Search results for "Sediment"

Meromixis origin and recent trophic evolution in the Spanish mountain lake La Cruz

1998

A sediment core from a Mediterranean karstic lake was studied through its pollen, diatom, chydorid, ostracod, charcoal and authigenic mineral composition. Information about environmental history recorded in the sediment sequence since the Middle Ages is presented. The main fluctuations of water volume and trophic status of the lake occurred during periods of great change in land management and during climatic cold phases. The synergetic effect of these two factors led to a high water level phase and triggered a rising of the trophic level which produced meromixis. The onset of meromictic conditions at about 1700 AD coincides with the Maunder minimum in the Little Ice Age as well as with a p…

Assessing the land cover and land use change and its impact on watershed services in a tropical Andean watershed of Peru

2009

Satamasedimenttien ekotoksikologinen riskinarviointi

2008

Partitioning of nanoparticle-originated dissolved silver in natural and artificial sediments

2017

Sediments are believed to be a major sink for silver nanoparticles (AgNPs) in the aquatic environment, but there is a lack of knowledge about the environmental effects and behavior of AgNPs in sediments. The release of highly toxic Ag+ through dissolution of AgNPs is one mechanism leading to toxic effects in sediments. We applied an ultrasound-assisted sequential extraction method to evaluate the dissolution of AgNPs and to study the partitioning of dissolved Ag in sediments. Silver was spiked into artificial and 2 natural sediments (Lake Höytiäinen sediment and Lake Kuorinka sediment) as silver nitrate (AgNO3), uncoated AgNPs, or polyvinylpyrrolidone-coated AgNPs (PVP-AgNPs). In addition, …

Recovery of Historically Contaminated Watercourse Polluted by the Chemical Wood Industry: EROD Activity in Fish as Biomarker

2013

Despite outstanding process alterations over decades, pulp- and paper-mill-contaminated sediments and continuing exposure by the effluents may still have effects on biota. In this study, ecotoxicological impacts in the boreal watercourse were analyzed by measuring ethoxyresorufin-O-deethylase (EROD) induction from wild fish populations and from experimentally exposed fish. In order to assess the role of sediment-borne chemicals, juvenile rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory to the surface sediments of Lake Vatianjarvi and Southern Lake Saimaa, both watercourses impacted by the chemical wood industry for approximately a century. Hepatic EROD activity was also me…

Magnetometry in Environmental Sciences : Studying Environmental Structure Changes and Environmental Pollution

2018

Valutazione dei processi erosivi e ipotesi di intervento per la conservazione del sito archeologico di monte Alburchia

2010

Calibrazione del modello SEDD con l'impiego di un rilievo laser scanner terrestre

2009

Sedimentology and vertebrate fossils of the Frasnian Ogre Formation, Gurova outcrops, eastern Latvia

2020

Combined sedimentological and palaeontological study of the siliciclastic sequence of the Ogre Formation in the easternmost area of its distribution in Latvia was aimed at the facies analysis of the deposits and at detailed observation of the taxonomical and taphonomical peculiarities of the fossil vertebrate assemblage. Two facies associations, tidally-influenced fluvial channels and lateral tidal bars, have been identified in exposures along the Gurova River. Sedimentological evidences suggest that the studied deposits were formed in the fluvial environment with strong tidal influence. The sedimentary concentrations of vertebrate remains, dominated by the antiarch Bothriolepis maxima, por…

Depositional environment of the tidally-dominated transgressive succession: Rēzekne and Pärnu regional stages, Baltic devonian basin

2013

Disertācijas pētijumu tēma ir veltīta Rēzeknes un Pernavas reģionālo stāvu nogulumu fāciju pētījumiem un to uzkrāšanās vides rekonstrukcijai Baltijā. Agrākie pētījumi šajā devona klastisko nogulumu slāņkopas daļā tika veltīti galvenokārt litoloģiskiem, mineraloģiskiem un stratigrāfiskiem pētījumiem, kā arī nogulumu sastāva pētījumiem baseina austrumdaļā. Detalizēti pētījumi ar mērķi rekonstruēt kopējo baseina attīstību līdz sim netika veikti. Tādēļ, Rēzeknes un Pērnavas reģionalo stavu slāņkopas veidošanas apstākļi bija maz zināmi, kā arī diskutabli. Pēdējo desmit gadu laikā fāciju analīzes loma seno baseinu rekonstrukcijās tika plaši pielietota vidus un augšdevona klastiskās slāņkopas pētī…