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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.
171

A stable isotope approach to trophic ecology : resolving food webs in intertidal ecosystems /

Hill, Jaclyn Marie. January 2007 (has links)
Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2008.
172

... The naiad fauna of the Huron river, in southeastern Michigan,

Van der Schalie, Henry, January 1938 (has links)
Thesis (Ph. D.)--University of Michigan, 1934. / Thesis note on label mounted on t.p.; also on p. [7]. Descriptive letterpress on versos facing the plates. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 78-83.
173

... The naiad fauna of the Huron river, in southeastern Michigan

Van der Schalie, Henry, January 1938 (has links)
Thesis (Ph. D.)--University of Michigan, 1934. / Thesis note on label mounted on t.p.; also on p. [7]. Descriptive letterpress on versos facing the plates. Bibliography: p. 78-83.
174

Influence of habitat complexity in structuring species-specific interactions and trophic linkages on oyster reefs of southeastern North Carolina /

Sonnier, Joseph M. January 2006 (has links) (PDF)
Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 53-59)
175

Απόβλητα ελαιοτριβείου και βιολογικές επιπτώσεις τους σε ιστούς του κοινού μυδιού Mytilus galloprovincialis

Δανελλάκης, Δημήτριος 10 June 2013 (has links)
Στην παρούσα μελέτη διερευνώνται οι πιθανές επιπτώσεις των αποβλήτων που προέρχονται από ελαιοτριβεία τριών φάσεων σε ιστούς του μυδιού Mytilus galloprovincialis. Άτομα που εκτέθηκαν για 5 ημέρες σε διαφορετικές αραιώσεις/συγκεντρώσεις του αποβλήτου παρουσίασαν μεγάλη θνησιμότητα σε αραιώσεις 1/1000 και 1/500, ενώ έκθεση των μυδιών σε μεγαλύτερες αραιώσεις του αποβλήτου (1/1000 και 1/10000), έδειξε μικρότερη θνησιμότητα. Οι υπο-θανατογόνες συγκεντρώσεις του αποβλήτου χρησιμοποιήθηκαν για την εκτίμηση α) της σταθερότητας των λυσοσωμικών μεμβρανών σε αιμοκύτταρα της αιμολέμφου (lysosomal membrane stability/LMS), β) της συχνότητας εμφάνισης μικροπυρήνων (micronuclei frequency/MN) και κυτταρικών ανωμαλιών σε αιμοκύτταρα, γ) της δραστικότητας της ακετυλ-χολινεστεράσης (AChE) στην αιμόλεμφο και τα βράγχια των εκτιθέμενων ατόμων, καθώς και ε) την εκτίμηση των επιπέδων των μεταλλοθειονινών (ΜΤ) στα βράγχια. Σύμφωνα με τα αποτελέσματα, άτομα που εκτέθηκαν σε αραιώσεις 1/1000 και 1/1000 του αποβλήτου, εμφάνισαν σημαντική μείωση του χρόνου αποσταθεροποίησης των λυσοσωμικών μεμβρανών των αιμοκυττάρων τους, με ταυτόχρονη αύξηση της συχνότητας εμφάνισης μικροπυρήνων και κυτταρικών ανωμαλιών. Επιπλέον, σημαντική μείωση της δραστικότητας της AChE παρατηρήθηκε σε όλους τους ιστούς (αιμόλεμφος και βράγχια), σε σχέση με τα αντίστοιχα επίπεδα δραστικότητας που μετρήθηκαν στους ιστούς ατόμων που δεν εκτέθηκαν στο απόβλητο, ενώ σημαντική αύξηση των επιπέδων ΜΤ παρατηρήθηκαν στα βράγχια των εκτιθέμενων ατόμων. Σύμφωνα με τα αποτελέσματα, το υψηλό οργανικό φορτίο, η μεγάλη συγκέντρωση φαινολών, καθώς και η ύπαρξη μεταλλικών στοιχείων μπορεί να ευθύνονται για την πρόκληση των επιβλαβών επιπτώσεων του αποβλήτου σε υδρόβιους οργανισμούς, όπως τα Δίθυρα μαλάκια, προκαλώντας σημαντικές βλάβες τόσο σε κυτταρικό όσο και σε μοριακό επίπεδο. / The present study investigates the biological effects of olive oil mill wastewaters (OMW) on tissues of mussels Mytilus galloprovincialis. Mussels exposed to different quantities of OMW (dilution factors 1/100 and 1/500) for 5 days showed increased levels of mortality, while mussels’ mortality observed after exposure to lower quantities of the OMW (dilution factors 1/1000 and 1/1000) was negligible. According to the latter, prepathological alterations occurred in tissues of mussels exposed to sub-lethal concentrations of OMW were further investigated with the use of stress-indices, such as lysosomal membrane stability (via the neutral red retention time assay/NRRT), acetylcholinesterase (AChE) activity, metallothionein (MT) content and micronuclei frequency (MN). According to the results of the present study, decreased NRR time values and significantly elevated levels of MN and nuclear abnormalities were observed in haemocytes of exposed mussels in each case. Moreover, mussels exposed to either 1/1000 or 1/10000 diluted OMW showed significantly decreased levels of AChE activity in haemolymph and gills, as well as increased MT levels in gills, compared with levels measured in the respective tissues of control mussels. The results of the present study indicates that biological effects of OMW could be due to the high organic loading toxicity of OMW, its high levels of phenolic compounds, as well as the presence of metallic anions, thus giving rise to the hypothesis that short-time exposure of marine organism to OMW could resulted in the induction of severe cytotoxic and genotoxic damage.
176

Avaliação regional da contaminação por hidrocarbonetos policíclicos aromáticos (HPAs) na região costeira do sudeste do Brasil usando mexilhões (Perna perna Linneaus 1758) como biomonitores / Avaliação regional da contaminação por hidrocarbonetos policíclicos aromáticos (HPAs) na região costeira do sudeste do Brasil usando mexilhões (Perna perna Linneaus 1758) como biomonitores / Regional assessment of PAHs contamination in SE Brazil using brown mussels (Perna perna, Linneaus 1758) / Regional assessment of PAHs contamination in SE Brazil using brown mussels (Perna perna, Linneaus 1758)

Renato Yoshimine Vieira 23 March 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do presente trabalho foi avaliar a presença e a distribuição de hidrocarbonetos policíclicos aromáticos (HPAs) em mexilhões coletados em 23 estações, divididas em três regiões: (i) cultivos localizados no Estado do Rio de Janeiro (7 estações) e em Ubatuba/SP (1 estação); (ii) áreas costeiras no Estado do Rio de Janeiro (7 estações) e (iii) na Baía de Guanabara/RJ (8 estações). Os HPAs foram determinados em triplicata de cada estação, sendo cada réplica formada por uma média de 10 indivíduos, através de cromatografia em fase gasosa acoplada a espectrometria de massas (GC/MS), totalizando 38 compostos entre parentais e alquilados. A concentração média do total de HPAs nos cultivos, excluindo o cultivo de Mombaça (Ilha Grande), foi de 24,7 22,3 ng g-1, para as áreas costeiras foi de 89,7 25,8 ng g-1 e para a Baía de Guanabara, 760,9 456,3 ng g-1. Esses resultados indicam que os cultivos (exceto Mombaça) e as áreas costeiras selecionadas apresentam baixos níveis de contaminação. Já na Baía de Guanabara, os resultados foram comparáveis a dados pretéritos e confirmam o estado de degradação ambiental da baía. Na amostra coletada no cultivo de Mombaça, a alta concentração do total de HPAs (584 ng g-1) e a predominância de compostos alquilados sobre parentais sugerem contaminação relativamente alta por hidrocarbonetos petrogênicos. A análise de agrupamento, considerando o total de HPAs, confirmou a separação entre as três áreas coletadas, mas com algumas exceções: (i) o cultivo de Mombaça assemelha-se ao grupo da Baía de Guanabara; (ii) a estação da Praia Vermelha, na saída da Baía de Guanabara, se assemelha com áreas costeiras fora da baía; (iii) as estações Ilha Redonda, Ilha Comprida e Pontal, distantes mais de 5 km da costa, se agruparam com os cultivos. Somente nas amostras da Baía de Guanabara foi possível avaliar a origem dos HPAs através da análise de componentes principais (PCA). A maioria das amostras da baía apresenta contaminação por fontes mistas de hidrocarbonetos, e apenas na praia Vermelha o aporte pirolítico é mais significativo. Por fim, ressalta-se que os níveis de HPAs nos mexilhões das três áreas ficaram abaixo de valores de referência exigidos internacionalmente para o consumo humano. No entanto, é necessário uma análise de risco específica para melhor compreender a qualidade do mexilhão para consumo humano, particularmente os da Baía de Guanabara. / The aim of the present study was to evaluate the presence and distribution of polycyclic aromatic hydrocarbons (PAHs) in mussels collected from 23 stations, divided into three regions: (i) mussel crops in the State of Rio de Janeiro (7 sampling stations) and Ubatuba/SP (1 sampling station), (ii) coastal areas of the State of Rio de Janeiro (7 sampling stations) and (iii) Guanabara Bay/RJ (8 sampling stations). The PAHs were determined in triplicate for each station, with each replica composed of an average of 10 individuals, by gas chromatography coupled to mass spectrometry (GC/MS), totaling 38 compounds between parental and alkylated PAH. The mean total PAH concentration in the crops, with the exception of Mombaça (at Ilha Grande), was of 24.7 22.3 ng g-1, while the mean for the coastal areas was of 89.7 25.8 ng g-1, and of 760.9 456.3 ng g-1 for the Guanabara Bay. These results indicate that the mussel crops (with the exception of Mombaça) and the selected coastal areas present low contamination levels. Guanabara Bay, on the other hand, showed results comparable to past data, confirming the state of environmental degradation of the bay. In samples collected at the Mombaça mussel crop, the high concentration of total PAHs (584 ng g-1) and the predominance of alkylated compounds over parent compounds suggest the presence of relatively high contamination by petrogenic hydrocarbons. The cluster analysis, considering total PAHs, confirmed the separation between the three sampled areas, although some exceptions were noted: (i) the Mombaça crop resembles the Guanabara Bay group, (ii) the Praia Vermelha station, at the Guanabara Bay exit, resembles coastal areas outside the bay, (iii) the Ilha Redonda, Ilha Comprida and Pontal stations, over 5 km distant from the coast, were grouped with the other mussel crops. Only in samples from the Guanabara Bay was it possible to evaluate PAH origin by use of the principal component analysis (PCA). Most samples of the bay show mixed hydrocarbon contamination sources, and pyrolytic contribution was more significant only at the Praia Vermelha station. Finally, we emphasize that the PAH levels in mussels from the three areas were below the international reference values for human consumption. However, a specific risk analysis is necessary in order to better understand the quality of mussels for human consumption, particularly those from the Guanabara Bay.
177

Bioacumulacao e eliminacao de mercurio (sup(203)Hg) no mexilhao (Perna perna, Linne, 1758) .Modelo cinetico para avaliar o risco de ingestao no homem

MALAGRINO, WALDIR 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:48:15Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:55Z (GMT). No. of bitstreams: 1 09455.pdf: 4871108 bytes, checksum: cdb33a154f97f7b1de400d0a95b20a24 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
178

A stable isotope approach to trophic ecology resolving food webs in intertidal ecosystems

Hill, Jaclyn Marie January 2008 (has links)
There are broad differences in regional oceanography and primary production around the South African coast, which we might expect to give rise to major differences in trophic pathways. δ⁻¹³C and δ⁻¹⁵N isotopic ratios of suspended particulate matter (SPM), mussels, various intertidal consumers and common macroalgae along the South African coastline were explored using stable isotope analysis to investigate biogeographic and temporal variability of isotopic signatures of marine intertidal consumers and their food sources around the coast of South Africa, with a focus on evaluating the dependence of intertidal mussels on phytoplankton and macroalgal-derived organic carbon. Isotopic equilibration rates of four mussel tissues were determined through laboratory feeding experiments, which established that adductor tissue had the slowest isotopic turnover rate, and was subsequently used as an indication of overall mussel diet. Biogeographic, temporal and nearshore/offshore trends of isotopic ratios of SPM were investigated along 10km transects perpendicular to the coast and SPM exhibited overall trends of carbon depletion when moving from west to east along the coastline and from nearshore to offshore water, in both cases suggesting a shift from macrophyte detritus to a phytoplankton signature. δ⁻¹³C signatures of SPM also revealed temporal and biogeographic variation that had strong ties to local oceanography, being closely correlated to regional hydrographic features and tidal influences. Mixing models indicated filter feeders demonstrated over 50% dependence on nearshore SPM for organic carbon and it was possible to categorize them into geographic groups based on their carbon and nitrogen signatures, suggesting biogeographic shifts in resources. Biogeographic shifts in diet were also seen in some grazers. Difficulties in relating macroalgae to mussel diet led to investigations into the isotopic changes associated with macroalgal decomposition. Variation in photosynthetic fractionation, leaching and microbial mineralization are believed to have resulted from species-specific patterns of degradation. Although the strong links between carbon signatures and local oceanography indicate that stable isotope analysis is a powerful tool for the study of water mixing and coastal hydrography in relation to food-web analyses, substantial variation in fractionation of primary consumers, along with different periods of time integration between consumers and their food sources must be considered in future studies, to resolve trophic links in marine food webs successfully.
179

Morfologie lastur perlorodky říční (Margaritifera margaritifera) / Shells morphology of pearl mussel (\kur{Margaritifera margaritifera})

PŮBALOVÁ, Lenka January 2017 (has links)
The aim of this study was to determine the differences of freshwater pearl mussels (Margaritifera margaritifera) originated from two geographically isolated areas according to morphological parameters and the age of dead freshwater pearl mussel Data were collected from four localities, i. e. from the two areas (Šumava: Blanice, Zlatý potok and Aš area: Bystřina and Rokytnice). The average length of shells was 95.8 mm, thickness 27.9 mm, height 43.4 mm. The ligament was eroded from 57 % and index (ration between thickness and length x 50) was on average 32 %. Thickness of the shells and the percentage of eroded ligament differed between the two areas. Both of these parameters were higher in Aš area. Other morphological parameters (length and height of the shells and the above mentioned index) were similar in both areas. Assessment of age according to the growth lines in the ligament was significantly higher than the evaluation using growth lines on the surface of the shells. Mean age of freshwater pearl mussels determined using growth lines in the ligament was 36 years old and on the surface of the shells was 30 years old. Age according to the growth lines in the ligament better correlated with the length of the shell than percentage of eroded ligament. Age of dead freshwater pearl mussel was comparable in both areas, however differed between localities. Rokytnice proved to be the most suitable habitat for freshwater pearl mussels according to the age estimation.
180

Avaliação regional da contaminação por hidrocarbonetos policíclicos aromáticos (HPAs) na região costeira do sudeste do Brasil usando mexilhões (Perna perna Linneaus 1758) como biomonitores / Avaliação regional da contaminação por hidrocarbonetos policíclicos aromáticos (HPAs) na região costeira do sudeste do Brasil usando mexilhões (Perna perna Linneaus 1758) como biomonitores / Regional assessment of PAHs contamination in SE Brazil using brown mussels (Perna perna, Linneaus 1758) / Regional assessment of PAHs contamination in SE Brazil using brown mussels (Perna perna, Linneaus 1758)

Renato Yoshimine Vieira 23 March 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do presente trabalho foi avaliar a presença e a distribuição de hidrocarbonetos policíclicos aromáticos (HPAs) em mexilhões coletados em 23 estações, divididas em três regiões: (i) cultivos localizados no Estado do Rio de Janeiro (7 estações) e em Ubatuba/SP (1 estação); (ii) áreas costeiras no Estado do Rio de Janeiro (7 estações) e (iii) na Baía de Guanabara/RJ (8 estações). Os HPAs foram determinados em triplicata de cada estação, sendo cada réplica formada por uma média de 10 indivíduos, através de cromatografia em fase gasosa acoplada a espectrometria de massas (GC/MS), totalizando 38 compostos entre parentais e alquilados. A concentração média do total de HPAs nos cultivos, excluindo o cultivo de Mombaça (Ilha Grande), foi de 24,7 22,3 ng g-1, para as áreas costeiras foi de 89,7 25,8 ng g-1 e para a Baía de Guanabara, 760,9 456,3 ng g-1. Esses resultados indicam que os cultivos (exceto Mombaça) e as áreas costeiras selecionadas apresentam baixos níveis de contaminação. Já na Baía de Guanabara, os resultados foram comparáveis a dados pretéritos e confirmam o estado de degradação ambiental da baía. Na amostra coletada no cultivo de Mombaça, a alta concentração do total de HPAs (584 ng g-1) e a predominância de compostos alquilados sobre parentais sugerem contaminação relativamente alta por hidrocarbonetos petrogênicos. A análise de agrupamento, considerando o total de HPAs, confirmou a separação entre as três áreas coletadas, mas com algumas exceções: (i) o cultivo de Mombaça assemelha-se ao grupo da Baía de Guanabara; (ii) a estação da Praia Vermelha, na saída da Baía de Guanabara, se assemelha com áreas costeiras fora da baía; (iii) as estações Ilha Redonda, Ilha Comprida e Pontal, distantes mais de 5 km da costa, se agruparam com os cultivos. Somente nas amostras da Baía de Guanabara foi possível avaliar a origem dos HPAs através da análise de componentes principais (PCA). A maioria das amostras da baía apresenta contaminação por fontes mistas de hidrocarbonetos, e apenas na praia Vermelha o aporte pirolítico é mais significativo. Por fim, ressalta-se que os níveis de HPAs nos mexilhões das três áreas ficaram abaixo de valores de referência exigidos internacionalmente para o consumo humano. No entanto, é necessário uma análise de risco específica para melhor compreender a qualidade do mexilhão para consumo humano, particularmente os da Baía de Guanabara. / The aim of the present study was to evaluate the presence and distribution of polycyclic aromatic hydrocarbons (PAHs) in mussels collected from 23 stations, divided into three regions: (i) mussel crops in the State of Rio de Janeiro (7 sampling stations) and Ubatuba/SP (1 sampling station), (ii) coastal areas of the State of Rio de Janeiro (7 sampling stations) and (iii) Guanabara Bay/RJ (8 sampling stations). The PAHs were determined in triplicate for each station, with each replica composed of an average of 10 individuals, by gas chromatography coupled to mass spectrometry (GC/MS), totaling 38 compounds between parental and alkylated PAH. The mean total PAH concentration in the crops, with the exception of Mombaça (at Ilha Grande), was of 24.7 22.3 ng g-1, while the mean for the coastal areas was of 89.7 25.8 ng g-1, and of 760.9 456.3 ng g-1 for the Guanabara Bay. These results indicate that the mussel crops (with the exception of Mombaça) and the selected coastal areas present low contamination levels. Guanabara Bay, on the other hand, showed results comparable to past data, confirming the state of environmental degradation of the bay. In samples collected at the Mombaça mussel crop, the high concentration of total PAHs (584 ng g-1) and the predominance of alkylated compounds over parent compounds suggest the presence of relatively high contamination by petrogenic hydrocarbons. The cluster analysis, considering total PAHs, confirmed the separation between the three sampled areas, although some exceptions were noted: (i) the Mombaça crop resembles the Guanabara Bay group, (ii) the Praia Vermelha station, at the Guanabara Bay exit, resembles coastal areas outside the bay, (iii) the Ilha Redonda, Ilha Comprida and Pontal stations, over 5 km distant from the coast, were grouped with the other mussel crops. Only in samples from the Guanabara Bay was it possible to evaluate PAH origin by use of the principal component analysis (PCA). Most samples of the bay show mixed hydrocarbon contamination sources, and pyrolytic contribution was more significant only at the Praia Vermelha station. Finally, we emphasize that the PAH levels in mussels from the three areas were below the international reference values for human consumption. However, a specific risk analysis is necessary in order to better understand the quality of mussels for human consumption, particularly those from the Guanabara Bay.

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