Publications by authors named "Michel Lafont"

The genus belongs to the subfamily Naidinae (Naididae); it includes mostly species of small size and is diverse and abundant in surface coarse sediments in streams. The aim of the present study is to initiate an inventory of lineages (=species) of in Switzerland. We used 135 specimens collected at 6 sites in 4 streams of 4 cantons.

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Implemented for decades as part of the 'best management practices (BMPs)' for controlling urban runoff impacts on receiving waters, stormwater management ponds (SMPs) have been increasingly viewed as potential habitats for urban wildlife. However, since SMPs are subject to a lot of environmental constraints, research toward assessing their ecological quality and their actual benefits as habitats for biota is needed. In this study, the sediment toxicity of eight SMPs located in Southern Ontario, Canada was assessed using the sediment quality triad (SQT) approach.

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The effects of regional (hydrogeology and geomorphology) and local (sediment and hydrology) characteristics on hyporheic assemblages were studied along a 40-km reach of a large gravel-bed river. Hyporheic water and fauna were sampled at the upstream and downstream positions of 15 large gravel bars. The resulting 30 stations varied in their sediment grain size, stability and direction of river-aquifer exchanges.

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The presence of the oligochaete species (Smith, 1900) originating from North America has been mentioned for several decades in Europe, the Middle East and Russia. Its distribution and abundance in Europe is still unknown but it can be considered as potentially invasive. This species was recently discovered in Lake Geneva (Switzerland/France) and three other Swiss lakes.

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Aquatic oligochaete communities are valuable indicators of the biological quality of sediments in streams and lakes, but identification of specimens to the species level based on morphological features requires solid expertise in taxonomy and is possible only for a fraction of specimens present in a sample. The identification of aquatic oligochaetes using DNA barcodes would facilitate their use in biomonitoring and allow a wider use of this taxonomic group for ecological diagnoses. Previous approaches based on DNA metabarcoding of samples composed of total sediments or pools of specimens have been proposed for assessing the biological quality of ecosystems, but such methods do not provide precise information on species abundance, which limits the value of resulting ecological diagnoses.

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Introduction: Aquatic oligochaetes represent valuable indicators of the quality of sediments of watercourses and lakes, but their difficult identification based on morphological criteria compromises their more common use for eco-diagnostic analyses. This issue could be overcome by using DNA barcodes for species identification. A 10% threshold of cytochrome c oxidase (COI) divergence was proposed for differentiating between oligochaete species based on molecular and morphological data.

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Aquatic oligochaetes are well recognized bioindicators of quality of sediments and water in watercourses and lakes. However, the difficult taxonomic determination based on morphological features compromises their more common use in eco-diagnostic analyses. To overcome this limitation, we investigated molecular barcodes as identification tool for broad range of taxa of aquatic oligochaetes.

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Stormwater ponds have been widely used to control increased surface runoff resulting from urbanization, and to enhance runoff quality. As receiving waters, they are impacted by intermittent stormwater pollution while also serving as newly created aquatic habitats, which partly offset changes of aquatic ecosystems and their biodiversity by urbanization. Thus, determining ecological risks in stormwater ponds is important for the preservation and rehabilitation of biodiversity in urban areas.

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In soft-bottom sediments, consumers may influence ecosystem function more via engineering that alters abiotic resources than through trophic influences. Understanding the influence of bioturbation on physical, chemical, and biological processes of the water-sediment interface requires investigating top-down (consumer) and bottom-up (resource) forces. The objective of the present study was to determine how consumer bioturbation mode and sediment properties interact to dictate the hydrologic function of experimental filtration systems clogged by the deposition of fine sediments.

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The purpose of this study was to quantify the influences of tubificid worms on the biogeochemical functioning of an infiltration system impacted by a stormwater sediment deposit. Effects of worms with stormwater sediment deposit were compared with effects of worms with two other natural sediment deposits (one low and one rich-particulate organic matter deposits). We measured the effects of invertebrates on sediment reworking, organic matter processing, solute fluxes, microbial characteristics, and pollutant release from stormwater deposit to water.

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This paper provides original collection, acclimatizing, rearing and toxicity test methods for the freshwater worm Branchiura sowerbyi, an alternative species to Tubifex tubifex for ecotoxicity evaluation of sediments. Influence of the substrate, type of food, and feeding level on individual performances was assessed in short-term tests, in order to set up optimal culture and test conditions. Low-size particles and high organic matter content favoured the growth and reproduction of B.

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An original species-selection method for the building of test batteries is presented. This method is based on the statistical analysis of the biological and ecological trait patterns of species. It has been applied to build a macroinvertebrate test battery for the assessment of sediment toxicity, which efficiently describes the diversity of benthic macroinvertebrate biological responses to toxicants in a large European lowland river.

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