scholarly journals Microplastic and Fibre Contamination in a Remote Mountain Lake in Switzerland

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2410
Author(s):  
Angel de Jesús Negrete Velasco ◽  
Lionel Rard ◽  
Wilfried Blois ◽  
David Lebrun ◽  
Franck Lebrun ◽  
...  
Keyword(s):  
Water Column ◽  
Chemical Nature ◽  
Optical Microscope ◽  
Mountain Lake ◽  
Aquatic Environments ◽  
Digestion Process ◽  
Rivers And Lakes ◽  
Remote Environment ◽  
Aerial Deposition

The contamination of aquatic environments by microplastics has been largely documented in the last years, especially in oceans, rivers, and lakes, but their occurrence in remote mountain lakes has been scarcely considered. This work aims to investigate the presence and abundance of microplastics and fibres in a remote, alpine, and uninhabited lake in Switzerland (Sassolo). In this study, the water column as well as the sediments were analysed. The isolation of microplastics and fibres from the samples of the sediment was achieved with a digestion process using H2O2 and a density separation technique with NaI. Classification of microparticles (from 5 mm to 125 μm) was first developed with an optical microscope. Infrared spectroscopy was then used to identify and characterize the chemical nature of the microplastics and fibres. On average, 2.6 microplastics and 4.4 fibres per litre were identified in the water column. On the other hand, the results of the sediment samples revealed significant fibre concentrations compared to plastic microparticles (514 fibres and 33 microplastics per kilogram). The most abundant types of microplastic identified in the samples were composed of polyethylene (PE) and polypropylene (PP). Microplastic and fibre sources were not determined, but it is likely that the number of human activities in this area as well as aerial deposition are contributing to contaminate this remote environment with microplastics and fibres.

The Chemistry Of Antibiofilm Phytocompounds.

2020 ◽  
Vol 20 ◽  
Author(s):  
Dibyajit Lahiri ◽  
Moupriya Nag ◽  
Sayantani Garai ◽  
Rina Rani Ray
Keyword(s):  
Antimicrobial Activity ◽  
Antibiotic Resistance ◽  
Antibiotic Therapy ◽  
Antimicrobial Agents ◽  
Chemical Nature ◽  
Rapid Development ◽  
Wide Spread ◽  
Chronic Infections ◽  
Therapeutic Uses

: Phytocompounds are long known for their therapeutic uses due to their competence as antimicrobial agents. The antimicrobial activity of these bioactive compounds manifests their ability as an antibiofilm agent and is thereby proved to be competent to treat the wide spread of biofilm-associated chronic infections. Rapid development of antibiotic resistance in bacteria has made the treatment of these infections almost impossible by conventional antibiotic therapy, which forced in the switch over to the use of phytocompounds. The present overview deals with the classification of the huge array of phytocompounds according to their chemical nature, detection of their target pathogen, and elucidation of their mode of action.

scholarly journals Biogeochemical and microbial seasonal dynamics between water column and sediment processes in a productive mountain lake: Georgetown Lake, MT, USA

2016 ◽  
Vol 121 (8) ◽  
pp. 2064-2081 ◽  
Author(s):  
Stephen R. Parker ◽  
Robert F. West ◽  
Eric S. Boyd ◽  
Jayme Feyhl-Buska ◽  
Christopher H. Gammons ◽  
...  
Keyword(s):  
Water Column ◽  
Seasonal Dynamics ◽  
Mountain Lake

scholarly journals Gastronomic Metaphor in the Russian Pre-Revolutionary Parliamentary Discourse (based on Speeches by Right-Wing Deputies)

2020 ◽  
pp. 25-37 ◽  
Author(s):  
S. A. Gromyko
Keyword(s):  
Political Activity ◽  
Right Wing ◽  
Political Struggle ◽  
Digestion Process ◽  
Negative Appraisal ◽  
Quality Of Food ◽  
Semantic Aspect ◽  
Food Consumed

The results of a study of the semantics and functioning of the gastronomic metaphor in the Russian parliamentary discourse are presented in the article. Based on the material of the parliamentary discussion of the early twentieth century, the features of the functioning of metaphors, which are based on the associative similarity between political activity and food, the eating process are established. The author dwells in detail on the use of gastronomic metaphors by nationalist deputies in the course of discussions unfolding at meetings of the State Duma. The results of the classification of metaphors identified on the indicated material belonging to the “Food” sphere are presented. It was established that they can be divided into three groups according to the figurative component: metaphors with the literal meaning of absorbing or eating something, metaphors with the value of the quality of food consumed, metaphors with the value of the digestion process. It is concluded that in the semantic aspect, the gastronomic metaphor in the Russian parliamentary discourse expresses a persistent negative assessment, since it is associated with the semantics of extermination, destruction, deception ( to give a stone instead of bread ), abnormal physiological phenomena (hunger, overeating, indigestion). It is emphasized that in the functional aspect, the negative appraisal of the gastronomic metaphor made it possible to use it in parliamentary discourse as a means of political struggle with the aim of lowering the political assets of opponents.

Environmental Fate of Polychlorinated Dibenzo-p-dioxins in Lake Enclosures

1992 ◽  
Vol 49 (4) ◽  
pp. 722-734 ◽  
Author(s):  
Mark R. Servos ◽  
Derek C. G. Muir ◽  
G. R. Barrie Webster
Keyword(s):  
Organic Matter ◽  
Water Column ◽  
Particulate Organic Matter ◽  
Environmental Fate ◽  
Aquatic Environments ◽  
Surficial Sediments ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Chlorine Substitution ◽  
Sediment Slurry

The environmental fate of 1,3,6,8-tetra- (T4CDD) and octachlorodibenzo-p-dioxin (O8CDD), two major dioxin congeners emitted into the environment, was studied in large (40 m3) lake enclosures at the Experimental Lakes Area in northwestern Ontario. The polychlorinated dioxins (PCDDs) were added to replicate enclosures as a sediment slurry at a nominal concentration of 58–59 ng∙L−1. Both congeners partitioned/settled rapidly to the surficial sediments where they persisted over the 2 yr of the study. Initially the concentrations of the T4CDD in water were higher than those of O8CDD, but the concentrations of the T4CDD in the water column declined more rapidly than those of O8CDD, with t1/2 of 2.6 ± 0.2 and 4.0 ± 0.3 d, respectively. Approximately 10–15% of the T4CDD and < 1% of the O8CDD detected in the water column during the first 48 h were determined to be truly dissolved. The rapid partitioning of O8CDD and to a lesser extent T4CDD to dissolved and particulate organic matter in the water column and sediments limited their bioavailability. Increased retentive capacity of the higher chlorinated PCDDs may explain the pattern of increasing concentration of PCDDs in sediments with increasing chlorine substitution observed in the Great Lakes and other aquatic environments.

scholarly journals Mimiviridae: An Expanding Family of Highly Diverse Large dsDNA Viruses Infecting a Wide Phylogenetic Range of Aquatic Eukaryotes

Viruses ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 506 ◽  
Author(s):  
Jean-Michel Claverie ◽  
Chantal Abergel
Keyword(s):  
Historical Review ◽  
Aquatic Environments ◽  
Taxonomic Structure ◽  
Dna Virus ◽  
Chlorella Virus ◽  
Genome Complexity ◽  
Algal Viruses ◽  
Operational Criteria ◽  
Dsdna Viruses

Since 1998, when Jim van Etten’s team initiated its characterization, Paramecium bursaria Chlorella virus 1 (PBCV-1) had been the largest known DNA virus, both in terms of particle size and genome complexity. In 2003, the Acanthamoeba-infecting Mimivirus unexpectedly superseded PBCV-1, opening the era of giant viruses, i.e., with virions large enough to be visible by light microscopy and genomes encoding more proteins than many bacteria. During the following 15 years, the isolation of many Mimivirus relatives has made Mimiviridae one of the largest and most diverse families of eukaryotic viruses, most of which have been isolated from aquatic environments. Metagenomic studies of various ecosystems (including soils) suggest that many more remain to be isolated. As Mimiviridae members are found to infect an increasing range of phytoplankton species, their taxonomic position compared to the traditional Phycodnaviridae (i.e., etymologically “algal viruses”) became a source of confusion in the literature. Following a quick historical review of the key discoveries that established the Mimiviridae family, we describe its current taxonomic structure and propose a set of operational criteria to help in the classification of future isolates.

scholarly journals Automated classification of schools of the silver cyprinid Rastrineobola argentea in Lake Victoria acoustic survey data using random forests

2020 ◽  
Vol 77 (4) ◽  
pp. 1379-1390 ◽  
Author(s):  
Roland Proud ◽  
Richard Mangeni-Sande ◽  
Robert J Kayanda ◽  
Martin J Cox ◽  
Chrisphine Nyamweya ◽  
...  
Keyword(s):  
Time Series ◽  
Water Column ◽  
Random Forests ◽  
Lake Victoria ◽  
Test Accuracy ◽  
Acoustic Survey ◽  
Automated Classification ◽  
School Based ◽  
Schooling Fish

Abstract Biomass of the schooling fish Rastrineobola argentea (dagaa) is presently estimated in Lake Victoria by acoustic survey following the simple “rule” that dagaa is the source of most echo energy returned from the top third of the water column. Dagaa have, however, been caught in the bottom two-thirds, and other species occur towards the surface: a more robust discrimination technique is required. We explored the utility of a school-based random forest (RF) classifier applied to 120 kHz data from a lake-wide survey. Dagaa schools were first identified manually using expert opinion informed by fishing. These schools contained a lake-wide biomass of 0.68 million tonnes (MT). Only 43.4% of identified dagaa schools occurred in the top third of the water column, and 37.3% of all schools in the bottom two-thirds were classified as dagaa. School metrics (e.g. length, echo energy) for 49 081 manually classified dagaa and non-dagaa schools were used to build an RF school classifier. The best RF model had a classification test accuracy of 85.4%, driven largely by school length, and yielded a biomass of 0.71 MT, only c. 4% different from the manual estimate. The RF classifier offers an efficient method to generate a consistent dagaa biomass time series.

The redox speciation of iron in two lakes

2001 ◽  
Vol 52 (6) ◽  
pp. 885 ◽  
Author(s):  
Annette P. Aldrich ◽  
Constant M. G. van den Berg ◽  
Hansjörg Thies ◽  
Ulrike Nickus
Keyword(s):  
Water Column ◽  
Ice Cover ◽  
Open Ocean ◽  
Mountain Lake ◽  
Chl A ◽  
Reactive Iron ◽  
Lake Waters ◽  
Redox Speciation ◽  
Iron Concentrations

The redox speciation of iron was determined by voltammetry in two lakes (Blelham Tarn, a lowland lake, and Gossenk&ouml;llesee (GKS), a mountain lake). The reactive iron (FeR) concentration was ~40 nM in the epilimnion of Blelham Tarn, and up to 37% of this occurred as iron(II). In contrast, the FeR concentration in GKS was much lower at ~1 nM, similar to concentrations found in the open ocean. Under ice cover the iron(II) concentration peaked in GKS just below the Chl-a maximum, amounting to 50% of FeR. In July, the Chl-a concentration was lower, and iron(II) was present throughout the water column at ~30% of FeR. This work has demonstrated that iron occurs to a large extent as iron(II) in lake waters, of greatly differing conditions, in spite of the presence of oxygen; the main cause for this is not clear because the iron(II) may have been produced biologically or photochemically (or both). This, and the unexpectedly low reactive-iron concentrations in the transparent mountain-lake waters, warrant further work to evaluate their importance to the microorganisms in the lakes.

Research on the Controlled Ecological Risk of Reservoir Operation

2013 ◽  
Vol 742 ◽  
pp. 337-340
Author(s):  
Ting Gao ◽  
Ke Yang ◽  
Bin Wu ◽  
Lin Lin Zhang ◽  
Zi Chao Zhao ◽  
...  
Keyword(s):  
Risk Factors ◽  
Risk Assessment ◽  
Ecological Risk ◽  
Reservoir Operation ◽  
Ecological Risks ◽  
Water Network ◽  
Risk Transfer ◽  
Rivers And Lakes ◽  
Ecological Risk Factors

The lake rate and density of the water network the reservoir area generally increased after the impoundment of the reservoir, the original forest, farmland, villages were submerged, the water hydrographic characteristics was gradually changed from rivers to lakes - rivers and lakes type. In this context, this paper set out ecological risks caused by reservoir operation and planed ecological risk assessment works, summarized the classification of ecological risk factors and had the preliminary clarify in the risk transfer relationships.

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