Search results for "sedimenti"
showing 10 items of 57 documents
Relazioni tra contenuto di materia organica, carbonio organico e granulometria nei sedimenti di aree di transizione
2008
To describe the geochemical features of the sediments in nine sicilian coastal lakes, 78 samples of surface sediments were collected in July 2005. Analyses of Nitrogen, Total Organic Carbon, Organic Matter, Carbonates and Grainsize were performed. A better correlation between the Organic Matter, evaluated through the Sequential-LOI, and TOC was found at 350 °C, rather than at 450 °C. Statistical analysis confirmed the similarities of the trends of TOC and LOI350 in the samples pooled according to the dominant grainsize, with the highest values associated to the medium sand fraction. The differences among the median values of the groups were significant (ANOVA, Kruskal-Wallis; P<0.001). The …
The influence of lipid content and taxonomic affiliation on methane and carbon dioxide production from phytoplankton biomass in lake sediment
2021
The greenhouse gases methane (CH4) and carbon dioxide (CO2) are end products of microbial anaerobic degradation of organic matter (OM) in lake sediments. Although previous research has shown that phytoplankton lipid content influences sediment methanogenesis, current understanding on how OM quality affects methanogenesis is still limited. Such information is needed to more accurately assess how lake greenhouse gas emissions may change in response to anthropogenic activities. We cultured 11 phytoplankton species from five classes and studied how taxonomic identity, C : N ratio, lipid content, and fatty acid composition of phytoplankton biomass affects the CH4 and net CO2 production in anaero…
Indagini sulla stima della produzione di sedimenti mediante l'impiego della tecnica del cesio-137. Il caso del torrente Trionto in provincia di Cosen…
2006
Kangasalan Vesijärven ekologisen tilan kehitys 1800-luvulta nykypäivään : paleolimnologinen tutkimus
2015
Kangasalan Vesijärvi eteläisessä Suomessa on melko kirkasvetinen ja keskisyvyydeltään matalahko (6 m) järvi, jossa tilavuudeltaan suuri tuottava kerros aiheuttaa alttiutta rehevöitymiselle. Tässä paleolimnologisessa tutkimuksessa tarkasteltiin sedimenttiin kertyneiden surviaissääski- ja piileväjäänteiden sekä sedimenttikerrostumien fysikaalisten ja kemiallisten ominaisuuksien avulla Kangasalan Vesijärven ekologisen tilan kehityshistoriaa 1800-luvun lopulta nykypäivään. Piileväyhteisö alkoi muuttua 1920-luvun lopulla kohti rehevämpiä olosuhteita suosivaa lajistoa ja muutokset jatkuivat 1970-luvulle, jonka jälkeen yhteisön lajikoostumus vakiintui. Surviaissääskiyhteisö alkoi vastaavasti muutt…
Occurrence of pharmaceuticals in municipal wastewater treatment plants and receiving surface waters in Central and Southern Finland
2016
The presence of five selected pharmaceuticals, four anti-inflammatory drugs, diclofenac, ibuprofen, ketoprofen, naproxen, and an antiepileptic drug carbamazepine, was determined at four municipal wastewater treatment plants (WWTPs) and in the receiving waterway near the city of Jyväskylä, in central Finland and also in the River Vantaa. First, an analytical method was developed including a pretreatment and purification followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The studied pharmaceuticals were detected from influents and effluents of four municipal WWTPs and from surface water of eight locations along the water …
Bacterial Diversity in a Dynamic and Extreme Sub-Arctic Watercourse (Pasvik River, Norwegian Arctic)
2020
Microbial communities promptly respond to the environmental perturbations, especially in the Arctic and sub-Arctic systems that are highly impacted by climate change, and fluctuations in the diversity level of microbial assemblages could give insights on their expected response. 16S rRNA gene amplicon sequencing was applied to describe the bacterial community composition in water and sediment through the sub-Arctic Pasvik River. Our results showed that river water and sediment harbored distinct communities in terms of diversity and composition at genus level. The distribution of the bacterial communities was mainly affected by both salinity and temperature in sediment samples, and by oxygen…
Development of temperature and oxygen gradients during the formation of ice cover in a deep boreal lake
2008
Autochthonous organic matter promotes DNRA and suppresses N2O production in sediments of the coastal Baltic Sea
2021
Coastal environments are nitrogen (N) removal hot spots, which regulate the amount of land-derived N reaching the open sea. However, mixing between freshwater and seawater creates gradients of inorganic N and bioavailable organic matter, which affect N cycling. In this study, we compare nitrate reduction processes between estuary and offshore archipelago environments in the coastal Baltic Sea. Denitrification rates were similar in both environments, despite lower nitrate and carbon concentrations in the offshore archipelago. However, DNRA (dissimilatory nitrate reduction to ammonium) rates were higher at the offshore archipelago stations, with a higher proportion of autochthonous carbon. Th…
Biotisko un abiotisko faktoru ietekme uz makroaļģu izplatību Rīgas līča piekrastē
2015
Darbs ir veltīts tādai sugu grupai, kā makroaļģes, kas ir gan biotopu veidojošas sugas, kas nodrošina ekosistēmai svarīgas funkcijas un raksturo attiecīgās ūdens ekosistēmas stāvokli un struktūru, kā arī veido vērtīgus biotopus. Tā kā nav iespējams apsekot plašas teritorijas, lielu izmaksu dēļ, vairāku pētījumu ietvaros tikuši pētīti makroaļģu izplatībai piemērotie apstākļi, balstoties uz kuriem būtu iespējams modelēt konkrētu makroaļģu izplatību. Pētījuma mērķis bija noskaidrot faktorus, kas ietekmē makroaļģu izplatību tieši Rīgas līča piekrastē, par pamatu ņemot literatūrā izdalītos faktorus. Pētījuma rezultātā tika konstatēts, ka abās Rīgas līča piekrastēs būtiska ietekme uz makroaļģu pā…
TRATTAMENTO DI SEDIMENTI MARINI MEDIANTE REATTORI BIOSLURRY: ANALISI DI PROCESSO E CARATTERIZZAZIONE MICROBIOLOGICA
2020
I sedimenti, elementi essenziali e dinamici di tutti i sistemi acquatici, rappresentano un potenziale serbatoio di sostanze tossiche di origine antropogenica. In ambiente marino, essi costituiscono un comparto ambientale estremamente complesso, con modalità di formazione, caratteristiche chimico-fisiche, organismi viventi e tipi di contaminazione estremamente variabili. In particolare, gli idrocarburi di origine petrolifera (indicati globalmente con la misura dei TPH - Total Petroleum Hydrocarbon) inquinanti prioritari particolarmente diffusi nelle aree fortemente industrializzate, tendono a rimanere intrappolati nei sedimenti per lunghi periodi di tempo; ciò li rende una fonte permanente d…