake sediments: impact of filter size and total count on estimates of density, species richness and assemblage structure

Edward Mitchell

Testate amoebae are informative about palaeoecological conditions, but the methods generally used for their analyses in lake sediments differ from those used for their analyses in peats, making comparisons difficult. This study examines how filter mesh siz ...

2010

Effects of climatic change and bog development on Holocene tufa formation in the Lorze Valley (central Switzerland)

Edward Mitchell

A massive tufa complex in the lower Lorze Valley ( 550 m a.s.l., north-central Switzerland) formed between 9000 and 5000 cal. yr BP. In the plain 4 km southeast of the complex lies Neugrundmoor ( 830 m a.s.l.), a mire in the hydrologic recharge area of the ...

2010

The curse of taxonomic uncertainty in biogeographical studies of free-living terrestrial protists: a case study of testate amoebae from Amsterdam Island

Edward Mitchell, Thierry Jean Heger

Aim A current debate in microbial biogeography contrasts two views concerning the distribution of free-living microorganisms. The first view assumes a ubiquitous distribution, while the second view assumes that at least some species have limited geographic ...

2009

Morphology, Biometry, and Taxonomy of Freshwater and Marine Interstitial Cyphoderia (Cercozoa: Euglyphida)

Edward Mitchell, Thierry Jean Heger

Good taxonomy is essential for ecological, biogeographical, and evolutionary studies of any group of organisms. Therefore, we performed detailed light- and scanning electron microscopy (SEM) investigations on the shell ultrastructure and biometric analyses ...

2009

Cutover peatland regeneration assessment using organic matter and microbial indicators (bacteria and testate amoebae)

Alexandre Buttler, Edward Mitchell

Cutover peatlands cover large surfaces of high potential value for biodiversity and carbon sequestration function if successfully restored but the evaluation of restoration success is not straighforward. We assessed the bioindicator value of organic mat ...

2008

Autogenic succession, land-use change, and climatic influences on the Holocene development of a kettle hole mire in Northern Poland

Edward Mitchell, Mariusz Lamentowicz

We reconstructed the Holocene developmental history of a kettle-hole peatland in the Tuchola forest of Northern Poland, using pollen, testate amoebae and plant macrofossils indicators. Our aims were to determine the timing and pattern of autogenic successi ...

2008

Last millennium palaeoenvironmental changes from a Baltic bog (Poland) inferred from stable isotopes, pollen, plant macrofossils and testate amoebae

Edward Mitchell, Mariusz Lamentowicz

The Baltic coast of Northern Poland is a region of considerable potential interest for paleoclimatic studies because this region is under the influence of both oceanic and continental climates and that these two influences have likely changed through time. ...

2008

Functional microbial diversity in regenerating cutover peatlands responds to vegetation succession

Alexandre Buttler, Andy Siegenthaler, Edward Mitchell

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 availabili ...

2008

Potential implications of differential preservation of testate amoebae shells for paleoenvironmental reconstruction in peatlands

Edward Mitchell, Mariusz Lamentowicz

Testate amoebae are now commonly used in paleoenvironmental studies but little is known of their taphonomy. There is some experimental evidence for differential preservation of some testate amoeba shell types over others, but it is unclear what, if any imp ...

Springer Netherlands2008

Ribosomal RNA Genes Challenge the Monophyly of the Hyalospheniidae (Amoebozoa: Arcellinida)

Enrique Lara, Edward Mitchell, Thierry Jean Heger, Mariusz Lamentowicz

To date only five partial and two complete SSU rRNA gene sequences are available for the lobose testate amoebae (Arcellinida). Consequently, the phylogenetic relationships among taxa and the definition of species are still largely dependant on morphologica ...

2008

Testate amoebae analysis in ecological and paleoecological studies of wetlands: past, present and future

Edward Mitchell

Testate amoebae are an abundant and diverse polyphyletic group of shelled protozoa living in aquatic to moist habitats ranging from estuaries to lakes, rivers, wetlands, soils, litter, and moss habitats. Owing to the preservation of shells in sediments, te ...

Springer Netherlands2008

Effect of Lead Pollution on Testate Amoebae Communities living in Sphagnum fallax: an experimental study

Edward Mitchell

We studied the effects of lead pollution on testate amoebae communities living on Sphagnum fallax by growing this moss under controlled conditions. A progressive series of lead (Pb) concentration was used in the growing solution of the mosses: 0 (control), ...

2008

Effects of experimental lead pollution on the microbial communities associated to Sphagnum fallax (Bryophyta)

Edward Mitchell

Ecotoxicological studies usually focus on single microbial species under controlled conditions. As a result, little is known about the responses of different microbial functional groups or individual species to stresses. In an aim to assess the response of ...

2007

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