Survivalisme | EPFL Graph Search

vignette|redresse=1|Couverture du , une publication officielle du gouvernement des États-Unis (Executive Office of the President, National Security Resources Board et Civil Defense Office) de 1950. Le survivalisme est un terme qui désigne les activités de certains individus ou groupes d'individus qui se préparent à une catastrophe éventuelle (catastrophe naturelle, crise économique, crise sanitaire, etc.) à l'échelle locale ou globale, voire à un événement potentiellement cataclysmique (effondrement écologique, guerre nucléaire, invasion extraterrestre, etc.), ou plus généralement à un effondrement de la civilisation industrielle. Les survivalistes se préparent en modifiant leurs habitations, en apprenant des techniques de survie et des rudiments de notions médicales, en stockant de la nourriture et des armes, en construisant des abris antiatomiques, ou en apprenant certaines techniques de bushcraft afin de s'abriter, se réchauffer, avoir de l'eau potable et se nourrir en milieu sauv

Treatment of micropollutants in municipal wastewater using white-rot fungi

David Andrew Barry, Andreu Contijoch Culleré, Christof Holliger, Jonas Margot

Treatment of micropollutants such as pharmaceuticals and pesticides in municipal wastewater is challenging due to their very low concentrations (ng/l to µg/l), their relatively low biodegradability, and their different physico-chemical characteristics. One potential way to improve micropollutant biodegradation in wastewater treatment plant (WWTP) effluent is by using microorganisms such as white-rot fungi that produce powerful unspecific oxidative exo-enzymes (laccase, peroxidase) that are able to oxidize several micropollutants recalcitrant to bacterial degradation. The goals of this study were (i) to evaluate the ability of white-rot fungi to degrade pharmaceuticals and pesticides and (ii) to develop a fungal treatment which allows removal of a broad range of pollutants but also long-term survival of the fungus in the system. For the first objective, batch experiments with the white-rot fungus Trametes versicolor were conducted first in defined medium containing glucose and spiked with 10 mg/l of pollutant (naproxen, sulfamethoxazole or isoproturon), and then in real unsterile WWTP effluents (not spiked) with wheat straw as sole carbon and energy source. T. versicolor was able to remove over 90% of naproxen in less than 24 h, and sulfamethoxazole and isoproturon in less than 4 d in defined media spiked with these pollutants. In real unsterile biologically treated wastewater, T. versicolor could remove over 90% of the anti-inflammatory drugs diclofenac and mefenamic acid in less than 24 h, and naproxen in less than 48 h, despite their low concentrations (400-800 ng/l). These good removal rates were however not observed for other compounds that needed longer reaction times, due to the short survival (one week) of the fungus in unsterile wastewater. To increase the chance to maintain this organism in the treatment, we designed a fungal unsaturated biotrickling filter composed of wood chips colonized by the mycelium of the white-rot fungi T. versicolor or Pleurotus ostreatus. Unsterile tap water or treated wastewater spiked with pollutants (10 mg/l) were then trickled with recirculation through the wood-mycelium support. This system allowed a much better survival of the two fungi and was able to remove almost completely naproxen, diclofenac, mefenamic acid, paracetamol, bisphenol A, and triclosan in less than 8 h. Future experiments will show whether the oxidation potential of these fungal filters is applicable to a wider range of pollutants.

2014

Occurrence and ecological determinants of the contamination of floodplain wetlands with Klebsiella pneumoniae and pathogenic or antibiotic-resistant Escherichia coli

François Gillet

The survival and multiplication of human pathogenic and antibiotic-resistant bacteria in ecosystems is of increasing concern but has been little explored. Wetlands can be contaminated by water fluxes from rivers and may present environmental conditions leading to bacterial survival and multiplication. To test this hypothesis, we sampled 16 wetlands located along three rivers of the Jura Massif, France. The bacterial contamination of the wetland and river waters was measured monthly over a one-year cycle together with the water physico-chemical characteristics. We assessed the abundance of three pathogenic species: Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The concentrations of E. coli producing extended-spectrum beta-lactamase (ESBL E. coli) or belonging to the phylogenetic group B2 (E. coli B2-more pathogenic) were also measured. We found that rivers carried total E. coli, ESBL E. coli, and K. pneumoniae to wetlands. ESBL E. coli poorly survived in wetlands, whereas total E. coli and K. pneumoniae possibly met favourable physico-chemical conditions for survival and multiplication in these habitats. K. pneumoniae peaked in summer in warm and shallow wetlands. Total E. coli and E. coli B2 potentially reached wetlands through sources other than rivers (hillslope groundwater or leaching from contaminated fields).

Oxford University Press (OUP)2019

Nurse plants, tree saplings and grazing pressure: decreasing facilitation along a biotic environmental gradient

Charlotte Vandenberghe

Current conceptual models predict that an increase in stress shifts interactions between plants from competitive to facilitative; hence, facilitation is expected to gain in ecological importance with increasing stress. Little is known about how facilitative interactions between plants change with increasing biotic stress, such as that incurred by consumer pressure or herbivory (i.e. disturbance sensu Grime). In grazed ecosystems, the presence of unpalatable plants is reported to protect tree saplings against cattle grazing and enhance tree establishment. In accordance with current conceptual facilitation-stress models, we hypothesised a positive relationship between facilitation and grazing pressure. We tested this hypothesis in a Weld experiment in which tree saplings of four diVerent species (deciduous Fagus sylvatica, Acer pseudoplatanus and coniferous Abies alba, Picea abies) were planted either inside or outside of the canopy of the spiny nurse shrub Rosa rubiginosa in enclosures diVering in grazing pressure (low and high) and in exclosures. During one grazing season we followed the survival of the diVerent tree saplings and the level of browsing on these; we also estimated browsing damage to the nurse shrubs. Shrub damage was highest at the higher grazing pressure. Correspondingly, browsing increased and survival decreased in saplings located inside the canopy of the shrubs at the high grazing pressure compared to the low grazing pressure. Saplings of both deciduous species showed a higher survival than the evergreens, while sapling browsing did not diVer between species. The relative facilitation of sapling browsing and sapling survival – i.e. the diVerence between saplings inside and outside the shrub canopy – decreased at high grazing pressure as the facilitative species became less protective. Interestingly, these Wndings do not agree with current conceptual facilitationstress models predicting increasing facilitation with abiotic stress. We used our results to design a conceptual model of facilitation along a biotic environmental gradient. Empirical studies are needed to test the applicability of this model. In conclusion, we suggest that current conceptual facilitation models should at least consider the possibility of decreasing facilitation at high levels of stress.

2007