Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium

Delaine, Maxence; Bernard, Nadine; Gilbert, Daniel; Récourt, Philippe; Châtelet, Éric

doi:10.1016/j.ejop.2017.03.002

Cited by 4 publications

(3 citation statements)

References 33 publications

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“…The existing monographs on individual genera, mostly describe the larger taxa (Chardez, 1969(Chardez, , 1985Decloître, 1962;Deflandre, 1928;Deflandre, 1929;Deflandre, 1936;Grospietsch, 1958;Thomas and Gauthier-Lièvre, 1959), except for genera Cryptodifflugia and Difflugiella (Page 1966;Grospietsch 1965). By contrast, knowledge on the diversity of agglutinated xenosomic species is limited (Delaine et al, 2017), making these taxa (such as Phryganella paradoxa, Pseudodifflugia fulva, Difflugia pulex and Difflugia pristis) particularly challenging to identify and differentiate. As a result, they are often lumped by community analysts, leaving their value as bioindicators poorly defined.…”

Section: Introductionmentioning

confidence: 99%

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

McKeown

Wilmshurst

Duckert

et al. 2019

European Journal of Protistology

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Methodological advances are essential for robust ecological research. Quantitative reconstructions of environmental conditions using testate amoebae rely on sound taxonomy. While the taxonomy of large species is relatively well resolved, this is not the case for most small taxa (typically <45 m long). In New Zealand, peatlands contain a diversity of both cosmopolitan and characteristic large southern endemic taxa, but also have a high abundance of small taxa. The latter are often lumped into morphotypes reducing their value as ecological indicators. In this study, we demonstrate how (a) lumping small taxa versus splitting them into unique types, and (b) including or excluding them from community analysis influenced their ecological inference. We assessed testate amoeba composition in six peat bogs from New Zealand, three that were moderately-to-highly impacted, and three that were non-impacted. Environmental variables were measured at each sampling site and the surface testate amoeba community patterns and community-environment relationships compared. We found a clear division between impacted and non-impacted sites. Several distinct small taxa were more strongly related to water-table depth and conductivity, while the larger taxa were more correlated to pH. These results show that improved taxonomic resolution of small taxa can provide more informed environmental assessment.

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Section: Introductionmentioning

confidence: 99%

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

McKeown

Wilmshurst

Duckert

et al. 2019

European Journal of Protistology

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“…Their environments are widespread on earth and include soils, bogs, mosses, rivers, lakes, and ponds. − These species have been of keen interest to ecologists, soil scientists, and paleontologists since the 19th century and have gained increased importance as a study group over the past two decades . More than 300 species and 200 subspecies, varieties, or forms have been described as belonging to the genus Difflugia (Leclerc, 1815), − and it has been suggested that taxon richness has been considerably underestimated. − The taxonomy of this genus has historically been based on differences in shape, size, and mineral composition of the thecae as determined primarily by light microscopy; however, recent studies involving molecular (DNA) analysis have suggested a greater complexity than what is revealed by shell composition and morphology and that both phenotypic plasticity and cryptic diversity are significant. − Shell morphology and composition can be related to growth location, the external environment, and in particular, the building materials available in those environments. − …”

Section: Introductionmentioning

confidence: 99%

Amoebae Assemble Synthetic Spherical Particles To Form Reproducible Constructs

et al. 2019

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Dif f lugia are testate amoebae that use particulate inorganic matter to build a protective shell (generally called a test or theca). Difflugia globulosa were grown both in culture containing only naturally occurring theca-building materials and under conditions where synthetic particles were present also. The presence of monodisperse Stober silica microspheres of 1, 3, and 6 μm in diameter or 4 μm polystyrene spheres dramatically increased the rate of Diff lugia growth, and foreign microspheres became the overwhelmingly dominant construction material. Optical and electron microscopy of the 6 μm particle studies revealed that Diff lugia construct spherical vase-shaped thecae with strikingly reproducible composition, morphology, and size. Timelapse photography revealed construction techniques and masonry skills as Diff lugia herded particles together, trapped them using phagocytosis, and applied the particles with biocement from inside the developing theca. The reported observations identify taxonomy complications, biomicrofabrication possibilities, and a discrete environmental impact of synthetic particle pollutants.

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“…Tests are made of self-secreted protein, self-secreted silica plates (idiosomes) or an agglutination (xenosomes) of either prey (diatom frustules, euglyphid plates, i.e. kleptoplastidy - Lahr et al 2015) or mineral particles present locally (Ogden and Hedley 1980;Delaine et al 2017). Testate amoebae are a dominant group of micro-organisms in wet and humid environments (Gilbert et al 1998;Gilbert and Mitchell 2006) and play a central role in soil microbial food webs and C cycling in Sphagnum peatlands (Wilkinson and Mitchell 2010;Jassey et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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

Schwendener

Mulot

et al. 2017

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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 drought disturbance on communities and ecosystem processes with three contrasted water table positions: wet (-4 cm), intermediate (-15 cm) and dry (-25 cm), we studied the capacity of testate amoeba communities to recover when the water table was kept at-10 cm for all plots. The overall experiment lasted three years. We assessed the taxonomic and functional trait responses of testate amoeba communities. The selected traits were hypothesised to be correlated to moisture content (response traits: shell size, aperture position) or trophic role (effect traits: mixotrophy, aperture size controlling prey range). During the disturbance phase, the mixotrophic species Hyalosphenia papilio dominated the wet and intermediate plots, while the community shifted to a dominance of "dry indicators" (Corythion dubium, Nebela tincta, Cryptodifflugia oviformis) and corresponding traits (loss of mixotrophy, and dominance of smaller taxa with ventral or ventral-central aperture) in dry plots. During the recovery phase we observed two contrasted trends in the previously wet and intermediate plots: communities remained similar where the Sphagnum carpet remained intact but species and traits indicators of drier conditions increased in plots where it had degraded. In the former dry plots, indicators and traits of wet conditions increased by the end of the experiment. This is one of the first experiment simulating a disturbance and subsequent recovery in ex-situ mesocosms of Sphagnum peatland focusing on the response of testate amoebae community structure as well as functional traits to water table manipulation. The results generally confirmed that testate amoebae respond within a few months to hydrological changes and thus represent useful bioindicators for assessing current and past hydrological changes in Sphagnum peatlands.

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Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium

Cited by 4 publications

References 33 publications

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

Amoebae Assemble Synthetic Spherical Particles To Form Reproducible Constructs

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

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Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium

Cited by 4 publications

References 33 publications

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

Amoebae Assemble Synthetic Spherical Particles To Form Reproducible Constructs

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

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Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands

Assessing the ecological value of small testate amoebae (<45 μm) in New Zealand peatlands