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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Methane fluxes from the Baltic Sea : A first look at measured fluxes of shallow near-coastal waters using floating chambers

Svensson, Johan, Westerholm, Viktor January 2010 (has links)
Methane is an important green house gas as it is responsible for 15-20 % of the green house effect. Marine environments in general and shallow near-coastal waters specifically may be important contributors of methane emissions but are as of today poorly studied.  In this study we measured total fluxes of methane from shallow near-coastal waters at two sites along the east coast of Sweden. The sea-to-air emissions of methane where captured using floating chambers. This gave measured fluxes as compared to earlier studies of the Baltic Sea where calculated fluxes are often used. Measured fluxes have the merit of not having to rely on several highly varying and complex variables e.g. mean wind speed and piston velocity that vary and give an uncertainty to the results.  The fluxes ranged from -2.14 to 0.37 mg CH4 m-2 d-1 with a mean of 0.05 mg CH4 m-2 d-1. The results show a correlation, however not strong, between depth and methane. No difference in flux between the study sites could be seen. We look forward to further studies using floating chambers on shallow near-coastal waters with longer sampling periods to catch seasonal variations.
32

Marine aquatic environment as a source of potential human pathogens : studies on prevalence, ecology and characterisation of Aeromonas spp. and Vibrio vulnificus isolated from marine environment /

Dumontet, Stefano. January 2002 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2002. / Härtill 4 uppsatser.
33

Avaliação dos teores de Br, Cl, K, Mg, Mn e V em mexilhões Perna perna (Linnaeus, 1758: Mollusca, Bivalvia) coletados no litoral do estado de São Paulo, Brasil / Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca, bivalvia) collected in coast of São Paulo, Brazil

SEO, DANIELE 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:05Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
34

Avaliação dos teores de Br, Cl, K, Mg, Mn e V em mexilhões Perna perna (Linnaeus, 1758: Mollusca, Bivalvia) coletados no litoral do estado de São Paulo, Brasil / Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca, bivalvia) collected in coast of São Paulo, Brazil

SEO, DANIELE 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:02Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:05Z (GMT). No. of bitstreams: 0 / O ambiente costeiro tem sido fortemente alterado em função de múltiplos impactos ambientais decorrentes das atividades antrópicas, como por exemplo, o escoamento de esgoto proveniente de áreas urbanas, a liberação de inúmeros produtos químicos das indústrias, a agricultura e o fluxo de embarcações, que podem acarretar vazamentos acidentais de petróleo e derivados, combustíveis e outros produtos transportados por via marítima. Neste contexto, um dos meios para avaliação da contaminação ambiental causada por essas substâncias potencialmente tóxicas em água do mar é a monitoração por meio de diferentes espécies de bivalves, que tem sido utilizada por diversos pesquisadores, do Brasil e do exterior. No que se refere aos moluscos bivalves, particularmente os mexilhões, o seu uso no biomonitoramento da contaminação marinha deve-se principalmente à sua ampla distribuição geográfica, hábito séssil e habilidade de concentrar metais tóxicos em até 102 - 105 vezes em relação às concentrações detectadas na água. No presente trabalho, foi empregado o biomonitoramento passivo com o uso do molusco bivalve Perna perna com relação aos elementos Br, Cl, K, Mg, Mn e V. Foram escolhidos estes elementos uma vez que eles podem ser determinados pelo método de INAA (Análise por Ativação com Nêutrons Instrumental), por meio da irradiação curta o que proporciona análises mais rápidas e também por serem importantes do ponto de vista nutricional ou ambiental. O objetivo do presente trabalho foi avaliar os teores de Br, Cl, K, Mg, Mn e V em amostras de mexilhões Perna perna (Linnaeus, 1758: Mollusca, Bivalvia) coletados em regiões costeiras de São Paulo sujeitas à contaminação antrópica (Ponta de Itaipu e Ilha das Palmas, em Santos), comparando os valores obtidos nos sítios possivelmente impactados com os valores do sítio controle situado na Praia da Cocanha, em Caraguatatuba. Os pontos de coleta no litoral de São Paulo estão localizados nas regiões geográficas 23º 37 S 45º 24 W (Caraguatatuba) e 23º 57\' S - 46º 20\' W (Santos). A coleta dos organismos foi realizada em todas as estações do ano, com início na primavera de 2008 e término no inverno de 2009. As amostras coletadas foram limpas, trituradas, homogeneizadas e secas por meio da liofilização para posterior INAA. O procedimento de INAA consistiu em irradiar alíquotas das amostras obtidas na forma de pó em invólucros de polietileno no reator nuclear IEA R1 do IPEN/CNEN - SP juntamente com padrões sintéticos de elementos. O tempo de irradiação no reator foi de 8 a 10 s e sob o fluxo de nêutrons térmicos de 6,6 x 1012 n cm-2 s-1. As concentrações dos elementos foram calculadas pelo método comparativo. O procedimento de INAA foi validado com relação à exatidão e precisão, por meio das análises dos materiais de referência certificados NIST SRM 1566b Oyster Tissue e NIST SRM 2876 Mussel Tissue. Os resultados destes materiais de referência certificados indicaram uma boa qualidade dos resultados com relação à precisão e exatidão. As faixas das concentrações (em base seca) dos elementos obtidos nos mexilhões coletados em Santos e na Praia da Cocanha para as quatro estações do ano foram de: 173,80 a 358,99 mg kg-1 para Br; 45658 ± 1811 a 109166 ± 824 mg kg-1 para Cl; 7043 ± 856 a 12506 ± 675 mg kg-1 para K; 2774 ± 211 a 5691 ± 717 mg kg-1 para Mg; 7,01 ± 0,30 a 29,74 ± 3,32 mg kg-1 para Mn e 0,77 ± 0,02 a 3,43 ± 0,28 mg kg-1 para V. Foi estudada a variação sazonal e espacial das concentrações desses elementos e também foram comparados esses resultados com valores da literatura. A partir dos resultados obtidos pode - se concluir que os mexilhões da espécie Perna perna, podem ser utilizados como biomonitores da contaminação marinha. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
35

TRACKING WASTEWATER EMISSIONS IN RIVERS ENTERING GULF OF BOTHNIA COAST

Mkandawire, Helen January 2023 (has links)
The Gulf of Bothnia consists of two sub-basins in the northern Baltic Sea: the Bothnian Sea (salinity 4-5‰) and Bothnian Bay (salinity 2-3‰). Changing nutrient concentrations and signs of eutrophication has recently been observed in the Gulf of Bothnia. Many rivers enter this sea area, and potentially river inflows constitute a source of nutrient pollution via waste-water emissions. The aim of this study was to elucidate effects of waste-water emissions in four rivers in northern Sweden, Luleå, Skellefteå, Umeå and Söderhamn. My approach was to compare nutrient concentrations at upstream and downstream sampling stations related to the position of waste-water treatment plants. Temporal data from 2006 to 2021 were used and statistically analyzed using non-parametric tests to establish spatial and temporal patterns for nutrient discharged to the coast. The results showed that there are statistically differences in dissolved inorganic phosphorus (DIP) in the form of phosphate (PO4), ammonia (NH4) and total nitrogen (TotN) between the upstream and downstream of Luleå and Umeå wastewater treatment plants. No statistically significant differences were observed in the upstream and downstream data for Söderhamn and Skellefteå. This suggest that better management and mitigation of nutrient loading from wastewater treatment plants that serve higher populations is paramount to achieve the zero-eutrophication goal in the Gulf of Bothnia.
36

ANALYSIS OF MONITORING NETWORK SPATIAL AND TEMPORAL REDUCTION AND THEIR CONSEQUENCES ON THE ECOLOGICAL CLASSIFICATION IN THE SCOPE OF WATER FRAME DIRECTIVE

Abramic, Andrej 15 May 2013 (has links)
La Directiva Marco Europea del Agua es la norma legislativa más importante que ha establecido la Comisión Europea, en materia de aguas, y constituye un importante avance para lograr una gestión sostenible del agua. Esta norma exige que todas las aguas, alcancen en el 2015 un status bueno e indica los pasos a seguir para conseguirlo, mediante el establecimiento de objetivos ecológicos y medioambientales en las mismas. Para concretar estos objetivos, la DMA ha establecido un sistema de indicadores biológicos, hidro-morfológicos y fisicoquímicos que determinan la calidad ecológica de las diferentes masas de agua. Para proporcionar una clasificación ecológica de las masas de agua costeras en la Comunidad Valencia existe una red de monitoreo costera que analiza la biomasa de fitoplancton, de forma indirecta a partir de la clorofila a. En las mismas, se establece la calidad de las aguas costeras en base al valor del percentil 90 del total de mediciones de clorofila a recogidas en sucesivas campañas mensuales durante un período de 5 años. Se ha considerado la posibilidad de reducir el número de campañas realizadas a lo largo del año y la posibilidad de reducir el número de estaciones revisadas en cada campaña y que consecuencias lleva esta reducción por estado ecológico. Los resultados del estudio exploratorio para la reducción temporal, muestran que una reducción no controlada en el número de campañas realizadas a lo largo del año en las aguas costeras valencianas, puede producir alteraciones impredecibles en su clasificación ecológica. Un estudio conjunto de las series pluviométricas, de oleaje, salinidad y clorofila a, para los tres climas marítimos presentes en las aguas costeras valencianas, ha permitido observar que el equilibrio trófico de los ecosistemas, en esta zona, depende tanto de la influencia antropogénica como de factores medioambientales determinados por la estacionalidad e irregularidad del clima. En base a ello, se han definido tres tipos de ecosistema / Abramic, A. (2011). ANALYSIS OF MONITORING NETWORK SPATIAL AND TEMPORAL REDUCTION AND THEIR CONSEQUENCES ON THE ECOLOGICAL CLASSIFICATION IN THE SCOPE OF WATER FRAME DIRECTIVE [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/28851
37

Qualité des eaux côtières du Sud du Golfe de Gascogne par télédétection spatiale : méthodologie de détermination et de quantification de substances particulaires et dissoutes

Petus, Caroline 18 December 2009 (has links)
Les eaux côtières du Sud du Golfe de Gascogne sont soumises à l’expulsion d’un panache fluvial au niveau de l’estuaire de l’Adour. Ces eaux douces peuvent entrainer de fortes variations des concentrations en matières minérales en suspension (MSM, en mg,l-1), en chlorophylle- a (Chla, en mg,m-3) et en matière organiques dissoutes colorées (MODC, en mg,l-1) contenues dans les eaux côtières. En modifiant la transparence de l’eau et en charriant des nutriments et des bactéries, elles peuvent affecter la productivité biologique et avoir un impact significatif sur la santé humaine. Notre étude a pour but de développer des algorithmes empiriques et de tester l’efficacité des images MODIS-Aqua pour la cartographie des substances particulaires et dissoutes contenues dans les eaux côtières soumises à l'influence du panache de l'Adour. Dans cet objectif, deux missions océanographiques ont été réalisées afin de mesurer simultanément les MSM, la turbidité (en NTU), la Chla et les MODC et la réflectance de télédétection de l’eau in-situ. Deux algorithmes empiriques opérationnels pour la quantification des matières minérales en suspension et de la turbidité ont été développés. Une automatisation du traitement des images MODIS-Aqua déjà corrigées des effets atmosphériques et à la résolution de 250 mètres (produit MYD09GQ) a été réalisée. Ce système opérationnel a permis de cartographier les concentrations en sédiments en suspension contenus dans le panache sur 246 jours, entre 2006 et 2009. La première étude à grande échelle spatiale et temporelle de la dynamique hydro-sédimentaire du panache de l'Adour a ainsi pu être réalisée. Finalement, plusieurs algorithmes ont été proposés pour la quantification des concentrations en chlorophylle-a dans le sud du Golfe de Gascogne. Ces relations empiriques devront être testées sur de nouvelles mesures in-situ afin de préciser leurs limites de validité. Notre étude montre l’apport de l’imagerie satellitaire MODIS pour la surveillance du panache de l'Adour. A plus long terme, un système efficace de surveillance de la qualité des eaux côtières de la côte Aquitaine pourrait être envisagé. / The southern Bay of Biscay coastal waters are under the direct influence of the freshwater plume from the Adour estuary. The river outflow leads to a strong variability in the concentration of mineral suspended matters (MSM in mg l-1), chlorophyll-a (Chla, mg, m-3) and colored dissolved organic matters (CDOM in mg l-1) contained in coastal waters. By changing the transparency of the water and carrying nutrients and bacteria, they may affect biological productivity and have a significant impact on human health. Our study aims to develop empirical algorithms and test the efficiency of MODIS-Aqua imagery to map particulate and dissolved substances contained in coastal waters under the influence of the Adour plume. In this aim, two oceanographic missions were carried out to measure simultaneously the MSM, turbidity, Chla and CDOM and the remote sensing reflectance of water. Two empirical operational algorithms for quantification of suspended mineral matters and turbidity have been developed. An automated processing of atmospherically-corrected MODIS-Aqua-250m product (MYD09GQ product) was performed. This operating system has been used to map the concentrations of suspended sediment content in the plume at 246 days between 2006 and 2009. Thus, the first study at large spatial and temporal scale of the Adour plume dynamics has been achieved. Finally, several algorithms have been proposed in order to quantify the concentrations of chlorophyll-a in the southern Bay of Biscay. These empirical relations must be tested on new in-situ measurements to clarify their validity limits. Our study shows the contribution of the MODIS satellite imagery to monitor the Adour plume. In future, an effective monitoring system of Aquitaine coastal water quality could be considered.
38

Pasyviųjų priemaišų pernašos ypatumai Baltijos jūros Lietuvos priekrantėje / Passive admixture transfer peculiarity at the Lithuanian coast of the Baltic Sea

Daunaravičienė, Asta 21 January 2008 (has links)
Pasyviųjų priemaišų jūrinėje aplinkoje įvertinimas ypač svarbus gamtosauginiu aspektu. Ypatingas dėmesys skiriamas Baltijos jūros ekologinei būklei, kurią lemia jūros dubens ypatybės, silpnas ryšys su Pasauliniu vandenynu, klimatinės ir hidrometeorologinės sąlygos. Pastaraisiais dešimtmečiais jūros baseine didėja antropogeninės kilmės teršalų kiekis. Branduolinės fizikos ir technikos plėtra neišvengiamai sukelia technogeninės kilmės radionuklidų patekimą į jūrinę aplinką. Daug dėmesio skiriama 137Cs radionuklidui, nes iki šiol jūros vandens tyrimai rodo aukštas šio radionuklido tūrinio aktyvumo reikšmes. Be to, 137Cs radionuklidas geras indikatorius, tiriant kitų pasyviųjų priemaišų migraciją Baltijos jūros vandenyje. Daug mokslininkų nagrinėja problemas, susijusias su technogeninės kilmės radionuklidų kiekiais, jų sklaida ir poveikiu jūrinei aplinkai. Tačiau darbų, kuriuose būtų nagrinėjama radionuklidų tūrinių aktyvumų pokyčių bei pernašos Baltijos jūros priekrantės vandenyje problema, praktiškai nėra. Atsižvelgiant į tai, šiame darbe nustatytas 137Cs radionuklido tūrinis aktyvumas Baltijos jūros Lietuvos priekrantės paviršiniame vandenyje bei įvertinti hidrometeorologiniai parametrai. 137Cs radionuklido tūrinis aktyvumas Baltijos jūros vandenyje nėra pastovus, todėl aktualu parinkti tinkamus nustatymo metodus ir vertinti jo pokyčių tendencijas. Įvertinus radiocezio tūrinio aktyvumo pokyčius priekrantės vandenyje, galima modeliuoti ir prognozuoti taršos šaltinio atsiradimo... [toliau žr. visą tekstą] / The evaluation of the passive admixture transfer in the marine environment is very significant from the point of view of environmental protection. A particular attention is devoted to the Baltic Sea ecological state, which is strongly influenced by the peculiarities of the sea bottom, weak connection with the World Ocean, climatic and hydrometeorological conditions. During the recent decades, the tendency of increment of the amount of anthropogenic pollutants is observed. The development of nuclear energetics and technology inevitably causes the spread of radionuclides of technical origin in the marine environment. The major attention is paid to the investigation of the radionuclide 137Cs distribution, since the investigations show the high values of the volumetric activity of this radionuclide to be present in the sea water thus far. Besides that, 137Cs radionuclide can be used as a tracer in investigations of the migration of other passive admixtures in the Baltic Sea water. Quite a number of scientists research the problems related with the amounts of the radionuclide of technical origin, their spread and impact on the marine environment. However, the works considering a problem of the variations of volumetric activity of radionuclides and their transfer in the coastal waters of the Baltic Sea practically are not encountered. Considering that, the volumetric activity of radionuclide 137Cs in the coastal surface waters of the Lithuanian territorial zone of the Baltic Sea... [to full text]
39

Passive admixture transfer peculiarity at the Lithuanian coast of the Baltic Sea / Pasyviųjų priemaišų pernašos ypatumai Baltijos jūros Lietuvos priekrantėje

Daunaravičienė, Asta 21 January 2008 (has links)
The evaluation of the passive admixture transfer in the marine environment is very significant from the point of view of environmental protection. A particular attention is devoted to the Baltic Sea ecological state, which is strongly influenced by the peculiarities of the sea bottom, weak connection with the World Ocean, climatic and hydrometeorological conditions. During the recent decades, the tendency of increment of the amount of anthropogenic pollutants is observed. The development of nuclear energetics and technology inevitably causes the spread of radionuclides of technical origin in the marine environment. The major attention is paid to the investigation of the radionuclide 137Cs distribution, since the investigations show the high values of the volumetric activity of this radionuclide to be present in the sea water thus far. Besides that, 137Cs radionuclide can be used as a tracer in investigations of the migration of other passive admixtures in the Baltic Sea water. Quite a number of scientists research the problems related with the amounts of the radionuclide of technical origin, their spread and impact on the marine environment. However, the works considering a problem of the variations of volumetric activity of radionuclides and their transfer in the coastal waters of the Baltic Sea practically are not encountered. Considering that, the volumetric activity of radionuclide 137Cs in the coastal surface waters of the Lithuanian territorial zone of the Baltic Sea... [to full text] / Pasyviųjų priemaišų jūrinėje aplinkoje įvertinimas ypač svarbus gamtosauginiu aspektu. Ypatingas dėmesys skiriamas Baltijos jūros ekologinei būklei, kurią lemia jūros dubens ypatybės, silpnas ryšys su Pasauliniu vandenynu, klimatinės ir hidrometeorologinės sąlygos. Pastaraisiais dešimtmečiais jūros baseine didėja antropogeninės kilmės teršalų kiekis. Branduolinės fizikos ir technikos plėtra neišvengiamai sukelia technogeninės kilmės radionuklidų patekimą į jūrinę aplinką. Daug dėmesio skiriama 137Cs radionuklidui, nes iki šiol jūros vandens tyrimai rodo aukštas šio radionuklido tūrinio aktyvumo reikšmes. Be to, 137Cs radionuklidas geras indikatorius, tiriant kitų pasyviųjų priemaišų migraciją Baltijos jūros vandenyje. Daug mokslininkų nagrinėja problemas, susijusias su technogeninės kilmės radionuklidų kiekiais, jų sklaida ir poveikiu jūrinei aplinkai. Tačiau darbų, kuriuose būtų nagrinėjama radionuklidų tūrinių aktyvumų pokyčių bei pernašos Baltijos jūros priekrantės vandenyje problema, praktiškai nėra. Atsižvelgiant į tai, šiame darbe nustatytas 137Cs radionuklido tūrinis aktyvumas Baltijos jūros Lietuvos priekrantės paviršiniame vandenyje bei įvertinti hidrometeorologiniai parametrai. 137Cs radionuklido tūrinis aktyvumas Baltijos jūros vandenyje nėra pastovus, todėl aktualu parinkti tinkamus nustatymo metodus ir vertinti jo pokyčių tendencijas. Įvertinus radiocezio tūrinio aktyvumo pokyčius priekrantės vandenyje, galima modeliuoti ir prognozuoti taršos šaltinio atsiradimo... [toliau žr. visą tekstą]
40

Topics on the ecological economics of coastal zones : linking land uses, marine eutrophication, and fisheries /

Paulsen, Sandra Silva, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

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