Дисертації з теми "Dissolved and particulate phases"
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1
Audoux, Thomas. "Approches expérimentales pour l’étude et la caractérisation des dépôts humides d’aérosols atmosphériques par les précipitations." Electronic Thesis or Diss., Université Paris Cité, 2022. http://www.theses.fr/2022UNIP7332.
Повний текст джерелаАнотація:
Dans le cadre de mon travail de thèse, je me suis intéressé aux aérosols atmosphériques et à leur transfert de l’atmosphère vers les surfaces terrestres par les précipitations. La stratégie générale que j’ai suivie repose sur l’observation des dépôts humides sur différentes échelles de temps, interannuelle d’une part et intraévènementielle de l’autre. Elle repose aussi sur leur observation dans des environnements marqués en termes de charge et de composition en aérosols, mais aussi de dynamiques atmosphériques et de précipitations. Le fait de combiner des mesures à la fois sur la composition de l’atmosphère et sur la composition des dépôts humides permet d’identifier la nature des dépôts (intensité, composition, source et provenance) et d’expliquer les phénomènes impliqués dans les dépôts. Cela passe par la documentation complète de différents paramètres (aérosols, dynamique, pluie, dépôt) sur les mêmes périodes de temps, ce qui est néanmoins complexe à mettre en oeuvre. Les deux axes de mon travail portent sur des questions distinctes et complémentaires de l’étude des dépôts humides.Le premier axe s’est porté sur les dépôts humides au Sahel, région semi-aride où le lessivage des poussières minérales de l’atmosphère est un processus clé pour contraindre le bilan atmosphérique en masse de ces composés. Dans cette région marquée par la présence de nombreux systèmes convectifs contrôlant les quantités de précipitations annuelles, la question sur les liens entre dynamiques atmosphériques et dépôts s’est alors posée. La stratégie d’observation long-terme mis en place sur les stations au Sahel dans le cadre du réseau INDAAF, avec une synergie autour de mesures météorologiques, de concentrations et de dépôts d’aérosols, a permis de constituer une base de données très complète. À partir de cette base de données pluriannuelle aux stations de Banizoumbou (Niger) et de Cinzana (Mali) de 2007 et 2015, l’identification de phénomène de cold pools (gouttes froides) à partir de données météorologiques de surface et leur lien avec les retombées de poussières minérales sont discutés. Les ratios de lessivage ont été calculés pour les évènements associés aux cold pools et varient sur plusieurs ordres de grandeur en fonction de l’effet de dilution qui diffère selon les régimes de concentrations atmosphériques en poussière minérale. Les évènements les plus convectifs associés à des concentrations élevées présentent une gamme de valeurs moins dispersée (319 – 766) qui ne dépend pas de la quantité de précipitation.Le second axe s’est focalisé sur l’étude intraévènementielle des dépôts en milieu urbain pour diverses situations de pluie, de concentration et composition en aérosols. Que peut nous apprendre le suivi des dépôts au cours d’un évènement de pluie ? Pour y répondre, j’ai tout d’abord participé au développement d’un collecteur me permettant de collecter les dépôts humides en fractions successives au cours de la pluie. Complétées par un ensemble de mesures colocalisées sur les aérosols et les dynamiques atmosphériques acquises sur le terrain pour 8 cas d’étude, les analyses chimiques des dépôts dissouts et particulaires m’ont permis de discuter à la fois la provenance des aérosols, mais aussi les processus mis en jeu. J’ai pu quantifier la décroissance des concentrations, même de composés traces, dans les dépôts au cours de la pluie. J’ai également pu documenter l’évolution de la solubilité pour les espèces chimiques des dépôts et discuter des poids relatifs des mécanismes de lessivage dans- (rainout) et sous- (washout) le nuage. La variabilité des dépôts observée au cours d’un évènement est au final aussi importante que celle observée entre évènements de pluieIn the work conducted for my thesis, I studied atmospheric aerosols and their transfer from the atmosphere to the surface by precipitation. The main strategy I followed is based on the observation of wet deposition on different time scales, interannual on one hand and intra-event on the other. It also relies on their observation in environments marked in terms of aerosol load and composition, but also in terms of atmospheric dynamics and precipitation. Combining measurements on both atmospheric and wet deposition compositions allows to identify the characteristics of the deposition (intensity, composition, source and origin) and to explain the phenomena involved in the deposition. This requires the complete documentation of different parameters (aerosols, dynamics, rainfall, deposition) over the same periods of time, which is nevertheless complex to implement. The two axes of my work deal with distinct and complementary issues in the study of wet deposition.The first focus has been on wet deposition in the Sahel, a semi-arid region where the scavenging of mineral dust from the atmosphere is a key process to constrain the atmospheric mass balance of these compounds. In this region marked by the presence of numerous convective systems controlling annual precipitation amounts, the question of the links between atmospheric dynamics and deposition was addressed. The long-term observation strategy implemented at stations in the Sahel as part of the INDAAF network, with a synergy of meteorological measurements, aerosol concentrations and deposition, has enabled the creation of a very complete database. From this multi-year dataset at Banizoumbou (Niger) and Cinzana (Mali) stations from 2007 and 2015, the identification of cold pools phenomena from surface meteorological data and their link with mineral dust deposition are discussed. Washout ratios have been calculated for cold pool events and vary over several orders of magnitude depending on the dilution effect which differs according to the levels of atmospheric aerosol concentrations. The most convective events associated with high concentrations have a less scattered range of values (319 – 766) that does not depend on the amount of precipitation.The second axis focused on the intra-event study of wet deposition in urban areas for various rainfall situations, aerosol concentration and composition. The question is: what can we learn from the monitoring of deposition during a rain event? To answer this, I first participated in the development of a collector allowing me to collect wet deposition in successive fractions during the rain event. Complemented by a set of co-located measurements on aerosols and atmospheric dynamics acquired in the field for 8 study cases, the chemical analyses of dissolved and particulate deposition allowed me to discuss both the origin of the aerosols and processes involved. I was able to quantify the decay of concentrations, even of trace compounds, in the deposits during rainfall. I was also able to document the evolution of solubility for chemical species in the deposition and discuss the relative contribution of the rainout and washout mechanisms. The variability of deposition observed during an event is actually as significant as that observed between rain events
2
Mudashiru, Liadi K. "Electrochemical determination of dissolved and particulate iron in mine-waters." Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/1136.
Повний текст джерелаАнотація:
A voltammetric procedure for the determination of dissolved and colloidal iron in mine-waters has been developed. Whilst mine-waters are of course enriched in iron. we are remarkably ignorant of the physical state and chemical speciation of the iron. This is a problem since the physical and chemical state of iron is central to understanding a range of processes relevant to mine-water geochemistry and remediation. Examples include hydrolysis of dissolved Fe (III) to release protons. the adsorption of trace metals onto iron colloids and the bioavailability of iron within wetlands designed to remediate acidic waters. In this work, we have developed differential pulse voltammetry (DPV) as a rapid and robust method of determining the concentration of truly dissolved and colloidal iron in 0.45 J.lm filtered waters from a series of mine-water discharges and remediation sites in NE, England. Mine-water samples were collected from CoSTaR sites: these are abandoned mine sites in the UK, designated by the UK Coal Authority for remediation research and routine monitoring of water quality. The sites comprise of six full-scale bioreactors receiving a wide range of mine-waters with pH ranging from 3 to 5 and concentrations of < 0.45 Jlm iron between 30 and 800 mg L-1 across the sites. Monthly samples were collected over the period March 2006 to April 2007. The samples were analysed directly using differential pulse voltammetry (DPV) at gold electrode. The results show that our analysis provides data for total dissolved iron of comparable analytical quality to the established mine-water analysis techniques based on inductively couple plasma spectroscopy (ICP-OES). The good agreement between the iron concentrations measured in acidified samples electrochemically and by ICPOES validates the accuracy of DPV as an analytical method for iron. Colloidal and particulate iron was also determined since DPV measures only dissolved iron. particulate (>0.45 Jlm) and/or colloidal «0.45 Jlm) iron can then be estimated as the difference between the voltammetric responses of natural samples and samples in which the solid phase iron has been dissolved by the addition of He!. v The percentage dissolved iron ranged from 60-90% (in most cases) in unfiltered samples, while the percentage of colloidal iron varied widely across the sites; from 25-45% in unfiltered samples and 50-75% and 38-85% for dissolved and colloidal iron in the 0.45 Jim filtered samples. The ratio of Fe (II) to Fe (III) in the dissolved fraction was detennined usmg ultramicroelectrodes (UME) method. Iron ratio varied widely for the three sites studied. However, in general, the ratio is 1: 1 for the surface influent waters. 1:3 for the sub-surface waters (underground water-Shilbottle site) and 3: 1 for most of the effluent samples. Results suggest that in general, the influent waters are more oxidised and the effluent more reduced. Finally, characterisation of solid phase iron was done usmg a wide range of spectroscopic techniques. Atomic Force Microscopy (AFM) shows that iron colloids range from nm to Jim for lower pH mine waters; at higher pH, particles mainly aggregates on the Jim to mm scale. FT-IR, XRD, TEM and EDX show that the most common colloidal phase is poorly crystalline Fe oxyhydroxides, however certain unusual crystalline phases, e.g., Schwertmannite were found.
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Laslett, Rebekah E. "Dissolved and particulate trace metals in the Forth and Tay estuaries." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/11033.
Повний текст джерелаАнотація:
The estuarine biogeochemistries of Cd, Cu, Mn, Ni, Pb and Zn have been examined. Two adjacent, contrasting estuaries were selected to assess the effects of riverine discharge, hydrodynamic régime and particulate phase composition. Sampling throughout an annual cycle enabled seasonal differences in primary productivity and meteorological conditions to be included. Simultaneous nutrient determinations and fresh water flow measurements were used to assist in the interpretation of metal data. Dissolved Mn profiles in both estuaries are dominated by benthic inputs, a consequence of the reduction of Mn in sub-oxic sediments. Highest benthic fluxes occur in summer, and coincide with dissolved oxygen minima in the upper Forth. High wintertime fluxes are caused by the injection of porewater following sediment resuspension. Dissolved Ni and Zn are remobilised with Mn during summer in the Forth. Dissolved Cd concentrations in both estuaries increase with salinity as a result of chloro-complexation. Both Cd and Cu are remobilised during the breakdown of particulate material. Only about 5% of the Pb is in the dissolved phase. Suspended particulate trace element contents do not vary much within each estuary. The Ca contents, however, increase with distance seaward, since the coastal zone acts as a source of CaCO3 to the estuaries. Non-detrital Mn contents increase in the outer Forth during summer, a consequence of precipitative Mn oxidation. The behaviours of Ni and Zn mimic that of Mn, as they are scavenged from the dissolved phase by newly formed particulate Mn oxides. Particulate Mn contents are higher in summer than in winter, and higher in the well-oxygenated Tay than in the Forth. This is attributed to faster Mn oxidation rates at higher temperatures and dissolved oxygen concentrations. Suspended particulate Cd contents in both estuaries are highest in summer due to the binding of Cd to phytoplankton cells. Partition coefficients in the Forth and Tay follow the order Pb > Mn, Zn > Ni > Cu > Cd.
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Abell, Russell H. III. "Scavenging of particulate and dissolved lead compounds by coprecipitation with manganese oxyhydroxides." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36674.
Повний текст джерелаАнотація:
Mn is a geochemically important element that contributes significantly to the cycling of heavy metals. During precipitation, Mn oxyhydroxides scavenge many heavy metals, including Pb, in a variety of natural environments. Because of this phenomenon, the precipitation of Mn oxyhydroxides may provide a remediation technique for removing Pb from contaminated aqueous solutions. Therefore, this study was undertaken to provide a quantitative understanding of the coprecipitation of Pb with Mn oxyhydroxides to demonstrate their capacity to remove Pb permanently from contaminated solutions. To accomplish this, a series of factorial experiments with varying initial Mn and Pb concentrations were run in the presence of a borate buffer or a bicarbonate buffer. All experiments were run in batch reactors, in the presence of a quartz substrate, at 25 degrees celcius, at pH 8.5, and were continuously stirred. Initial Mn and Pb concentrations were varied by half log units from 100 to 0 mg/L and from 3 to 0 mg/L, respectively. Solutions were analyzed for Mn using the formaldioxime colorimetric method and for Pb using AA. Precipitates on quartz surfaces were analyzed by SEM, XPS, and XRD for precipitate identification and morphology. The amount of Mn and Pb associated with the quartz sand was determined by dissolving the precipitates from selected quartz samples using concentrated nitric acid. Finally, a different set of precipitate-coated quartz grains were leached in pH 5 acetic acid solution to assess the metal retention capacity of the precipitated material.
Mn oxyhydroxides precipitated onto the quartz sand in both the borate and bicarbonate buffered experiments. SEM and XPS data revealed tiny crystallites in etch pits on the quartz surfaces that contained predominantly Mn3+. XRD analysis did not produce an X-ray pattern for these Mn oxyhydroxides but did identify the suspended Pb precipitates as hydrocerrusite and Pb(HBO3)2 in the borate buffered experiments and hydrocerrusite in the bicarbonate buffered experiments. Much more Mn and Pb are associated with the quartz surfaces in the borate buffered experiments, but no Pb was associated with quartz surfaces initially (< 6 hrs. of reaction time). Leaching of precipitates resulted in extracted Mn in both experiments but Pb was extracted in only the bicarbonate buffered experiments. The Mn precipitation rate was greater in the borate buffered experiments and higher initial Mn and Pb concentrations appear to increase the precipitation rate in both sets of experiments. These results indicate that Mn oxyhydroxides nucleated onto suspended Pb precipitates. The growing Mn oxyhydroxide particles were attracted to the quartz sand, carrying along the Pb precipitates. Further precipitation of Mn oxyhydroxides on the quartz surfaces trapped the Pb. This process was much more significant in the borate buffered experiments where much more Mn precipitated. The greater amount of Mn oxyhydroxide growth acts as a barrier protecting the Pb from the pH 5 leaching solutions. As a result, Pb was retained by the sand grains from the borate buffered experiments during leaching while significant amounts of Pb (35-100%) was extracted from the sand produced by the bicarbonate experiments. These results strongly suggest that coprecipitation of Pb with Mn oxyhydroxides in the presence of a borate buffer and a quartz substrate may be a remediation tool for Pb contaminated aqueous solutions. Not only will this process remove aqueous Pb2+ from solution but it appears it will also substantially incorporate colloidal Pb particles as well.Master of Science
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Frankki, Sofia. "Association of organic compounds to dissolved and particulate natural organic matter in soils /." Umeå : Dept. of Forest Ecology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200652.pdf.
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Dukes, Craig Harry. "Uptake of dissolved nutrients by Tetrahymena pyriformis in batch culture with particulate matter." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/10944.
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Tucker, Ashley. "GLOBAL ASSESSMENT OF RADIOCARBON ISOTOPIC ANALYSIS FOR PARTICULATE AND DISSOLVED ORGANIC CARBON IN RIVERINE SYSTEMS." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/632.
Повний текст джерелаАнотація:
Rivers are a significant source of particulate and dissolved organic carbon (POC, DOC) into inland waters and coastal systems and provide a fundamental linkage between the terrestrial, oceanic, and atmospheric carbon reservoirs. Recent studies have examined the relationship between the quantity and form (POC vs. DOC) of carbon delivered to the aquatic system; however, little is known about the age of POC and DOC exported and how the radiocarbon age may vary with latitude, topographic gradient, vegetation, and land use. I provide the first global synthesis of published radiocarbon values of POC and DOC (∆14C). Inclusion of DOC and POC parameters (µM, δ13C, ∆14C) reveal significant driving forces of DOC (µM), latitude, and elevation (m) as capable of explaining 25% of the variability in DO14C in rivers and POC (µM) and latitude accounting for 15% of the variability in PO14C. When δ13C of DOC and POC and latitude were incorporated with ∆14C of DOC observations, 61% of the variability in DOC age was explained revealing the necessity to include dissolved and particulate fractions of organic carbon to yield the most robust predictive models. This study found a global trend of increasing age of DOC and increasing δ13C of DOC and POC with increasing latitude. My study suggests future research should incorporate both particulate and dissolved OC parameters along with elevation, vegetation, land cover, and climate zones to increase understanding of what drives the age of carbon exported in riverine systems.
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Law, Ming-chu Cecilia, and 羅明珠. "The combined fouling of nanofiltration membranes by particulate solidsand dissolved organics in wastewater treatment and reuse." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43703689.
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McIntosh, Hadley Allaben. "Composition, Sources, and Age of Dissolved and Particulate Organic Matter in the Delaware River and Estuary." W&M ScholarWorks, 2013. https://scholarworks.wm.edu/etd/1539617941.
Повний текст джерелаАнотація:
Estuaries are important sites of organic matter (OM) transformation, exchange, and burial but remain one of the least understood regions in the global carbon cycle. The carbon cycle within these regions is complex due to strong gradients in biological and physical processes, and increasing anthropogenic impacts. This is further complicated by the many sources of particulate and dissolved organic matter (OM) in estuaries, including materials derived from terrestrial and anthropogenic sources as well as aquatic and marine primary production. This study combined lipid biomarker analyses with stable and radiocarbon signatures of lipids and source-specific biomarkers to better understand the sources and aging of OM in Delaware River and Bay, a model estuarine system.
The lipid composition of particulate organic matter (POM, > 0.7 μm) and ultrafiltered dissolved organic matter (UDOM, 1kDa – 0.1 μm) was investigated along the salinity gradient in the Delaware River and Bay during five separate cruises. Sources of OM associated with POM and UDOM were examined using chlorophyll a, C:N ratios, stable carbon and nitrogen isotopes (δ13C and δ15N), total lipid extracts, and fatty acid (FA) biomarker compounds. Multiple hierarchical models explored which environmental characteristics were the primary drivers of POM and UDOM composition. These models revealed that chlorophyll a, POC, and TSS influenced POM sources and composition along the estuary, while a variety of drivers influence UDOM composition.
Stable carbon (δ13C) and radiocarbon (Δ14C) measurements of dissolved inorganic carbon, bulk particulate organic carbon (OC), and neutral and polar lipids from particulate organic matter (TLEPOM) and ultrafiltered dissolved organic matter (TLEUDOM) were measured in order to gain insights about the source and age distribution of lipids along the Delaware River and Bay. Overall, Δ14C values for neutral TLE were more depleted (i.e., had “older” radiocarbon ages) than polar TLE. Radiocarbon ages for neutral TLEPOM were younger than neutral TLEUDOM by approximately 10,000 YBP, while polar TLEPOM and polar TLEUDOM were similar in age. Using a 14C isotope mass balance, changes in contributions of modern and fossil OC were quantified along the estuary for TLEPOM and in TLEUDOM. Complementary to determining the radiocarbon ages of different lipid classes, this study was the first to apply compound specific radiocarbon analyses to fatty acids (FA) associated with estuarine POM. Δ14C values indicate that the ages of terrestrial and algal FA change along the estuary. Terrestrial FA increased in age along the estuary due to downstream sources, while algal FA became “younger” along the estuary due to contributions from autochthonous sources.
FA biomarker and radiocarbon analyses revealed changing composition of OM along the Delaware River and Bay: (1) older, terrestrial sources of OM characterized riverine OM, (2) the ETM was a location of shifting sources and introduction of “older” POC, and (3) the bay was dominated by younger, marine sources of OM. Lipid age was not based on within estuary processes but on the delivery of “aged” OM from the watershed and along-estuary mixing of different sources. Overall, this study provided new insights about the sources and ages of OM along the estuarine salinity gradient and the complex processes by which they are controlled.
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Caulkett, Andrew Paul. "Studies of dissolved species and suspended particulate matter in the freshwater systems of Signy Island, maritime Antarctic." Thesis, Open University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311860.
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Dawson, Julian J. C. "The controls on concentrations and fluxes of gaseous, dissolved and particulate carbon in upland peat dominated catchments." Thesis, University of Aberdeen, 2000. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU125517.
Повний текст джерелаАнотація:
A programme of field sampling was undertaken to quantify total carbon fluxes (DOC, POC, HCO3, free CO2 and CH4) from peatland catchments in Glen Dye, NE Scotland and Plynlimon, Mid-Wales. This was integrated with temporal and spatial sampling to investigate controls on contrasting concentrations and fluxes and to determine carbon sources or sinks within the stream system. Microcosms containing radiolabelled ( 14C) biofilms were also used to investigate removal of DOC from streamwater. Carbon fluxes from acidic peatlands were dominated by DOC (115-215 kg C ha-1 yr-1) and POC (8.15-97.0 kg ha -1 yr-1). In the majority of headwaters studied, DIC was exported as free CO2 (2.62-8.49 kg ha-1 yr -1). Methane-C fluxes at the outlets of catchments were <0.01 kg ha-1 yr-1. Small-scale (diurnal) temporal variations in free CO2, HCO3- and pH at the NE Scotland catchments were small compared to more productive systems; DOC showed no diurnal fluctuations. In addition, diurnal patterns were masked by marked variations in discharge. Small-scale downstream spatial changes in Brocky Burn, NE Scotland and the Upper Hafren, Mid-Wales showed that variation in climate, in particular precipitation, was also a major controlling factor on concentrations and fluxes of the different forms of carbon. However, the actual amount of carbon stored within the soils acted as an initial control on the potential DOC load within the streamwater. A peatland stream continuum linked to terrestrial carbon cycling is presented. Initially terrestrial inputs of DOC, POC, free CO2 and CH 4 dominated the upper headwaters. The soil-stream linkage was progressively reduced downstream due to autochthonous and atmospheric factors. A critical area in the peatland stream continuum occurred approximately 1 km downstream from the gaseous carbon-rich peats.
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Law, Ming-chu Cecilia. "The combined fouling of nanofiltration membranes by particulate solids and dissolved organics in wastewater treatment and reuse." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43703689.
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Lee, Mi-Hee [Verfasser], and Egbert [Akademischer Betreuer] Matzner. "Dynamics of dissolved and particulate organic carbon and nitrogen in forest ecosystems / Mi-Hee Lee. Betreuer: Egbert Matzner." Bayreuth : Universität Bayreuth, 2016. http://d-nb.info/1095663623/34.
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Loh, Ai Ning. "Chemical, isotopic and microbial characterization of dissolved and particulate organic matter in estuarine, coastal and open ocean systems." W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539791565.
Повний текст джерелаАнотація:
Dissolved and suspended particulate organic carbon (DOC, POC), nitrogen (DON, PON), phosphorus (DOP, POP) and inorganic nutrient distributions and elemental ratios were measured and evaluated for the Atlantic, Southern, and Pacific Oceans. Results indicate that DOC is remineralized during mean deep-water transport from the North Atlantic to the North Pacific. Elemental ratios for both dissolved organic matter (DOM) and particulate organic matter (POM) indicate that organic N is preferentially remineralized compared with organic C, while organic P is preferentialy remineralized relative to both organic C and N. Comparison between the DOM and POM pools further suggests that surface POM may be less refractory than concurrently sampled DOM. Major compound class compositions of ultrafiltered DOM (UDOM) in the North Atlantic, North Pacific and Chesapeake Bay indicate that the majority of UDOM was comprised mainly of a molecularly-uncharacterized fraction, followed by carbohydrates, proteins and lipids. Delta14C and delta 13C results of UDOM compound classes suggest that UDOM in Bay mouth and surface open ocean waters were similarly dominated by old, marine sources, while UDOM from the freshwater endmember was influenced by much younger terrestrial sources. Results indicate that DOM is comprised of different aged organic fractions and provide evidence for a potential organic "size"-age continuum; from low-molecular weight DOM (oldest) to UDOM (intermediate age) to POM (youngest). Lipid biomarker results indicate that North Atlantic and Pacific UDOM and POM were relatively more reactive at the surface compared with greater depths, coinciding with elemental C:P and N:P ratios greater than Redfield. Factor analyses suggest that there exists a "lability continuum" spanning from surface ocean POM to riverine and deep ocean UDOM. Terrigenous organic material was found at all Bay sites although autochthonous sources of organic matter were also important. Dark microbial incubations of DOM from the Pacific Subtropical Front and South Atlantic Bight indicate that open ocean DOM is relatively refractory over short time scales (less than 2 months). Experiments with plankton leachate DOM show that this sub-pool of DOM is relatively labile and is converted to refractory DOM within days. DOP is preferentially remineralized in all experiments compared with DOC or DON.
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Chen, Hongwei. "Development of analytical methodologies for iodine species in gaseous and particulate phases of the coastal atmosphere." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976812096.
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Lee, Sea-Hoon. "Processing of carbon fiber reinforced composites with particulate filled precursor derived Si-C-N matrix phases." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11814256.
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Le, Mellec Anne. "The canopy as source for dissolved and particulate organic matter (DOM, POM) - with a focus on mass outbreaks of phytophagous insects /." Aachen : Shaker, 2009. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=018961097&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Le, Mellec Anne. "The canopy as source for dissolved and particulate organic matter (DOM, POM) - with a focus on mass outbreaks of phytophagous insects." Aachen Shaker, 2008. http://d-nb.info/997950358/04.
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Loh, Ai Ning. "Distribution, Partitioning and Fluxes of Dissolved and Particulate Organic Carbon, Nitrogen and Phosphorus in the Eastern North Pacific and Southern Oceans." W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539617737.
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Ahad, Jason Michael Elias. "Evaluating the origins and transformations of organic matter and dissolved inorganic nitrogen in two contrasting North Sea estuaries." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/866.
Повний текст джерелаАнотація:
In order to delineate the potential sources and to understand the main controls on the biogeochemical cycling of dissolved and particulate organic matter (DOM, POM) and dissolved inorganic nitrogen (DIN) during estuarine mixing, comprehensive seasonal geochemical and isotopic and surveys across the freshwater-tidal interface were carried out in the Tyne and Tweed Estuaries, NE UK. This study provided a contrast between a relatively pristine system (Tweed) with one that is heavily influenced by anthropogenic activity (Tyne). Geochemical and isotopic (13C, 14C and 15N) analyses demonstrated the predominance of terrigenous organic matter in both these estuaries, with elevated river discharges leading to enhanced terrestrial loading. High pCO2 values in the Tyne (summer) and Tweed (winter) suggested that a significant fraction of this terrestrially-derived organic matter (both DOM and POM pools) is relatively labile and can potentially undergo significant mineralization during estuarine mixing. In both estuaries in situ processing of DIN was relatively minor, with mixing between different sources being the main factor in controlling the distribution of nitrate and ammonium across the salinity gradient. However, anthropogenic ammonium discharges in the Tyne were found to have an enormous direct and indirect impact on estuarine nitrogen cycling. Large, concave removals of terrigenous high molecular weight (HMW) DOC caused by flocculation, biodegradation, and/or photochemical oxidation were associated with a non-conservative 13C-enrichment in d13C signatures. Radiocarbon dates showed an export of young (modern) HMW DOC and old (100-1000s of years), terrigenous POC to the North Sea. 14C-enriched values in coastal North Sea HMW DOC were attributed to anthropogenic discharges originating from within the coastal North Sea environment. In the Tweed, seasonal changes in soil characteristics resulted in an older age for POM during the summer. In the Tyne, decreases in POC% with increasing salinity sometimes coincided with an increase in POC age. This was attributed to mixing with older sediment and to the possible preferential loss of the younger, more labile POC fraction during mineralization. This study has shown that land use patterns, sewage inputs, and freshwater flushing time are the main influences in determining the behaviour and origin of organic matter and DIN entering the coastal North Sea in these two systems.
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Randall, Benjamin. "Characterisation and quantification of the fluxes of particulate and dissolved nitrogen in the unicellular diazotroph crocosphaera watsonii : towards a closed nitrogen budget." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS685.
Повний текст джерелаАнотація:
Les flux importants de la phase N dissoute, qui renseignent sur les bilans globaux en N des diazotrophes individuels, sont mal compris. Cela est particulièrement vrai des diazotrophes récemment découverts, qui peuvent ne pas fonctionner selon des paradigmes préétablis. Crocosphaera watsonii est un de ces diazotrophes, que l'on trouve largement répandu dans les océans subtropicaux. Nous caractérisons ici les flux d'azote à la diazotrophie de Crocosphaera, y compris les flux de NO3-, NH4 + et de N organique dissous (DON). Nous visons également à utiliser nos résultats pour évaluer la précision des tests biologiques de fixation du N2 couramment utilisés. Nous avons d'abord évalué l'utilisation de NO3- par Crocosphaera. Pour ce faire, des cultures discontinues de Crocosphaera ont été cultivées à long terme avec NO3-, en mesurant l'absorption de NO3-, son effet sur la diazotrophie, la croissance de la culture et d'autres paramètres physiologiques importants. Nous avons trouvé peu d'absorption sans effet sur les paramètres évalués, y compris la diazotrophie. Nous avons ciblé la disponibilité de la lumière comme paramètre important. Entre les conditions de culture de sous-saturation (SSL) et de lumière saturante (SL), nous avons constaté une augmentation de l'acquisition de N, de l'acquisition de C et du taux de croissance cellulaire dans les conditions de SL. De plus, nous avons constaté une absorption du DON sur une période de 24 heures, avec une plus grande adoption dans le scénario SSL (42% contre 7%). Il y avait un plus grand flux de NH4 + dans le support dans le SSL. En utilisant une approche isotopique, nous avons trouvé que 2,5 à 3,5% de l'azote récemment fixé étaient exsudés 24h. Notre évaluation de l'exactitude de la méthodologie a révélé que les incubations de 15N2 sous-estimaient la fixation de N2 alors que le test de réduction à l'acétylène était surestiméDiazotrophy exists as a source of fixed N in the ocean, affecting processes like the marine food web. Important fluxes of the dissolved N phase, which inform the overall N budgets of individual diazotrophs, are poorly understood. This is especially true of recently discovered diazotrophs which may not function under pre-established paradigms. One such diazotroph is Crocosphaera watsonii, which is found widespread throughout sub-tropical oceans. Here we characterise N fluxes consequent to diazotrophy for Crocosphaera, including fluxes of NO3-, NH4+, and dissolved organic N (DON). We also aim to use our results to assess the accuracy of commonly used biological N2 fixation assays. We first assessed the use of NO3- by Crocosphaera. To do this, batch cultures of Crocosphaera were grown long term with NO3-, measuring uptake of NO3- uptake its effect on diazotrophy, culture growth and other important physiological parameters. We found little uptake with no effect on the assessed parameters, including diazotrophy. We next focussed on flux of DON and NH4+ in continuous cultures regulated for conditions such as temperature, light, and pH. We targeted light availability as an important parameter. Between culture conditions of sub-saturating (SSL) and saturating light (SL), we found an increase in N acquisition, C acquisition and cell growth rate in the SL condition. Furthermore, we found an uptake of DON over a 24h period, with greater uptake in the SSL scenario (42% v.s. 7%). There was greater flux of NH4+ into the medium in the SSL. Using an isotopic approach, we found 2.5-3.5% of recently fixed N was exuded 24h. Our assessment of the accuracy of methodology found that 15N2 incubations underestimated N2 fixation while the acetylene reduction assay overestimated. Overall, 15N2 incubations were more reliable when factoring in fluxes of dissolved N. Our findings represent new perspectives into the importance of fluxes of dissolved N to N budgets of Crocosphaera watsonii
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Hallberg, Magnus. "Treatment conditions for the removal of contaminants from road runoff." Doctoral thesis, Stockholm : [Byggvetenskap, Kungliga Tekniska högskolan], 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4386.
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Svedén, Jennie B. "Cyanobacterial Nitrogen Fixation in the Baltic Sea : With focus on Aphanizomenon sp." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132773.
Повний текст джерелаАнотація:
Cyanobacteria are widely distributed in marine, freshwater and terrestrial habitats. Some cyanobacterial genera can convert di-nitrogen gas (N2) to bioavailable ammonium, i.e. perform nitrogen (N) fixation, and are therefore of profound significance for N cycling. N fixation by summer blooms of cyanobacteria is one of the largest sources of new N for the Baltic Sea. This thesis investigated N fixation by cyanobacteria in the Baltic Sea and explored the fate of fixed N at different spatial and temporal scales. In Paper I, we measured cell-specific N fixation by Aphanizomenon sp. at 10 ºC, early in the season. Fixation rates were high and comparable to those in late summer, indicating that Aphanizomenon sp. is an important contributor to N fixation already in its early growth season. In Paper II, we studied fixation and release of N by Aphanizomenon sp. and found that about half of the fixed N was rapidly released and transferred to other species, including autotrophic and heterotrophic bacteria, diatoms and copepods. In Paper III, we followed the development of a cyanobacterial bloom and related changes in dissolved and particulate N pools in the upper mixed surface layer. The bloom-associated total N (TN) increase was mainly due to higher particulate organic N (PON) concentrations, but also to increases in dissolved organic nitrogen (DON). About half the PON-increase could be explained by the sum of N-fixing cyanobacteria, other phytoplankton (>2µm) and zooplankton, indicating that production was stimulated by the N fixation. In Paper IV, we used a growth model based on measured photosynthesis–irradiance relationships to explore the production potential of Aphanizomenon sp. The model included data on irradiance, biomass, temperature and light attenuation (1999–2013). Until the bloom peak, the modelled production matched the measured biomass, indicating low production losses. Over the whole season, the modelled production could explain a substantial part of the summer TN increase, assuming that plausible losses (such as grazing or cell lysis) are retained within the upper mixed layer. Complementing the other data, we also investigated the nutrient content (Paper I) and varying cell width (Paper IV) of Aphanizomenon sp. By a combination of approaches, this thesis has contributed new information on cyanobacterial N fixation rates, the transfer of fixed N to other organisms in the food web and shown the potential for fixed N to stimulate summer primary and secondary production in the Baltic Sea.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.
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Jorge, Danilo Custódio. "Particulate carbon in the atmosphere: distribution aging and wet deposition." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16829.
Повний текст джерелаАнотація:
Doutoramento em Ciências e Engenharia do AmbienteDuring the last decades a significant number of studies was performed about the cycling of carbonaceous matter in the atmosphere. Despite the efforts of the scientific community, a full understanding about the composition and formation of carbonaceous aerosol in ambient air was not yet achieved, reflecting the great variety of emitting sources and the complexity of transformation processes in the atmosphere. In addition, very little is known about a specific type of carbonaceous aerosol: the indoor carbonaceous aerosol. Removal of particulate carbonaceous matter from the atmosphere is another component of the carbon cycle that has received poor attention from researchers. The main aim of this work was to contribute to a better understanding of the sources, transformation processes and removal of atmospheric carbonaceous matter. Particulate matter, organic carbon (OC) and elemental carbon (EC) concentrations were measured simultaneously in the indoor and outdoor air of residences located in urban and sub-urban areas of northwestern Mainland Portugal. Average indoor to outdoor ratios (I/O) for OC were higher than 1 in occupied residences, showing that indoor sources, such as cooking, smoking, biomass burning and movement of people, strongly influenced indoor OC concentrations. In contrast, I/O ratios for EC were close to 1, except for a smokers’ residence, suggesting that indoor concentrations were mainly controlled by outdoor sources, most likely from vehicular emissions and biomass burning. Aerosol composition was also evaluated during one year in a kerbside site located in a busy road of Oporto. Road traffic, local dust and biomass burning were found to be the most important sources of aerosol particles. Most of the aerosol constituents exhibited well-defined temporal variations, which were related with the seasonal variability of source strengths, atmospheric processes and climatic conditions. In addition, precipitation samples were collected and characterized for chemical constituents at a background site in the Azores Islands and an urban site in the city of Oporto. Transport from continental areas bordering the North Atlantic Ocean were the main source of EC in the Azores. Both local emissions and long-range transport explained the levels of water soluble organic carbon found in the same samples. Concentrations of carbonaceous matter in Oporto were considerably higher than those measured before in other background areas in Portugal, indicating a significant atmospheric contamination by anthropogenic activities.
Nas últimas décadas foram desenvolvidos vários estudos sobre a circulação atmosférica da matéria carbonácea. Contudo, apesar dos esforços da comunidade científica, não se conseguiu ainda compreender detalhadamente a composição e a formação do aerossol carbonáceo no ar ambiente, o que reflete a grande variedade de fontes emissoras e a complexidade dos processos de transformação que ocorrem na atmosfera. Acresce ainda que se sabe muito pouco sobre um caso particular do aerossol de carbono: as partículas carbonáceas em suspensão no ar interior. Outra componente do ciclo do carbono que tem merecido pouca atenção da comunidade científica é a remoção das partículas carbonáceas da atmosfera. Este trabalho tem como objetivo principal contribuir para um melhor conhecimento sobre as fontes, processos de transformação e remoção da matéria carbonácea presente na atmosfera. As concentrações de matéria particulada, carbono orgânico (CO) e carbono elementar (CE) foram medidas simultaneamente no ar interior e exterior de residências localizadas em áreas urbanas e sub-urbanas da região nordeste de Portugal Continental. Os valores médios da razão entre as concentrações no ar interior e exterior (I/E) para o CO foram superiores a 1 para as residências com ocupantes, mostrando que as fontes interiores, como a confeção de alimentos, a queima de biomassa e o movimento de pessoas, influenciaram fortemente os teores de CO. Pelo contrário, obtiveram-se valores médios próximos de 1 para a razão I/E do CE, excluindo uma residência de fumadores, sugerindo que as concentrações deste componente eram controladas por fontes externas, muito provavelmente o tráfego automóvel e a queima de biomassa. A composição do aerossol foi também avaliada durante um ano num local confinante com uma estrada de tráfego intenso na cidade do Porto. Verificou-se que as principais fontes emissoras de partículas eram o tráfego automóvel, as poeiras do solo e a queima de biomassa. Muitos dos constituintes do aerossol mostraram variações temporais bem marcadas, as quais foram relacionadas com a variabilidade sazonal das fontes emissoras, dos processos atmosféricos e das condições climáticas. Procedeu-se ainda à recolha de amostras de precipitação e posterior caracterização química num local de fundo do arquipélago dos Açores e num local urbano da cidade do Porto. A principal fonte do CE nos Açores é o transporte a longas distâncias a partir das áreas continentais que envolvem o Atlântico Norte. Os teores de carbono orgânico insolúvel tiveram origem tanto em emissões locais como no transporte a longas distâncias. As concentrações de matéria carbonácea no Porto mostraram-se substancialmente superiores às que tinham sido medidas em áreas remotas de Portugal, indicando uma contaminação significativa por atividades antropogénicas.
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Mellec, Anne le [Verfasser]. "The canopy as source for dissolved and particulate organic matter (DOM, POM) – with a focus on mass outbreaks of phytophagous insects / Anne le Mellec." Aachen : Shaker, 2009. http://d-nb.info/1159834970/34.
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Sörensen, Malin Helena. "Mesostructured particulate silica materials with tunable pore size : Synthesis, characterization and applications." Doctoral thesis, KTH, Ytkemi (stängd 20081231), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10089.
Повний текст джерелаАнотація:
Colloidal assemblies of surfactants and polymers in aqueous solutions have been used by human mankind for hundreds of years and they are of great importance in many of our technological processes, such as fabrication of soap and papermaking. Less than two decades ago the idea of using colloidal assemblies as templates of inorganic materials was borne. A new population of materials, referred to as surfactant templated materials, took form. These materials showed extraordinary properties such as monodisperse pore size distribution, large surface areas and pore volumes. The main focus of this thesis has been on synthesis and functionalisation of spherical mesostructured silica particulate materials. In the first part of the work, mesostructured materials with expanded pores have been produced using a well established aerosol-based method as well as the newly developed emulsion and solvent evaporation (ESE) method. Increase in pore size was realized through using Pluronic block copolymer F127 together with a swelling agent poly(propylene glycol) as template. The influence of the swelling agent on pore size expansion was shown to have a roughly linear relationship. Furthermore, the impact of synthesis parameters on internal and exterior morphology has been investigated. Accessibility of the internal pore space, as well as the external surface roughness were shown to be highly dependent on synthesis temperature. Additionally, a very interesting well ordered 3D closed packed (P63/mmc) material was produced using the ionic surfactant C16TAB as template in the ESE method. In the second part of the thesis work, mesoporous spheres with large pore size, having either hydrophilic or hydrophobic surface properties, were used as carriers of an enzyme, lipase. The enzymatic activity of lipase was increased onto the hydrophobic surface, compared to lipase immobilized into the hydrophilic support as well as for lipase free in solution. This effect was probably due to a combination of enhanced hydrophobic interactions preventing denaturation of the enzyme and interfacial activation of the enzyme. This study generated an inorganic carrier material that is a promising candidate for biocatalysis applications. Additionally, mesoporous spheres were used as carriers of a model drug, Ibuprofen, to study the effect of polyelectrolyte multilayers on release properties. However, these layers were shown impermeable independent on pH and the substance was only released from uncoated particles.QC 20100811
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Haas, Peter Andrew. "Changes in concentration and composition of dissolved and particulate organic matter in the upper San Pedro River, Arizona, in response to changes in flow regime." Thesis, The University of Arizona, 2003. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0215_sip1_w.pdf&type=application/pdf.
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Kelsey, Scott Alan. "Impact of Land Use on Headwater Stream Organic and Inorganic Carbon Export in a Temperate Midwestern Experimental Watershed." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460651004.
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Brown, Matthew T. "The distribution and behavior of dissolved and particulate aluminum in coastal waters of the northeast Pacific off Oregon and Washington and in the northern Gulf of Alaska /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
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Campbell, Vivian. "The effect of chloride concentration and temperature on the partitioning of Cd, Cu and Pb between the dissolved and solid phases of an urban stormwater detention pond." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/MQ46007.pdf.
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Minnis, Rochelle J. "Comparison of the use of single and multiple oxidants on the generation of particulate matter in water distribution systems derived from groundwater sources containing hydrogen sulfide and dissolved organics." [Tampa, Fla] : University of South Florida, 2005. http://purl.fcla.edu/usf/dc/et/SFE0001390.
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Bibian, João Paulo Rambelli. "Caracterização hidrogeoquímica da microbacia de drenagem do córrego Barra Bonita, São Paulo." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-14032008-084944/.
Повний текст джерелаАнотація:
O estudo da microbacia de drenagem do córrego Barra Bonita, (S: 22º 25\' 53,9\" ; O: 48º 32\' 34,8\") objetivou a caracterização de seus parâmetros hidrogeoquímicos utilizando-se os modelos de transporte de materiais nas fases dissolvida e particulada para identificar as relações entre os processos de ocupação do solo e qualidade da água. Pelo fato de não existir um zoneamento ambiental no município, este estudo foi pioneiro investigação da qualidade ambiental da microbacia, contribuindo diretamente em futuros planos de conservação e utilização de suas águas superficiais para abastecimento público. O estudo foi conduzido de setembro de 2005 a dezembro de 2006 em quatro córregos principais formadores da microbacia, sendo selecionados oito pontos de amostragem de montante a jusante para coletas de água durante as diferentes fases da hidrógrafa. Além disso, uma amostragem intensiva foi realizada durante um evento de chuva para melhor acompanhamento dos mecanismos de transporte de materiais dissolvidos e particulados. O protocolo analítico empregado neste estudo possibilitou a determinação de variáveis hidrogeoquímicas como vazão, concentração de sedimentos em suspensão e sua caracterização isotópica quanto ao carbono e nitrogênio orgânico particulado, concentração de íons maiores dissolvidos, transporte de material dissolvido e particulado, concentração de metais em solução, sua biodisponibilidade nos sedimentos aquáticos, separação das componentes superficial e subterrâneo no escoamento total da microbacia e mecanismos de aporte difuso e pontual da carga dissolvida e particulada em escalas espaciais e temporais. Com relação ao material dissolvido na microbacia, as espécies químicas apresentaram comportamento de diluição com o aumento das vazões, predominando, portanto os aportes pontuais de carga dissolvida na microbacia. Por outro lado, durante o evento de chuva estudado as concentrações apresentaram aumento em função das vazões, destacando-se a origem superficial das espécies química nestas condições. As espécies químicas predominantes foram o HCO3-, Na+ e Ca2+, as quais estiveram relacionadas tanto à formação geológica da região quanto à aportes pontuais por meio de aplicação de insumos agrícolas como gesso, calcário e vinhaça. A parte agrícola da microbacia apresentou maior contribuição à carga dissolvida transportada durante o período considerado como chuvoso, enquanto os aportes pontuais de efluentes domésticos e de águas urbanas sobressaíram-se durante o período de seca. O material particulado em suspensão apresentou correlacionamento significativo com o incremento das vazões, sendo a parte agrícola a principal responsável pela carga transportada pela microbacia. A caracterização isotópica do material orgânico particulado para o carbono e nitrogênio evidenciou os processos de fracionamento da assinatura isotópica da matriz de plantas C4 (cana de açúcar) presente na microbacia, estando tais processos mais relacionados à degradação do material orgânico presente no solo, bem como do aporte de poluição originado da parte urbana. Apenas durante eventos de maior escoamento rápido superficial, o carbono orgânico particulado do sedimento em suspensão se aproximou do \"delta\"% das plantas C4. As concentrações de metais dissolvidos foram bastante baixas conforme o esperado, destacando-se o Fe e Al que estiveram mais relacionados ao tipo de solo da região. A biodisponibilidade de metais nos sedimentos aquáticos também foi baixa em relação a bacias hidrográficas mais industrializadas.The study in the Barra Bonita stream small watershed (S: 22o 25\' 53,9\" and W: 48o 32\' 34,8\") aimed to characterize its hydrogeochemical parameters by dissolved and particulate material transport models to identify the relations between soil use and water quality. Because there was no longer an environmental zoning in the municipality of Barra Bonita, this study was pioneer on the watershed environmental investigation, which may contribute directly to future conservation plans for the utilization of this water source as public supplying. The study was conducted from September 2005 to December 2006 in four main watershed tributaries where eight sampling points were established, upstream to downstream, for water sampling along with the hidrogram phases. Besides that, an intensive sampling excursion was carried out during a storm event in order to achieve better data about the dissolved and particulate material transport. In this study were analyzed the following hydrogeochemical parameters: discharge, major dissolved ions, suspended sediments concentrations and their isotopic characterization for particulate carbon and nitrogen, dissolved and particulate transport, dissolved metals concentration and the biodisponibilty of metal from the bottom aquatic sediments, superficial and sub superficial components of the total discharge and the punctual and diffuse input mechanisms of dissolved and particulate load for spatial and time scales. For the dissolved material in the watershed the major chemical species presented decreased concentrations with the discharge, showing the dominance of punctual input processes in the watershed. On the other hand during the storm flow event the ions concentrations increased with the discharge, showing their superficial origins in this condition. The dominant chemical species were HCO3-, Na+ and Ca2+, which were related to the regional geological formation and punctual input by agriculture like gypsum, liming and stillage. The agricultural area of the watershed presented the major contribution to the transported dissolved load in thee rainy period while the punctual inputs of domestic sewage and urban waters more important in the dry period. The suspended particulate material showed significant correlation with the discharge increasing and the agricultural part was source of the total transported load in the watershed. The isotopic characterization of the particulate organic carbon and nitrogen showed the fractioning processes of the isotopic signature from the C4 plants (sugarcane) matrix presented in the watershed, which were more related to the soil organic matter mineralization as well as with the pollution input from the urban area Only at high flows periods the particulate organic carbon was to the C4 \"delta\"% values. The dissolved metals concentrations were low as previewed, except for Fe and Al that were related to the regional soil types. The metals biodisponibility in the bottom aquatic sediments were also low in relation to more industrialized regions
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Roeske, Tobias [Verfasser], van der Loeff Michiel [Akademischer Betreuer] Rutgers, Michael [Akademischer Betreuer] Schlüter, and Wolfgang [Akademischer Betreuer] Bach. "Dissolved Barium and Particulate Rare Earth Elements as Tracers for Shelf-Basin Interaction in the Arctic Ocean / Tobias Roeske. Gutachter: Michael Schlüter ; Wolfgang Bach. Betreuer: Michiel Rutgers van der Loeff." Bremen : Staats- und Universitätsbibliothek Bremen, 2011. http://d-nb.info/1071898493/34.
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Lee, Sea-Hoon [Verfasser]. "Processing of carbon fiber reinforced composites with particulate-filled precursor-derived Si-C-N matrix phases / Institut für Nichtmetallische Anorganische Materialien der Universität Stuttgart ... Vorgelegt von Sea-Hoon Lee." Stuttgart : Max-Planck-Inst. für Metallforschung, 2005. http://d-nb.info/97496963X/34.
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Franks, Matthew James. "The Role of Soil Organic Matter and Fe- and Mn-(Oxy)Hydroxide Minerals in Agriculture: Implications on Nutrient Dynamics." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1594151828787397.
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Shreckhise, Jacob Hamilton. "Phosphorus Requirement and Chemical Fate in Containerized Nursery Crop Production." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/83893.
Повний текст джерелаАнотація:
Environmental contamination issues related to phosphorus (P) in surface waters substantiates the need to identify minimally-sufficient P fertilization amounts for production of containerized nursery crops and better understand the effect of routine amendments (i.e., dolomite [DL] and micronutrient fertilizer [MF]) added to pine bark substrates on chemical fate of P fertilizer. Four studies were conducted to accomplish two overarching objectives: 1) determine the minimum P fertilization amount and corresponding pore-water P concentration needed to achieve maximal growth of common containerized nursery crops and 2) determine the effect of DL and MF amendments in pine bark on P retention during irrigation and P fractions in substrate pore-water. In a fertigation, greenhouse study, calculated lowest P-fertilizer concentration that sustained maximal growth in Hydrangea paniculata ‘Limelight’ (panicle hydrangea) and Rhododendron ‘Karen’ (azalea) was 4.7 and 2.9 mg·L⁻¹ , respectively, and shoot growth Ilex crenata ‘Helleri’ (holly) was the same when fertilized with 0.5 to 6.0 mg·L⁻¹ P. Porewater P concentrations corresponding with treatments that sustained maximal growth of panicle hydrangea, azalea and holly were as low as 0.6, 2.2 and 0.08 mg·L⁻¹ P, respectively. In a separate study, utilizing low-P controlled-release fertilizers (CRFs), shoot growth of Hydrangea macrophylla ‘P11HM-11’ (bigleaf hydrangea) produced in two ecoregions was maximal when fertilized with as little as 0.3 g CRF-P per 3.8-L container, a 50% P reduction from the industrystandard CRF. Holly required 0.2 or 0.4 g CRF-P depending on ecoregion. Mean pore-water P concentrations that corresponded with highest SDW were 0.8 and 1.2 mg·L⁻¹ for hydrangea and holly, respectively. When irrigating fallow pine bark columns containing CRF for 48 d, amending pine bark with DL and MF reduced orthophosphate-P (OP-P) leachate concentrations by ≈ 70%, most of which was retained within the substrate. In a greenhouse study, containerized Lagerstroemia ‘Natchez’ (crape myrtle) were grown for 91 d in pine bark containing CRF. In pine bark amended with DL and MF, pore-water OP-P and total P concentrations, measured approximately weekly, were reduced by, on average, 64% and 58%, respectively. Total dry weight values of plants grown with DL plus MF or MF-only were 40% higher than those grown with no amendments; however, tissue P amounts and relative P uptake efficiency were the same among plants in these three treatments. Therefore, sorption of OP-P by DL and MF reduced water-extractable OP-P but did not limit P uptake by plants.Ph. D.
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Boithias, Laurie. "Modélisation des transferts de pesticides à l'échelle des bassins versants en période de crue." Phd thesis, Toulouse, INPT, 2012. http://oatao.univ-toulouse.fr/6988/1/boithias_partie_1_sur_2.pdf.
Повний текст джерелаАнотація:
Les concentrations élevées en pesticides dans les eaux de surface drainant des bassins versants agricoles sont devenues une préoccupation majeure en Europe depuis une cinquantaine d'années. Les pesticides sont transférés dans l'environnement par différentes voies (le ruissellement de surface et de sub-surface, le flux de nappe), soit en solution soit adsorbés aux particules de sol en suspension dans l'eau. Les eaux de ruissellement et de percolation entraînent avec elles des charges de contaminants dont les concentrations en solution peuvent s'avérer toxiques pour la faune et la flore aquatique et rendre l'eau impropre à la consommation humaine si le réseau de drainage est une source de captage pour l'alimentation en eau potable. Les crues constituent donc des événements hydrologiques de première importance dans la contamination des eaux continentales par les pesticides. Les objectifs de cette thèse ont été de (1) caractériser, à l'aide d'un modèle agro-hydrologique, la dynamique des transferts de pesticides à l'échelle du bassin versant dans une région agricole, notamment en période de crue ; (2) identifier les facteurs de contrôle du transfert de pesticides et (3) améliorer, le cas échéant, les équations formalisées dans le modèle. Deux approches ont été menées de front afin de répondre aux questions posées : l'analyse de données mesurées et modélisées sur le bassin versant agricole de la Save (sud-ouest de la France). Une étude de faisabilité réalisée en préliminaire a montré que le modèle Soil and Water Assessment Tool (SWAT - Arnold et al., 1998) était adapté à la modélisation du transfert de pesticides, dans les phases dissoute et particulaire, à l'échelle du bassin versant. L'hydrologie et les concentrations à l'exutoire des phases dissoute et particulaire (respectivement les nitrates et les matières en suspension) ont été calibrées. Les voies privilégiées de transfert des pesticides en fonction des conditions hydrologiques ont été identifiées. La modélisation a ensuite été mise en œuvre avec des itinéraires techniques plus détaillés en entrée du modèle et des mesures sub-journalières de pesticides en crue. Les différentes voies de transfert des pesticides dans les deux phases, ainsi que leurs facteurs de contrôle environnementaux, ont été étudiés. Deux facteurs de contrôle, respectivement dépendant des pratiques agricoles (la date d'application des pesticides, qui est un facteur anthropique) et intrinsèque aux molécules de pesticides (le coefficient Kd de partition entre phases dissoute et particulaire, qui est un facteur physico-chimique) ont été abordés plus en détail. Le rôle de la typologie du bassin versant sur les transferts est discuté. Des cartes de risque de contamination des eaux de surface par les pesticides sont présentées pour le bassin de la Save. Dans la perspective d'améliorer le formalisme des modèles de transfert des pesticides, une équation qui relie le coefficient Kd au coefficient de distribution octanol/eau Kow et à la concentration en matières en suspension a été proposée.
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Hoare, Ana Maria. "From Source to Sink: An Isotopic Perspective on the Biogeochemical Relationship between the Everglades and Florida Bay." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3151.
Повний текст джерелаАнотація:
Increasing human populations and activities in coastal areas have led to high nutrient loading and estuarine ecosystem decline. Natural hydrological patterns in South Florida have been drastically altered by changes in water management and land use practices. As a result Florida Bay has experienced a series of negative ecosystem effects including hypersalinity events, degradation of water quality, and harmful algal blooms and declines in upper trophic level populations. To remediate ecosystem decline in Florida's coastal ecosystems, the Comprehensive Everglades Restoration Plan proposes to restore a more natural hydrologic flow in the Everglades. It is expected hydrologic restoration efforts will change the amount, sources and ratios of dissolved nutrients (organic and inorganic) delivered to the bay potentially inducing an ecosystem response of changing structure and function in both planktic and benthic habitats.
Identifying biogeochemical linkages between external nutrient inputs from the Everglades and internal cycling processes of Florida Bay is critical to understanding the effects of hydrological restoration and changing nutrient regimes on Florida Bay. A nitrogen (δ15N) and carbon (δ13C ) stable isotopic approach affords an effective means of assessing the fate of varying nutrient sources and delineating the dominant biogeochemical processes governing nutrient cycling in the bay. This study's main goals were to use stable isotopic analyses of C and N in dissolved and particulate materials to determine spatial and seasonal relationships between Everglades nutrient sources and their biological sinks in Florida Bay, examine the biogeochemical relationships among inorganic and organic components of the water column and benthos in Florida Bay, and assess future ecological response to changing nutrient inputs resulting from restoration efforts.
A large east to west gradient from more enriched to more depleted δ15N values was noted in both dissolved nitrogen pools and organic components of the bay. This trend indicates that there are differing nutrient sources and biogeochemical processes influencing the various regions of the bay. Isotopic similarity of the dissolved nitrogen pools from the Everglades and particulate organic matter in the bay points to a strong relationship between both ecosystems. Everglades nutrient inputs delivered to the bay in the wet season directly influence ecological responses in the bay, in some cases increases in algal biomass. Seasonality also influences nitrogen transformations in the dissolved nitrogen pools and the sediments. During dry periods when there is little or no hydrologic flow from the Everglades into the bay, denitrification is a major process affecting nitrogen cycling in the eastern and central regions of the bay. During the wet periods, denitrification becomes suppressed and dissimilatory nitrate reduction (DNRA) is favored. Increased hydrologic flow brings fresh organic matter that fuels DNRA. There was a consistent spatial pattern from more depleted to more enriched δ13C values, onshore to offshore relative to the mainland which indicates strong terrestrial influence on Florida Bay sites along the mangrove boundary with the Everglades. Particulate organic matter exhibited a shift to more enriched δ13C values during the wet season which reflects an increase in algal biomass. A shift to more depleted δ13C values of DOM indicated increased terrestrial influence from the Everglades during the wet season.
The approach undertaken in this study identifies a strong linkage between nutrient inputs from the Everglades and biogeochemical processes in the bay. These findings underscore the need to consider the impact of both allochtonous nutrient inputs and the dominant processes governing cycling in the bay when making management decisions that continue to refine hydrologic restoration plans.
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Cotte, Laura. "Devenir des éléments métalliques en milieu hydrothermal profond : partition dissous-particulaire effective et spéciation dans le mélange fluide hydrothermal-eau de mer précoce." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0116/document.
Повний текст джерелаАнотація:
Quarante ans après la découverte de la circulation hydrothermale profonde, les processus chimiques se produisant dans le mélange entre le fluide hydrothermal et l’eau de mer restent mal contraints. Ce travail de thèse, dont l’originalité repose sur l’utilisation systématique de la filtration in situ, présente le partitionnement effectif des éléments métalliques majeurs (principalement Fe, Cu, Zn, Ba et Ca) entre les phases dissoutes (< 0,45 μm) et particulaire (> 0,45 μm) dans le mélange précoce-intermédiaire de plusieurs fumeurs du champ hydrothermal Lucky Strike (37°N, MAR). Le comportement et la spéciation du Cu dans la fraction dissoute sont ensuite explorés plus en détail par le biais de compétitions de ligands et de mesures voltamétriques. Nos résultats démontrent en premier lieu l’importance de la filtration in situ pour s’affranchir des biais induits par le prolongement des réactions de précipitation ou de redissolution pouvant se produire lors de la remontée des échantillons. L’examen des fluides collectés à différentes reprises et sur une large panoplie de fumeurs (240 échantillons) démontre une variabilité spatiale des signatures chimiques le long de l'axe est-ouest du champ hydrothermal. Parmi les métaux étudiés, Fe, Ca et Ba sont principalement mesurés sous forme dissoute tandis que Cu et Zn sont majoritairement particulaires. Dans le mélange initital (50‒150°C, dMn > 50 μM), le pool de particules est dominé par de la sphalérite (ou wurtzite) et de la chalcopyrite, avec généralement moins de pyrite. Dans cette zone, les changements chimiques semblent cinétiquement limités et les fluides échantillonnés présentent une signature chimique proche de celle du fluide pur. Cependant, à mesure que le fluide hydrothermal se mélange à l'eau de mer (4‒50°C, dMn < 50 μm), le partitionnement de certains métaux alcalins et alcalinoterreux (Ca, Ba, Mg et Sr) entre les deux phases est profondément affecté par la précipitation de sulfates. Contrairement aux prédictions thermodynamiques, la précipitation d’anhydrite, de barite et potentiellement de caminite est observée dans la partie relativement froide du mélange (4-50°C). L’augmentation importante du pH dans cette zone conduit également à l’initiation de la précipitation d’oxydes de Fe. Enfin, dans la phase dissoute, les ligands du Cu semblent être principalement des sulfures inorganiques issus du fluide hydrothermalForty years after the discovery of deep hydrothermal circulation, chemical processes occurring in the early mixing between hydrothermal vent fluids and deep seawater are still not fully constrained. This thesis, whose the originality lies on the systematic use of in situ filtration, report on the partitioning of major metals (mainly Fe, Cu, Zn, Ba and Ca) between the dissolved (< 0.45 μm) and particulate (> 0.45 μm) phases in the early mixing of several black and clear smokers from the Lucky Strike vent field (37°N, MAR). The behavior and the speciation of Cu in the dissolved fraction are then deeper explored by performing ligands competition and voltammetric measurements. Our results first demonstrate the importance of the in situ filtration to restrict the bias induced by precipitation reactions or particles redissolution potentially occurring postsampling.The examination of the fluids collected at several occasions and on a wide range of smokers (240 samples) shows a spatial variability of chemical signatures along the east-west axis of the hydrothermal field. Among metals studied, most of Fe, Ca and Ba are measured as dissolved species whereas Cu and Zn are mainly found as particles. In the initial part of the mixing (50-150°C, dMn > 50 μM), the particulate pool is dominated by sphalerite (or wurtzite) and chalcopyrite, with generally lower amount of pyrite. In this zone, chemical changes seem kinetically limited and fluids collected display a chemical signature close to that of the end-members. However, as the hydrothermal fluid progressively mixes with seawater (4-50°C, dMn < 50 μm), the partitioning of some alkali and alkaline earth metals (Ca, Ba, Mg and Sr) between the two phases is deeply affected by precipitation of sulfates. Unlike thermodynamic predictions, precipitation of anhydrite, barite and potentially caminite is observed in the colder part of the mixing (4-50°C). The large increase of pH in this area also drives the beginning of Fe oxides precipitation. Finally, the dissolved Cu-ligands detected seem to be mainly inorganic sulfides originating from the hydrothermal fluid
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Lanceleur, Laurent. "L’argent : sources, transfert et bioaccumulation : cas du système fluvio-estuarien girondin." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14270/document.
Повний текст джерелаАнотація:
Les rejets d’argent (Ag) dans l’environnement liés à l’exploitation minière aux diverses applications industrielles (e.g. bijouterie, médecine, photographie, électronique et plus récemment les nanotechnologies) font de Ag un polluant historique et émergent, dont les transferts et les effets dans les milieux aquatiques sont largement sous-documentés. Ce travail présente un premier bilan des sources, du transfert et de la bioaccumulation de Ag dans le système fluvio-estuarien de la Gironde. Le continuum Lot-Garonne-Gironde, connu pour une pollution polymétallique (e.g. Cd, Zn) provenant du bassin de Decazeville, est un système modèle pour l’étude des transferts métalliques du continent à l’océan. Les enregistrements des signaux historiques (~50 ans) de Ag dans les sédiments du Lot en amont (Ag : 0,3 mg/kg) et en aval (Ag : jusqu’à 7 mg/kg) du bassin de Decazeville sont similaires à ceux de Cd, indiquant des sources et des processus de transport/dépôt communs liés à l’histoire minière et industrielle jusqu’en 1986. Le lessivage et l’érosion actuels des terrils provoquent localement des concentrations en Ag particulaire (AgP : 260 mg/kg) et dissous (AgD : 1260 ng/l) dans la rivière Riou-Mort qui sont 2 à 3 ordres de grandeur supérieures aux valeurs typiques. Malgré ces fortes concentrations, la contribution du Riou-Mort aux flux de Ag de la Garonne (AgD : 0,008 à 0,041 t/an ; AgP : 0,306 à 2,44 t/an ; 1999-2009) reste faible (AgP : <11% ; AgD : <6%). La Garonne transporte l’essentiel (63-83%) des apports en Ag à l’estuaire principalement sous forme particulaire (96±2%). La détermination du bruit de fond géochimique régional (AgP/ThP=0,026) a permis d’évaluer (i) la contribution naturelle (20% à 65%) aux flux totaux en AgP et (ii) les flux anthropiques spécifiques de AgP (15±10 g/km²/an et 0,24±0,16 g/hab/an) à l’échelle du bassin versant de la Garonne (La Réole). Dans l’estuaire salin, la désorption par les ions chlorures libère ~60% de AgP vers la colonne d’eau (addition), provoquant des concentrations maximales en AgD (6-8 ng/l) à salinité 15-25. La fraction en Ag désorbé correspond à la fraction potentiellement biodisponible ou réactive (i.e. extractible par HCl 1 M). Ainsi, les premières estimations des flux nets indiquent que l’export annuel de Ag vers le domaine côtier est à 50-80% lié à la phase dissoute (0,64 à 0,89 t/an en 2008 et 0,56 à 0,77 t/an en 2009). Bien que plus biodisponible sous forme ionique Ag+ (dominante en eau douce), l’accumulation de Ag dans les organismes estuariens (huîtres, crevettes et anguilles) reflète la pression d’exposition supérieure en eau saumâtre. L’exposition in situ d’anguilles européennes, espèce recommandée pour la biosurveillance du milieu dans le cadre de la Directive Cadre sur l’Eau, dans des cages à différents sites clé de l’estuaire pendant 3 mois, a mis en évidence les voies directes et trophiques de la contamination en Ag à des niveaux de contamination environnementaux. L’enregistrement historique de la contamination en Ag des huîtres de la Gironde (1979-2007, RNO, Ifremer) indique que le bassin de Decazeville a été la source majoritaire en Ag jusqu’en ~1988. Cependant, l’accumulation maximale de Ag dans ces bivalves après 1993 (de ~40 à plus de 100 mg/kg, poids sec) révèle une contribution croissante de sources additionnelles et contemporaines en Ag comme la photographie, l’ensemencement des nuages (30 à 63 kg/an) ou encore les rejets des eaux usées urbaines de Toulouse et de Bordeaux (42 et 57 kg/an). Ce travail constitue une base nécessaire à l’étude des rejets du cycle de Ag (y compris les nanoparticules) dans le milieu aquatique (quantification, transfert et toxicité) et des risques associésSilver (Ag) emissions into the environment from former mining activities and various industrial applications (e.g. jewellery, medicine, photography, electronic products and more recently nanotechnology) make Ag both a historic and an emergent pollutant for which information on its transfer and toxicity in aquatic system are scarce. This work provides a first assessment of Ag sources, transfer and bioaccumulation in the Gironde fluvial-estuarine system. The Lot-Garonne-Gironde River continuum, known for its polymetallic pollution (e.g. Cd, Zn) derived from the Decazeville basin, is a model system for studies on metal transfer from watersheds to the ocean. The relationship between historical records (~50 years) of Ag concentrations in sediment cores from the Lot River, upstream (Ag: 0.3 mg/kg) and downstream (Ag: up to 7 mg/kg) of the Decazeville basin and those of Cd constitutes evidence of a common source and transport/settlement processes due to industrial activities until 1986. High particulate Ag (AgP: 260 mg/kg) and dissolved Ag (AgD: 1,260 ng/l) concentrations in the Riou-Mort River were attributed to current leaching and erosion of slag heaps by rainwater. Those concentrations were 2 to 3 orders of magnitude greater than typical values in the Gironde watershed. However, the Riou-Mort River contribution to the Garonne River Ag fluxes (AgD: 0.008-0.041 t/a; AgP: 0.306-2.44 t/an; 1999-2009) remained low (AgP: <11%; AgD: <6%). The Garonne River provided the quasi totality (63-83%) of Ag inputs to the estuary, mainly in its particulate form (96±2%). The regional geochemical background (AgP/ThP=0.026) was useful to estimate (i) the natural contribution (20-65%) to total AgP fluxes and (ii) the anthropogenic specific fluxes of AgP (15±10 g/km²/a and 0.24±0.16 g/hab/a) in the Garonne watershed (La Réole). In the estuarine salinity, chloro-complexation desorbed ~60% of AgP, causing maximalum AgD concentrations (6-8 ng/l) at salinity 15-25 (addition to the dissolved phase). This quantity was similar to the potentially bioavailable or reactive fraction (i.e. extracted by HCl 1 M). The first estimations of net fluxes suggested that 50-80% of the Ag annual export to the coast occurred in the dissolved phase (0.64-0.89 t/a in 2008 and 0.56-0.77 t/a in 2009). Even if the ionic form Ag+ (the main form in freshwater) is considered as the most bioavailable form, Ag accumulation in estuarine organisms (oysters, shrimps and eels) reflected the higher exposition pressure in brackish water. In-situ caging of European Eels (recommended species for the biosurvey of aquatic systems; European Water Framework Directive) in key sites of the Gironde Estuary during 3 months, highlighted the direct and trophic pathways of Ag contamination at the environmental level. The historical record of Ag contamination of the Gironde Estuary oysters (1979-2007, French Mussel Watch, RNO) indicated that the Decazeville basin was a major Ag source until ~1988. However, the maximum Ag accumulation in oysters after 1993 (from ~40 to more than 100 mg/kg, dry weight) suggested an increasing contribution of additional and contemporary Ag sources like photography, cloud seeding (30-63 kg/a) or Toulouse and Bordeaux wastewater effluents (42-57 kg/a). This work is a basis for future work on Ag (including nanoparticles) cycles and related risks in aquatic systems (quantification, transfer and toxicity)
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Harvey, Therese. "Bio-optics, satellite remote sensing and Baltic Sea ecosystems : Applications for monitoring and management." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-119578.
Повний текст джерелаАнотація:
Earth observation satellites cover large areas with frequent temporal repetition and provide us with new insight into ocean and coastal processes. Ocean colour measurements from satellite remote sensing are linked to the bio-optics, which refers to the light interactions with living organisms and dissolved and suspended constituents in the aquatic environment. Human pressures have changed the aquatic ecosystems, by, for example, the increased input of nutrient and organic matter leading to eutrophication. This thesis aims to study and develop the link between bio-optical data and the remote sensing method to the monitoring and management of the Baltic Sea. The results are applied to the European Union’s Water Directives, and the Baltic Sea Action Plan from the Helsinki commission. In paper I indicators for eutrophication, chlorophyll-a concentration and Secchi depth were evaluated as a link to remote sensing observations. Chlorophyll-a measurements from an operational satellite service (paper I) were compared to conventional ship-based monitoring in paper II and showed high correlations to the in situ data. The results in paper I, II and IV show that the use of remote sensing can improve both the spatial and temporal monitoring of water quality. The number of observations increased when also using satellite data, thus facilitating the assessment of the ecological and environmental status within the European Union’s water directives. The spatial patterns make it possible to study the changes of e.g. algae blooms and terrestrial input on larger scales. Furthermore, the water quality products from satellites can offer a more holistic and easily accessible view of the information to decision makers and end-users. In paper III variable relationships between in situ bio-optical parameters, such as coloured dissolved organic matter (CDOM), dissolved organic carbon, salinity and Secchi depth, were found in different parts of the Baltic Sea. In paper IV an in situ empirical model to retrieve suspended particulate matter (SPM) from turbidity was developed and applied to remote sensing data. The use of Secchi depth as an indicator for eutrophication linked to the concentrations of chlorophyll-a and SPM and CDOM absorption was investigated in paper V. The variations in Secchi depth were affected differently by the mentioned parameters in the different regions. Therefore, one must also consider those when evaluating changes in Secchi depth and for setting target levels for water bodies. This thesis shows good examples on the benefits of incorporating bio-optical and remote sensing data to a higher extent within monitoring and management of the Baltic Sea.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.
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Ordou, Niloofar. "Investigation of Physiochemical Properties of Size-resolved Biomass Burning/Local Wildfire Aerosols." Thesis, Griffith University, 2021. http://hdl.handle.net/10072/410471.
Повний текст джерелаАнотація:
Overall, particulate matter (PM) and household air pollution are at the root of 2.9 million deaths annually. One of the sources of particulate matter is biomass burning (BB) smoke. These particles can be formed by natural fires, prescribe agriculture fires, and as a result of burning fuel for cooking and heating houses. BB smoke particles can have various health effect and environmental impacts depending on a number of factors. Altering ozone refraction, they can act as cloud condensation nuclei. Health risks associated with these particle have been studied for long. Pulmonary, heart, carcinogen (especially due to compounds like Poly Aromatic Hydrocarbons (PAH).
First and foremost, the nature of the fuel has a direct impact on the composition of the particulate matter and gaseous particles formed as the combustion products. Woody, Grass, or leafy fuels have been found to be composed of different compounds with different mass fractions. For example, cellulose content in wood is higher than other types of biomass fuel. As a results, it is logical to seek similar compound ending up in the particulate matter. The scale and intensity of the fire is the other influential factor. Although the effect of natural wildfire (bushfire) smoke particles would not be as direct and immediate as those evolving from the fuel burnt in household uses, long term effect of exposure to these particles spreading within the atmosphere month and even years after the fire has happened should not be overlooked. Besides, in very close vicinities to the fires, in fresh smoke less than minutes old, there always exist high number of finer particles which are health-wise of more concern compared to larger particle (as these finer particles penetrate into lower parts of the respiratory system through diffusion). Weather conditions, like elevation, wind speed, humidity, and sunlight are also influential factors in the formation of these particles. The other crucial factor is the phase of burning, i.e. Ignition, flaming, mixed state, and smouldering. Numerous studies have investigated the effect of these conditions on the size distribution, number concentration and physiochemical properties of smoke particles.
PM properties of BB smoke have been investigated all around the globe for different biomass types and different burning conditions. Black carbon (BC) and organic carbon (OC) content of the PM are the most documented investigated items as they contributes to the high mass percentage of the PM. Other ubiquitous PM components include anhydrosugars, alcohols, PAHs, acids, water soluble ions, and trace elements. Gaseous particles resulted from BB carry with them sulphur oxides (SOx) and nitrogen oxides (NOx), volatile and semi volatile organic compounds. Each of these compounds and materials are known to have serious health and climate impacts.
Numerous studies have used different devices and technologies to investigate the effect of fuel type and amount, and phase of burning and operational mode on different properties of fresh and aged smokes in case of small scale controlled or laboratory burns, massive natural wildfires, or air-forced cook stove gasifiers.
In Australia, despite contributing to more than 7% of biomass burning emissions annually, there are quite a few exhaustive studies on the properties of bushfire particles. The importance of research redoubles considering the mega-fires taking place in Australia 2019-2020 which ravaged an estimate of 19 million hectares. This study is aimed to make a contribution in filling this gap and finding novel ideas in order to investigate different factors influencing Australian local vegetation fires which could potentially effect the environment and human health. Three journal articles are published based on this study, parts of which are used in different sections throughout this report. Citations are made in the beginning of the main relevant chapters. Abstract summaries are presented briefly here: First paper: Under controlled laboratory settings and small scale fires of vegetation collected from Toohey forest, it was found that leaves classification burn with flaming dominant phases producing intense black smoke which is consisted of larger particles as opposed to more smouldering-dominant burning of the branch and grass classifications releasing white smoke emissions which contain finer particles. Elemental analysis detected nine main elements in all three classifications and in three size fractions of smoke particulate matter samples (from 14.1μm to below 2.5μm). Potassium, a biomarker, was the most prevalent element among the samples followed by sulphur. Less abundant elements were found to be Na, Al, Mg, Zn, Si, Ca, and Fe.
Second paper: Particle size distribution in biomass smoke was observed for different burning phases, including flaming and smouldering, during the combustion of nine common South Queensland Australian vegetation representatives. Smoke particles generated during smouldering phase of combustions were found to be coarser as compared to flaming aerosols for all hard species. In contrast, for leafy species this trend was inversed. In addition, the combustion process was investigated over the entire duration of burning by acquiring every second data for all nine species. Particles were separately characterised in two categories: fine particles (diameter below 200nm), and course particles with the diameter larger than 200nm. It was found that fine particles contribute to more than 90 percent of the total fresh smoke particles for all investigated species.
Third paper: smoke samples were collected during prescribed fire burns conducted between May 2018 and August 2019across different regions in Toohey forest, Queensland, Australia. Particle size/mass distribution as well as size-segregated elemental content were measured and the results were compared against the values obtained from the combustion of similar vegetation mixture under controlled laboratory settings. It was found that the concentration levels of coarse particles (sizes above 1 μm) were higher during field burn events, whereas the contributions of PM1 (smaller than 1 μm) was higher in case of laboratory burns. Following elemental analysis of different size classes of smoke particles (<0.96μm, 0.96-2.5μm, and >2.5μm) confirmed the presence of eight elements in both laboratory and field cases (Na, K, Mg, Ca, Zn, Al, Fe, S), however, levels of Ca, Mg, Al, and S were noticeably higher in prescribed fire results. Observed discrepancies between field and laboratory data could be attributed to the effect of top soil and duff layers present in prescribed fires/natural wildfires and absence thereof in the laboratory burns, which reveals the influential role of the aforementioned layers on the overall air quality status across bushfires-affected areas.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Estrela, Sílvia Regina Marques Faria. "Wildfire effects on forest soil organic matter stocks and losses by runoff." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/19151.
Повний текст джерелаАнотація:
Doutoramento em Ciências e Engenharia do AmbienteO solo é considerado o maior reservatório de carbono (C) global e, um importante sumidouro de CO2 atmosférico. Os incêndios florestais são um fenómeno frequente nos ecossistemas mediterrânicos, em especial em Portugal. Nas últimas décadas verificou-se um aumento do número de incêndios e os cenários de alterações climáticas sugerem que os regimes de incêndios se poderão intensificar no futuro. Os incêndios florestais podem provocar efeitos importantes a curto e médio prazo em fatores chave da qualidade do solo, tais como a quantidade e qualidade da matéria orgânica (SOM). Devido à grande quantidade de carbono (C) armazenado no solo, mesmo pequenas mudanças na SOM poderão ter um efeito significativo sobre os ciclos biogeoquímicos e, consequentemente, sobre o clima global. Embora existam vários estudos que documentam os efeitos pós-fogo sobre os processos hidrológicos e de erosão, em termos de impactos sobre a quantidade (em termos de stocks e perdas de carbono orgânico (OC) por escorrência superficial), qualidade da SOM e sedimentos exportados, bem como a sua recuperação pós-fogo tem sido pouco estudados. Estes foram os principais objetivos deste estudo, realizado em plantações de eucalipto (Eucalyptus globulus), um dos tipos de vegetação florestal mais suscetíveis ao fogo no centro-norte de Portugal. O efeito dos incêndios florestais na qualidade da SOM do solo foi avaliado na camada superficial do solo (0-2 cm) em 4 períodos de amostragem, imediatamente antes das primeiras chuvas até dois anos após o incêndio. Para tal, foram utilizadas várias técnicas analíticas, tais como a deteção e caraterização de biomarcadores lipídicos por cromatografia gasosa/espetrometria de massa (GC-MS), caraterização de SOM por pirólise acoplada à cromatografia gasosa e à espetrometria de massa (Py-GC/MS) e, por ressonância magnética nuclear 13C de estado sólido (13C NMR). As exportações pós-fogo de OC por escorrência superficial e as respetivas contribuições das frações de carbono orgânico dissolvido (DOC), carbono orgânico particulado (POC) e carbono inorgânico dissolvido (DIC) foram também determinados em amostras de escorrência superficial recolhidas em intervalos de 1 a 2 semanas ao longo do primeiro ano após o incêndio. Os resultados mostraram que o incêndio provocou mudanças consideráveis na quantidade e qualidade da SOM. Estas incluíram a degradação térmica e quebra de compostos de n-alquilo. Aumentaram os rácios das cadeias curto-longo de n-alcanos e das cadeias de n- FAMEs, assim como a alteração dos respetivos índices. Além disso, a abundância relativa de certos biomarcadores específicos de determinadas plantas foram modificados, especialmente diminuição de terpenóides, tais como epiglobulol, ledol e globulol que são característicos do Eucalyptus globulus. Outras diferenças observadas no solo queimado foram a presença de levoglucosano, um marcador típico para a alteração térmica de polissacarídeos, maior abundância relativa de compostos derivados da lenhina (vanilina e metoxifenol) e a presença de estruturas de N-heteroaromáticos. Os espetros de 13C NMR também indicaram que o fogo produziu um aumento considerável na aromaticidade e condensação aromática da SOM. Estas diferenças verificaram-se durante o período de estudo, sugerindo uma lenta recuperação das propriedades do solo, possivelmente influenciadas, quer por uma recuperação limitada da vegetação, quer pela intensificação das perda de solo após o incêndio. O presente trabalho abordou também um tema pouco estudado como são os efeitos pós-fogo nas perdas de OC no solo por escorrência superficial. Os principais resultados apontaram para (i) uma maior quantidades de cinzas na encosta orientada a norte do que na encosta orientada a sul, enquanto que para a quantidade total de carbono orgânico (TOC) nas cinzas, estas não apresentaram diferenças; (ii) quer a perda total de sedimentos, quer a quantidade TOC do solo apresentouse maior na encosta orientada a norte do que a sul; (iii) a fração de OC que apresentou as maiores perdas, para ambas as encostas, foi a particulada. A quantificação das perdas de OC pós-fogo podem contribuir de forma relevante para a proteção dos ecossistemas, nomeadamente em termos da fertilidade do solo.
Soil is considered the largest carbon reservoir and an important global sink for atmospheric CO2. Wildfires are frequent in Mediterranean ecosystems, especially in Portugal. In recent decades there has been an increase in the number of fires and climate change scenarios suggest that the fire regimes are likely to increase in the future. Forest fires can have important short−to long−term implications for key aspects of soil quality, such as the quantity and quality of soil organic matter (SOM). Due to high amount of carbon (C) stored in soil, even slight alterations of SOM can affect significantly biogeochemical cycles, hence, affecting the whole global climate. Although numerous studies have documented the effects of wildfires on hydrological and erosion processes, the effects of fire on the quantity (in terms of stocks and losses of OC content by overland flow) and quality of SOM and in the sediments eroded, as well on postfire SOM recovery, have received considerably less research attention. These were the principal goals of the present study conducted on eucalypt plantations, one of the most fire-prone forest types in northcentral Portugal. The effects of wildfires on quality of SOM was evaluated in topsoil samples (0-2 cm) on four sampling occasions, starting immediately after the first post-fire rain till two years later. It was necessary a combination of multi-analytical techniques, such as lipid-biomarker analysis by gas chromatography-mass spectrometry (GC-MS), SOM characterization by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and solid state 13C nuclear magnetic resonance (13C NMR) spectroscopy. Post-fire OC exports by overland flow and the contributions of the dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) fractions were measured in runoff samples collected at 1- to 2- weekly intervals during the first year after the wildfire. The results showed that wildfire produced substantial changes in the quantity and quality of SOM. These included the thermal breakdown and cracking of n-alkyl compounds. Ratios of short-to-long n-alkanes and n-fatty acid methyl esters (FAMEs) increased and typical carbon number predominance indexes for n-alkanes (odd-to-even) and n-FAMEs (evento- odd) were altered. Furthermore, the relative abundances of certain markers, which are plantspecies specific were modified, especially by decreasing terpenoids such as epiglobulol, ledol and globulol, which are characteristic of Eucalyptus globulus. Other differences observed in the burnt soil were the appearance of levoglucosan, a typical marker for the thermal alteration of polysaccharides, larger relative abundances of lignin-derived compounds (vanillin and methoxyphenols) and the presence of N-heteroaromatic structures. The 13C NMR spectra also indicated that the wildfire produced a considerable increase in the aromaticity and aromatic condensation of the topsoil SOM. The continuation of these differences in SOM quality during the period of this study, suggested a slow recovery of soil properties, possibly influenced by a limited recovery of the vegetation after the fire combined with the fire-enhanced losses of soil. The present work also evaluated post-fire soil OC losses by overland flow in recently two burnt eucalypt plantations, addressing a topic that has seldom been investigated. The main findings were that: (i) the amount of deposited ashes was higher at the NW slope than at the SE slope, while ashes total organic carbon (TOC) content revealed no differences; (ii) total sediment losses and also the TOC export were higher at the NW slope than at the SE slope; (iii) particulate organic carbon fraction showed the highest loss at the both topsoil sites. In addition, this study provides some insight into post-fire organic carbon losses in the recently burnt areas, which is crucial information for ecosystem management, especially in terms of soil fertility.
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Sabetraftar, Karim, and Karim Sabetraftar@anu edu au. "The hydrological flux of organic carbon at the catchment scale: a case study in the Cotter River catchment, Australia." The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20070502.141450.
Повний текст джерелаАнотація:
Existing terrestrial carbon accounting models have mainly investigated atmosphere-vegetationsoil
stocks and fluxes but have largely ignored the hydrological flux of organic carbon. It is
generally assumed that biomass and soil carbon are the only relevant pools in a landscape
ecosystem. However, recent findings have suggested that significant amounts of organic carbon
can dissolve (dissolved organic carbon or DOC) or particulate (particulate organic carbon or
POC) in water and enter the hydrological flux at the catchment scale. A significant quantity of
total organic carbon (TOC) sequestered through photosynthesis may be exported from the
landscape through the hydrological flux and stored in downstream stocks.¶
This thesis presents a catchment-scale case study investigation into the export of organic carbon
through a river system in comparison with carbon that is produced by vegetation through
photosynthesis. The Cotter River Catchment was selected as the case study. It is a forested
catchment that experienced a major wildfire event in January 2003. The approach is based on an
integration of a number of models. The main input data were time series of in-stream carbon
measurements and remotely sensed vegetation greenness. The application of models to
investigate diffuse chemical substances has dramatically increased in the past few years because
of the significant role of hydrology in controlling ecosystem exchange. The research firstly
discusses the use of a hydrological simulation model (IHACRES) to analyse organic carbon
samples from stream and tributaries in the Cotter River Catchment case study. The IHACRES
rainfall-runoff model and a regionalization method are used to estimate stream-flow for the 75
sub-catchments. The simulated streamflow data were used to calculate organic carbon loads
from concentrations sampled at five locations in the catchment.¶
The gross primary productivity (GPP) of the vegetation cover in the catchment was estimated
using a radiation use efficiency (RUE) model driven by MODIS TERRA data on vegetation
greenness and modeled surface irradiance (RS). The relationship between total organic carbon
discharged in-stream and total carbon uptake by plants was assessed using a cross-correlation
analysis.¶
The IHACRES rainfall-runoff model was successfully calibrated at three gauged sites and
performed well. The results of the calibration procedure were used in the regionalization method
that enabled streamflow to be estimated at ungauged locations including the seven sampling
sites and the 75 sub-catchment areas. The IHACRES modelling approach was found appropriate
for investigating a wide range of issues related to the hydrological export of organic carbon at
the catchment scale. A weekly sampling program was implemented to provide estimates of
TOC, DOC and POC concentrations in the Cotter River Catchment between July 2003 and June
2004. The organic carbon load was estimated using an averaging method.¶
The rate of photosynthesis by vegetation (GPP) was successfully estimated using the radiation
use efficiency model to discern general patterns of vegetation productivity at sub-catchment
scales. This analysis required detailed spatial resolution of the GPP across the entire catchment
area (comprising 75 sub-catchment areas) in addition to the sampling locations. Important
factors that varied at the catchment scale during the sampling period July 2003 June 2004,
particularly the wildfire impacts, were also considered in this assessment.
¶
The results of the hydrologic modelling approach and terrestrial GPP outcome were compared
using cross correlation and regression analysis. This comparison revealed the likely proportion
of catchment GPP that contributes to in-stream hydrological flux of organic carbon. TOC Load
was 0.45% of GPP and 22.5 - 25% of litter layer. As a result of this investigation and giving due
consideration to the uncertainties in the approach, it can be concluded that the hydrological flux
of organic carbon in a forested catchment is a function of gross primary productivity.
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Chu, Housen. "Response and Biophysical Regulation of Carbon Fluxes to Climate Variability and Anomaly in Contrasting Ecosystems." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1418393261.
Повний текст джерела
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Ahlström, Matilda. "Undersökning av turbiditet och föroreningars sammansättning i urbana vatten." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-445502.
Повний текст джерелаАнотація:
Stormwater is water that originates from snow or rainfall and that cannot naturally infiltrate the soil. When stormwater flows from hard surfaces it can transport different pollutants to watercourses. By measuring turbidity continuously and using the relationship between turbidity and pollutants the pollutant levels can be estimated. The aim of this study was partly to investigate the relationship between turbidity and phosphorus, metals and PAHs in stormwater in three catchment areas. This study also aimed to investigate how the distribution between dissolved and particulate bound concentrations of phosphorus and metals varied during different rain courses and at different catchment areas. The study was carried out in Uppsala and included continuous measurement of turbidity in three stormwater wells in three catchment areas. Seven samples were also taken at different precipitation occasions in both stormwater and in Fyrisån. In Svartbäcken there was a strong relationship between turbidity and phosphorus and metals. In Librobäck there was an indication that there was a strong relationship between turbidity and some metals and PAH:s. There was no relationship between turbidity and pollutants in Luthagen. Based on these samples, it is difficult to draw any conclusions about why the connections differed for certain pollutants and catchment areas. Due to the fact that the number of measuring points was too few the continuous measurement could not be used to estimate variations in pollution levels. To be able to use the continuous measurement, a longer sampling period and different precipitation occasions is needed. The continuous measurements were used to get an idea of when the samples were taken during the stormwater flow. The results also showed that all pollutants were mostly particulate bound for samples taken at the beginning of a precipitation occasion and with some precipitation during the sampling. For samples that did not take place in connection with stormwater runoff events, the distribution varied for the pollutants in the study. It has not been possible to see a clear trend for how the distribution between dissolved and particulate bound pollutants has varied between different catchment areas.Dagvatten är vatten som uppkommer vid regn eller vid snösmältning och som inte kan infiltrera naturligt i marken. När dagvattnet avrinner ytligt på marken kan det föra med sig föroreningar till recipienten. Genom att mäta turbiditet kontinuerligt och utnyttja eventuella samband med föroreningar kan föroreningshalter i dagvatten uppskattas. Studien hade två huvudsakliga syften varav det ena var att undersöka samband mellan turbiditet och fosfor, metaller samt PAH:er i dagvatten i tre avrinningsområden. Detta för att se om sambanden kunde användas för att med hjälp av kontinuerlig mätning av turbiditet uppskatta föroreningshalter vid avrinningsområdena. Det andra syftet var att undersöka hur fördelningen mellan lösta och partikulärt bundna andelar fosfor och metaller varierade under olika regnförlopp och vid olika avrinningsområden. Studien utfördes i Uppsala och innefattade delvis kontinuerlig mätning av turbiditet i tre dagvattenbrunnar i tre avrinningsområden. Det gjordes även sju stickprovtagningar vid olika nederbördstillfällen i både dagvatten och i Fyrisån. I Svartbäcken visade resultaten att det fanns starka samband mellan turbiditet och fosfor och metaller. I Librobäck fanns det en indikation för starka samband mellan turbiditet och fosfor samt vissa metaller och PAH:er. I Luthagen fanns det dock inga samband mellan turbiditet och undersökta föroreningarna. Utifrån dessa prover var det svårt att dra några slutsatser kring varför sambanden skilde sig åt för vissa föroreningar och avrinningsområden. På grund av att antalet mätpunkter var för få kunde inte den kontinuerliga mätningen användas för att uppskatta variationer av föroreningshalter. För att kunna använda den kontinuerliga mätningen behövs en längre provtagningsperiod med fler provtagningar. Resultatet visade även att den partikulärt bundna andelen dominerade för alla föroreningar vid de provtagningar som togs i början på ett nederbördstillfälle och vid viss nederbörd. Vid provtagningar som utfördes senare under nederbördstillfället varierade fördelningen för de olika föroreningarna. Det har inte varit möjligt att se en tydlig trend för hur fördelningen mellan lösta och partikulärt bundna föroreningar varierade mellan olika avrinningsområden.
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Beghoura, Houda. "Modélisation de l'impact du Fer particulaire d'origine sédimentaire sur les cycles biogéochimiques marins Air‐sea turbulent fluxes from a wave‐following platform during six experiments at sea, in JGR Oceans 124 (6), June 2019 Impact of inorganic particles of sedimentary origin on global dissolved iron and phytoplankton distribution, in JGR Oceans 124 (12), December 2019." Thesis, Brest, 2020. http://www.theses.fr/2020BRES0001.
Повний текст джерелаАнотація:
Il existe encore des incertitudes importantes concernant le cycle biogéochimique du fer, sa nature et la quantification de ses sources. Ce fer dissous (dFe) est considéré comme étant la forme la plus biodisponible ce qui a induit la sous-évaluation du rôle du fer particulaire (pFe) comme une source potentielle de dFe. Pourtant, la remise en suspension des sédiments libère davantage de pFe que de dFe. Dans ce contexte, ma thèse remet en question la vision traditionnelle du rôle du fer particulaire inorganique sédimentaire (pFeinorg) et propose la première modélisation de ce dernier comme source externe de dFe. Le modèle numérique PISCES a donc été adapté pour tenir compte d’un flux supplémentaire de fer en s’appuyant sur une climatologie de la dynamique à partir de la configuration NEMOPISCES globale à 2 degrés de résolution. Les simulations mettent en exergue la sensibilité de la biomasse phytoplanctonique à la forme de fer provenant des sédiments ; les limitations en macronutriments et celles en fer sont considérablement modifiées, ainsi que les gradients côte–large de chlorophylle. Le transport plus efficace du fer en tant que pFeinorg permet d’atteindre des régions éloignées de sa source. Son accumulation et sa dissolution dans les zones de convergences induisent via downwelling l’enrichissement de la surbsurface ; à ceci s’ajoute le processus de chute de la particule. Cependant, ces processus demeurent peu étudiés. Les tests de sensibilité ont montré que le gain (absence de chute) ou la perte (chute rapide) en fer dans l’océan, ou encore la prépondérance du pFe sur le dFe seraient modulés par le taux de dissolution. En revanche, la distribution de la chlorophylle est mieux représentée dans la mesure où les processus qui régissent la distribution du PFeinorg et du dFe qui en dérive sont, de concert, pris en compte. Une manière de mieux représenter les répercussions du fer sur les cycles biogéochimiques marins, serait de mieux contraindre les processus liés au PFeinorgThere are still substantial uncertainties in the iron biogeochemical cycle, including those related to the nature and magnitude of its external sources.Dissolved iron (dFe) is considered to be the most bioavailable form, which led to the underestimation of the role of particulate iron (pFe) as a potential source of dFe. Yet sediment resuspension releases more pFe than dFe. In this context, my thesis challenge the traditional view of the role of sedimentary inorganic particulate iron (pFeinorg) and proposes the first modeling of pFeinorg as a new external source of dFe. For this purpose, the PISCES numerical model has been adapted to take into account an additional iron flux based on a climatology of dynamics from the global NEMO-PISCES configuration at 2 degrees of resolution. Simulations highlight the sensitivity of phytoplankton biomass to the sedimentderived form of iron ; macronutrient limitations and iron limitations are considerably modified, as are coastal – open ocean chlorophyll gradients.The iron is more efficiently transported as a pFeinorg, allowing it to reach regions far from its source. Its accumulation and dissolution in the zones convergence zones would allow via downwelling to enrich the subsurface; in addition to this, the process of particle sinking. However, few studies have been conducted on these processes. Sensitivity tests have shown that the gain (no sinking velocity) or loss (relatively fast sinking velocity) of iron in the ocean or the preponderance of particulate iron over dissolved iron would be modulated by the dissolution rate. However the distribution of chlorophyll is better represented to the extent that the processes governing the distribution of pFeinorg and the dFe derived from it are jointly taken into account. One way to better represent the impact of iron on marine biogeochemical cycles would be to better constrain the processes associated with pFeinorg
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Caselles, Osorio Aracelly. "Influence of the characteristics of organic matter on the efficiency of horizontal subsurface-flow constructed wetlands." Doctoral thesis, Universitat Politècnica de Catalunya, 2007. http://hdl.handle.net/10803/7054.
Повний текст джерелаАнотація:
Los sistemas de humedales construidos de flujo subsuperficial horizontal (HCFSS) constituyen una tecnología válida para la depuración de aguas residuales urbanas. Uno de los principales objetivos de estos sistemas es eliminar la materia orgánica, los sólidos y los nutrientes presentes en el agua residual decantada. La materia orgánica mineral contenida en el agua residual se compone de una mezcla compleja de sustancias de diferentes tamaño y composición química. En sistemas de tratamiento convencionales se ha demostrado que la istribución de tamaños de partículas del agua residual afluente puede afectar la eficiencia del tratamiento. Sin embargo, muy pocos estudios han sido llevados a cabo en HCFSS para determinar si los factores como la distribución de tamaño o características de la materia orgánica afectan la eficiencia del tratamiento. Por lo tanto, la hipótesis inicial de este trabajo está basada en la suposición de que en HCFSS, las características de la materia orgánica disuelta y particulada pueden afectar la eficiencia de eliminación de materia orgánica (DQO) y amonio. Los estudios realizados para probar esta hipótesis, fueron desarrollados utilizando pequeños contenedores experimentales poco profundos (0.27-0.3 m) con un área superficial de 0.54-0.77 m2. Estos sistemas fueron plantados con Phragmites australis y en la mayoría de los experimentos fueron alimentados de forma intermitente. El agua residual utilizada fue de dos tipos, sintética y agua residual urbana decantada. El agua residual sintética fue preparada con agua de grifo y compuesta de glucosa (materia orgánica fácilmente biodegradable), almidón (materia orgánica lentamente biodegradable) y nutrientes. En los capítulos 2 y 3 se hace una descripción sobre la eficiencia de los HCFSS experimentales. Estos sistemas tuvieron excelente eliminación de DQO con eficiencias entre 70 y 94% independiente del tipo de sustrato (glucosa o almidón) y de la carga orgánica superficial suministrada (5-6 g DQO/m2.d y 20-22 g DQO/m2.d). La eliminación de amonio en estos sistemas fue moderada, el sistema alimentado con glucosa tuvo mayor eficiencia (45-57%) con respecto al sistema alimentado con almidón (40-43%). La conductividad hidráulica fue menor en el sistema alimentado con glucosa, probablemente debido a un mayor crecimiento del biofilm.
En los HCFSS que operaron con agua residual urbana decantada, la aplicación de un pretratamiento físico-químico no mejoró la concentración de DQO en el efluente comparado con el sistema que no recibió tratamiento físico-químico (82 vs 88%), pero redujo la turbiedad y la concentración de DQO en el afluente. La eliminación de amonio fue alta y similar en ambos sistemas con un rango entre 63 y 94%. La conductividad hidráulica fue mayor (28 m/d) en el sistema con agua residual tratada que en el sistema que no recibió tratamiento (20 m/d). Los resultados de este estudio sugieren que un pretratameinto físico-químico podría evitar la acumulación de sólidos en la zona de entrada de los HCFSS.
El capítulo 5 describe un estudio diseñado para evaluar la eficiencia de eliminación en dos sistemas experimentales que operaron en forma intermitente y continua. Las tasas de eliminación de DQO fueron altas y similares en los dos sistemas con un valor promedio de 78%. La eliminación de amonio fue significativamente mas alta (P<0.05) en el sistema alimentado en intermitente comparado con el sistema alimentado en continuo (87 vs 69%).
El capítulo 6 proporciona información sobre la cantidad y calidad de sólidos acumulados en el medio granular de 6 humedales construidos a escala comercial. Los resultados de este estudio indicaron que la mayor cantidad de sólidos fue depositada en la zona de entrada (3-57 kg/m2) con diferencia significativa para la zona de salida (2-16 kg/m2). Esta alta cantidad de sólidos acumulada en la zona de entrada fue variable y estuvo relacionada con la carga orgánica y de sólidos recibida (3.1-17.5 g DQO/m2.d; 2.6-10 g SST/m2.d). El contenido de materia orgánica de los sólidos acumulados fue bajo (20%) y de difícil biodegradación tanto en condiciones aeróbicas como anaeróbicas. Los valores de conductividad hidráulica en estos sistemas fueron bajos (0-4 m/d) cerca de la zona de entrada con respecto a la zona de salida (12-200 m/d).
Por último, en el capítulo 7 se enumeran las principales conclusiones de cada uno de los aspectos estudiados y se mencionan algunas sugerencias para futuras investigaciones.
Subsurface-flow constructed wetlands (SSF CWs) constitute a proven technology for treatment of urban wastewater. One of the principal objectives of CW treatment is to remove organic matter, suspended solids and nutrients from the settled wastewater. The organic and mineral matter contained in urban wastewater is composed of a complexity of substances of different sizes and chemical compositions.
In conventional treatment systems it has been demonstrated that the particle size-frequency distribution of the influent wastewater can affect treatment efficiency. However, very few studies have been conducted in SSF CW to determine whether factors such as the size-frequency distribution or organic matter characteristics affect treatment efficiency. Thus the initial hypothesis of this work is based on the supposition that in SSF CW systems, the characteristics of the dissolved and particulate organic matter can influence the removal of COD and ammonium of wastewater. The designed studies were conducted in small experimental SSF CW units that were shallow (0.27 and 0.3 m), and with a surface area of 0.54-0.77 m2. The SSF CWs were planted with Phragmites australis and in most of the studies the treatments received wastewater on an intermittent basis. Wastewater used in these studies was either synthetic or settled urban wastewater. The synthetic wastewater was prepared with tap water and composed of glucose (organic matter easily biodegradable), starch (organic matter slowly biodegradable) and nutrients. In Chapters 2 and 3, details are provided to illustrate that shallow SSF CW provided excellent removal of COD, with average removal rates ranging from 70 to 94% irrespective of the type of organic ubstrate (glucose vs starch) or organic loading rates (5-6 g COD/m2.d to 20-22 g COD/m2.d). The ammonium-N removal in these systems was moderate, with the glucose-fed SSF CW providing marginally better removal (45 to 57%) as compared to the starch-fed system (40 to 43%). The hydraulic conductivity was low in the system fed with glucose due to the presence of a greater growth of biofilm.
In experimental SSF CW treating urban wastewater, the application of the physico-chemical pretreatment did not improve COD effluent concentrations as compared to the no-pretreatment control (82 vs 88%), but did reduce turbidity and COD concentration in the influent. The removal rates of ammonium-N were similar in both systems and ranged from 63 to 94%.
The hydraulic conductivity was higher (28 m/d) in the system with treated wastewater as compared to the control (20 m/d). These results indicate that the pretreatment could possibly help to reduce pervasive solids accummulation in the inlet zone (Chapter 4).
Chapter 5 describes a study designed to evaluate treatment efficiency in experimental SSF CW that were operated with either intermittent or continuous feeding. The COD removal rates were relatively high and merely identical in both systems, with an average value of 78%. Ammonium-N removal was significantly higher (P<0.05) in the intermittently fed system as compared to the continuously fed system (87 vs. 69%). The enhanced removal of COD and ammonium-N observed in the present studies were attributed to several factors including shallow wetland beds, macrophyte aboveground biomass, and more oxidizing conditions in the root zone.
Chapter 6 provides survey-type information for six full-scale SSF CW. The data indicated that the greatest amount of solids were deposited within the inlet zone (3-57 kg/m2), with significantly less solids near the outlet (2-16 kg/m2). It was apparent that the amount of solids deposited near the inlet was highly variable and was correlated with respective loading rates (3.1-17.5 g COD/m2.d; 2.6-10 g TSS/m2.d). Analyses of the accumulated solids showed them to be approximately 20% organic matter, extremely recalcitrant and difficult to degrade under either aerobic or anaerobic conditions. Hydraulic conductivity values were significantly lower near the inlet zone (0-4 m/d) as compared to the outlet zone (12-200 m/d).
Chapter 7 lists the main conclusions for each of the chapters and provides suggestions for future investigations.
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Hayzoun, Hanane. "Caractérisation et quantification de la charge polluante anthropique et industrielle dans le bassin du Sebou." Thesis, Toulon, 2014. http://www.theses.fr/2014TOUL0007/document.
Повний текст джерелаАнотація:
L’objectif principal de ce travail de thèse est d’évaluer l'impact des activités anthropiques sur le fonctionnement des systèmes aquatiques. L’impact des rejets urbains de Fès sur le Sebou, l'une des plus grandes rivières du Maroc, a été choisi pour cette étude. Les eaux usées domestiques et industrielles de la ville de Fès (~1M hab), véhiculées par son affluent l’oued Fès, sont rejetées dans le Sebou quasiment sans traitement. Deux sites du Sebou, en amont et en aval des rejets de la ville de Fès, et un site situé sur l’oued Fès ont été étudiés. Une campagne de prélèvement de carottes de sédiments et onze campagnes mensuelles de prélèvement d’eau et de matières en suspension (MES) ont été effectuées dans le but de quantifier les apports en nutriments, éléments traces métalliques (ETM) et carbone organique afin d’étudier la dynamique de ces polluants. Les résultats obtenus ont mis en évidence une augmentation des concentrations de presque tous les éléments étudiés en aval de la ville de Fès aussi bien dans la colonne d’eau que dans les sédiments. L’étude des carottes sédimentaires a révélé une contamination modérée par les butylétains totaux (ΣBT) avec la prédominance du monobutyétain dans les trois sites d’étude et sur toutes les profondeurs. Les sédiments du Sebou, en amont de la ville de Fès se caractérisent par les teneurs les plus faibles en métaux alors que ceux de l’oued Fès présentent une forte pollution polymétallique, accentuée dans les sédiments de surface, ce qui reflète clairement la signature d'apports anthropiques récents résultant des rejets non traités de la ville de Fès. L’augmentation consécutive des teneurs des métaux dans les sédiments du Sebou en aval de la confluence Fès-Sebou traduit l'influence significative des particules polluées de l’oued Fès. Dans la colonne d’eau, les concentrations mesurées dans le Sebou en amont de la confluence Fès-Sebou sont proches des rivières naturelles, à l’exception de Cl-, Cr, Na+ et NO3- dont les concentrations traduisent des pollutions agricoles et/ou domestiques. En revanche, la signature anthropique des rejets de la ville de Fès apparait évidente dans les eaux de l’oued Fès qui montrent des concentrations très élevées en ETM dissous et particulaires. La majorité des ETM provenant des apports anthropiques subissent des changements importants de leur coefficient de distribution Kd et présentent un comportement non conservatif dans le mélange entre les eaux du Sebou et celles de l’oued Fès. Ces résultats ont été confirmés par le modèle WHAM qui permet de prédire correctement le fractionnement dissous/particulaire, du Cu, Pb et Zn. La spéciation chimique de ces éléments ainsi que leur répartition dissous/particulaire apparaissent significativement influencées par les conditions particulières (anoxie, forte contamination, teneurs importantes en matière organique) des eaux de l’oued Fès. Ces conditions sont aussi à l’origine du comportement non conservatif de la majorité des éléments lors d'un mélange Sebou/Fès, observé aussi bien dans la colonne d’eau que dans les sédimentsThe main goal of this PhD was to evaluate the impact of the anthropogenic activities (urban, industrial or agricultural activities) on aquatic systems. The Fez metropolitan area and its impacts on the Sebou River, the main Moroccan river, were chosen as a case study. The Fez agglomeration (~1M hab), is surrounded by the Fez River, receiving the wastewaters of this developing city and then flowing into the Sebou. This work was performed on two sites along the Sebou River (upstream and downstream from the confluence with Fez River), and one site in the Fez River, downstream from the Fez city. One sampling campaigns of sediment cores and eleven sampling campaigns were performed during low flow conditions to quantify nutrients, organic carbon and trace metals and to study the dynamic and the transport of trace elements in the Sebou and Fez rivers. The obtained results revealed a global increase of studied elements in the Sebou River from upstream to downstream sampling site, in both sediments and water column. A moderate level of contamination by butyltins was observed, with monobutyltin being the dominant species across all sites and depths. The lowest level of metal pollution was identified in the Sebou's sediments upstream Fez city. Whilst the Fez' sediments were heavily polluted and exhibited bottom-up accumulation trends, which clearly evidence recent inputs from the untreated wastewaters of Fez city. The increase of metal levels in Sebou downstream sediments reflects a significant contribution of polluted particles from the Fez River. Dissolved and particulate concentrations of most of the analyzed elements in the Sebou, upstream from Fez city, are close to the natural rivers, except Cl-, Cr, Na+ et NO3- probably due to untreated urban inputs from several small/medium-size towns located upstream Fez. In the opposite On the contrary, high dissolved and particulate trace metals concentrations in the Fez River clearly indicated strong anthropogenic inputs from Fez city. Most of the studied trace metals originated from anthropogenic sources, underwent significant changes of Kd and behaved non-conservatively in the Sebou/Fez waters mixing due to drastic changes of the waters quality (anoxic condition, high concentration, high organic matter content). Dissolved/particulate partitioning were correctly assessed by WHAM-VII modeling for Cu, Pb and Zn, depicting significant differences in chemical speciation in Fez River when compared to Sebou one
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Persson, Ylva. "Chlorinated organic pollutants in soil and groundwater at chlorophenol-contaminated sawmill sites." Doctoral thesis, Umeå : Department of Chemistry, Umeå University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-989.
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