title: Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium.
abstract: Testate amoebae are free-living shelled protists that build a wide range of shells with various sizes, shapes, and compositions. Recent studies showed that xenosomic testate amoebae shells could be indicators of atmospheric particulate matter (PM) deposition. However, no study has yet been conducted to assess the intra-specific mineral, organic, and biologic grain diversity of a single xenosomic species in a natural undisturbed environment. This study aims at providing new information about grain selection to develop the potential use of xenosomic testate amoebae shells as bioindicators of the multiple-origin mineral/organic diversity of their proximal environment. To fulfil these objectives, we analysed the shell content of 38 Bullinularia indica individuals, a single xenosomic testate amoeba species living in Sphagnum capillifolium, by scanning electron microscope (SEM) coupled with X-ray spectroscopy. The shells exhibited high diversities of mineral, organic, and biomineral grains, which confirms their capability to recycle xenosomes. Mineral grain diversity and size of B. indica matched those of the atmospheric natural mineral PM deposited in the peatbog. Calculation of grain size sorting revealed a discrete selection of grains agglutinated by B. indica. These results are a first step towards understanding the mechanisms of particle selection by xenosomic testate amoebae in natural conditions.
authors.affiliation: Laboratoire Chrono-Environnement, UMR 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030 Besançon Cedex, France; Université de Lille, UMR LOG 8187 CNRS, ULCO Laboratoire d'Océanologie et Géosciences, Bâtiment SN5, 59655 Villeneuve-d'Ascq, France. Electronic address: maxence.delaine@gmx.fr.
authors.forename: Maxence
authors.initials: M
authors.lastname: Delaine
authors.affiliation: Laboratoire Chrono-Environnement, UMR 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030 Besançon Cedex, France; Laboratoire THéMA, UMR 6049, CNRS, Université de Bourgogne Franche-Comté, 32 rue Mégevand, 25030 Besançon Cedex, France.
authors.forename: Nadine
authors.initials: N
authors.lastname: Bernard
authors.affiliation: Laboratoire Chrono-Environnement, UMR 6249, Université de Bourgogne Franche-Comté, 16 route de Gray, 25030 Besançon Cedex, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gilbert
authors.affiliation: Université de Lille, UMR LOG 8187 CNRS, ULCO Laboratoire d'Océanologie et Géosciences, Bâtiment SN5, 59655 Villeneuve-d'Ascq, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Recourt
authors.affiliation: Université de Lille, UMR LOG 8187 CNRS, ULCO Laboratoire d'Océanologie et Géosciences, Bâtiment SN5, 59655 Villeneuve-d'Ascq, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Armynot du Châtelet
mesh_terms: D016840:Lobosea / Q000737:chemistry* / Q000145:classification* / Q000502:physiology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D013052:Spectrometry, X-Ray Emission; D044003:Sphagnopsida / Q000469:parasitology*
keywords: Arcellinida; Atmospheric particle deposits; Bioindicators; Shell composition; Sphagnum peatbog; Testate amoebae