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Thesis (M.S.) in Marine Biology--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 56-65).

Thesis (Ph.D.)--Memorial University of Newfoundland, 1999. / Bibliography: leaves 142-170.

In this study the effects of the vegetable oils rapeseed, linseed, olive and sunflower oil on mussel performance were investigated. In view of the scarse knowledge of the effects of vegetable oil spills on marine life, unlike petroleum spills which have been extensively studied, this investigation was directed towards an evaluation of the impact of vegetable oil contamination in the marine environment using Mytilus edulis as a bioindicator organism. The growth of mussels, their tolerance to changing salinities and temperatures, their behaviour and vegetable oil metabolism were studied. Fatty acid composition of mussels. microalgae and vegetable oils was also determined. All the vegetable oils studied had an inhibitory effect on the growth of Mytilus edulis, the growth rate of mussels after four weeks of exposure to the oils being 5 times lower than the growth rates of the control mussels. Growth rates were assessed by a photographic method which proved to be practical and provided sufficient precision in detect small increases in growth. Vegetable oils caused mortalities and they changed the fatty acid composition of mussels. Other biological responses of mussels are also affected by sunflower oil exposure: gaping time, tolerance to low salinities and foot extension activity, of which the latter may be of ecological significance. An uptake and accumulation of fatty acids in mussels marked the presence of vegetable oils, however, fatty acid metabolism was only detected after the oils had been removed. The results of this study indicate that contrary to what is believed, vegetable oils should not be overlooked under the argument of their edibility and biodegradability but instead should be included in oil spill contingency planning because they can cause mortality and disrupt the growth of wild and cultured mussels.

La présente thèse comprend deux grandes sections, la première traitant des macro-crustacés, la crevette de vase Austinogebia edulis et la seconde des micro-crustacés, le copépode Eurytemora affinis. Les objectifs étaient de 1. Explorer le rôle d’A. edulis en tant qu’ingénieur écologique, 2. Effets du Cd sur les enzymes oxydatives et la morphologie d’A. edulis, 3. Évaluer la variation spatiale et temporelle des polluants organiques persistants (POP) dans l’habitat naturel d’A. edulis, 4. Explorer l’effet d’un cocktail de 4 métaux lourds sur E. affinis et décrire l’effet des sédiments en suspension sur E. affinis en suivant une approche multigénérationnelle. Pour le premier objectif, nous soulignons les différences significatives entre les murs des terriers et les lumens. La paroi du terrier d’A. edulis présentait une faible perméabilité et augmentait la résistance. Statistiquement, on a remarqué une différence importante dans la comparaison entre la composition des sédiments de la paroi du terrier et le fond. La paroi du terrier se composait d’une teneur en matière organique 24 fois supérieure à celle d’un individu de crevette. Ainsi, ils transforment les caractéristiques des sédiments en tant qu’ingénieur écologique, ce qui devrait avoir un impact écologique important sur l’écosystème. De plus, lors de l’exposition au Cd, les activités des enzymes antioxydantes (SOD, CAT et GPx) diminuaient avec l’augmentation de la concentration de Cd et le temps d’exposition prolongé dans ces organes de la crevette A. edulis. Des dommages importants de l’hépatopancréas d’A. edulis ont été remarqués à des concentrations plus élevées de Cd, montrant des dommages comme la disparition des limites des cellules épithéliales, le détachement des cellules de la lamine basale, gonflement cellulaire, nécrose, etc. En conclusion, le Cd a causé des dommages oxydatifs en réduisant les activités des enzymes antioxydantes et en endommageant la structure tissulaire dans les principaux organes de la crevette A. edulis. Pour les POP mesurés, la distribution spatiale a montré que la proximité des sources pollution était le plus important facteur déterminant pour la distribution de ces contaminants, montrant des concentrations plus élevées dans les échantillons prélevés près des parcs industriels. Les rapports des HAP analysés ont permis de déterminer l’existence d’intrants pyrolytiques et pétrogéniques. Les PCB Aroclor 1016 et 1260 étaient les principales sources près de la zone industrielle, avec des entrées de DDT montrant un ajout récent à la zone. L’étude globale a révélé un risque limite pour les organismes benthiques. Dans le cas d’E. affinis, la toxicité aiguë de CL 50 % (96h) pour l’exposition au plomb (Pb) était de 431,99 µg/l chez les mâles présentant une sensibilité inférieure à celle des femelles avec 394,27 µg/l. Les plus faibles effectifs totaux de la population ont été observés durant la deuxième génération (F1) pour tous les traitements d’exposition et, par conséquent, la mortalité a augmenté dans cette génération. La plus forte bioaccumulation des métaux dans le copépode E. affinis était également plus élevée dans cette génération ; la fécondité et la survie semblaient donc liées à la bioaccumulation des métaux lourds et concluaient que la sensibilité ou la fitness d’E. affinis était directement liée à l’accumulation de métaux traces. Le pourcentage de mâles était moins élevé dans le traitement des sédiments que dans celui des métaux lourds et des témoins. Cette observation peut indiquer légèrement les différentes façons dont les copépodes sont sensibles aux métaux lourds et aux sédiments en suspension lorsqu’ils sont exposés pendant plusieurs générations. / The present thesis constitutes two major sections, the first deals with macro crustaceans, mud shrimp Austinogebia edulis and the second with micro crustaceans, the copepod Eurytemora affinis. The objectives were to 1. Explore the role of A. edulis as an ecological engineer, 2. Effects of Cadmium (Cd) on oxidative enzymes and morphology in A. edulis, 3. To assess the spatial and temporal variation of persistent organic pollutants (POPs) in the natural habitat of A. edulis, 4. To explore the effect of combined heavy metals to E. affinis and to depict the effect of sediment in re-suspension to E. affinis by following a multigenerational approach. For the first objective, we highlight the significant differences between burrow walls and burrow lumen. The burrow wall of A. edulis showed low permeability and increased sheer strength. Statistically, a significant difference was noticed in the comparison between the sediment composition of the burrow wall and the background. The burrow wall consisted of a 24 times higher organic matter content than one individual of mud shrimp. Thus, they transform the sediment characteristics as an ecological engineer, which is expected to have a significant ecological impact on the ecosystem. Furthermore, on exposure to Cd the antioxidant enzyme (SOD, CAT, and GPx) activities decreased with increasing Cd concentration and extended exposure time in these organs of A. edulis. Significant damage of the hepatopancreas of A. edulis was noticed at higher concentrations of Cd, showing damages like the disappearance of epithelial cell boundaries, detachment of cells from the basal lamina, cellular swelling, necrosis, etc. In conclusion, Cd caused oxidative damage by reducing the activities of antioxidant enzymes and by damaging the tissue structure in major organs of A. edulis. For the measured POPs, the spatial distribution showed that the proximity to sources was the most important determining factor for the distribution of these contaminants showing greater concentrations in samples collected near the industrial parks. The analyzed PAH ratios determined an existence of both pyrolytic and petrogenic inputs. PCBs Aroclor 1016 and 1260 were the main sources near the industrial zone, with DDT inputs showing recent addition to the area. The overall study reflected a borderline risk to the benthic organisms. For E. affinis, the acute toxicity LC 50% (96h) for the exposure of Lead (Pb) was found to be 431.99 µg/l for males showing lower sensitivity than females with 394.27 µg/l. The total population became lowest in the 2nd generation (F1) for all the exposure treatments and also the mortality increased in this generation. The bioaccumulation of metals in the copepod E. affinis was also higher in this generation; thereby fecundity and survival appeared to be linked to the bioaccumulation of heavy metals and concluding that the sensitivity or fitness of E. affinis was directly connected to the trace metal accumulation. The percentage of males was less in the sediment treatment than the heavy metal and control. This observation can slightly indicate the different ways of copepod sensitivity to heavy metals and sediment in re-suspension when exposed for multiple generations.

Thesis (M.S.) in Marine Biology -- University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 46-50).

Thesis (M.Sc.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 116-125.

Background: The blue mussel, Mytilus edulis L., is an important contributor to the shellfish sector of Scottish aquaculture, with 7,270 tonnes worth £8.8 million being produced for the year 2015. Since 2010, production values have fluctuated as a result of inconsistent spat settlement, several business closures, and heightened levels of marine toxins in some areas. On Scotland’s west coast, some farms (most notably Loch Etive) have suffered production losses from the appearance of non-marketable mussels with particularly fragile shells and poor quality meat. Recent research has demonstrated that these undesirable traits have a genetic factor, linked to the presence of a non-native but related species Mytilus trossulus (Gould, 1850) and often its hybrids with the native M. edulis. M. trossulus has been classed as a commercially damaging species under Scottish law, but there is insufficient data on hybridisation and introgression patterns in Scottish mussel populations to evaluate any possible impacts this could have on production. Existing research has focused on single locus genotyping to identify Mytilus spp. and their hybrids in Scotland. By instead utilising multilocus genotyping, introgression could be identified and a better understanding of population structure could be gained, with implications for management to maintain productivity and profitability. The aim of the research presented here was to develop and validate a suite of new species diagnostic markers for multilocus genotyping of field populations of Scottish mussels, thereby establishing a more complete picture of the taxonomic relationships between species than previous studies have permitted. Results: Analysis of SNPs identified with RADseq confirmed the presence of three genetically distinct Mytilus species in Scotland: M. edulis, M. galloprovincialis and M. trossulus. RADseq and KASP genotyping technology successfully identified and validated a suite of 12 highly robust diagnostic SNP markers for multilocus genotyping of Mytilus mussel populations. These markers permitted more comprehensive genotyping than previous studies had, allowing presumed pure species individuals to be distinguished from first generation (F1) hybrids and introgressed (FX) genotypes in reference populations, and subsequently presented the possibility of exploring introgression in a wider scale study. Multilocus genotyping of mussel populations from around Scotland revealed widespread introgression of M. edulis with both M. galloprovincialis and M. trossulus. No pure M. galloprovincialis was identified and pure M. trossulus was restricted to a single site in Loch Etive, possibly part of a relict population. F1 hybrids between M. edulis and M. trossulus were identified in Loch Etive and in Loch Fyne on the west coast. This was evidence of ongoing hybridisation and suggested an active hybrid zone existed in Scotland, something that previous single locus genotyping studies had not acknowledged. A link between shell fragility and M. trossulus introgression was recognised at a single site outside of Loch Etive, but this was not apparent anywhere else and the actual causes of shell fragility remain unevaluated. There was a clear difference between the genetics of most farmed stock and wild populations, which indicated an anthropogenic effect on introgression and subsequent species composition, and had implications for future farm site selection and broodstock sourcing. Temporal species composition in Loch Etive differed over a short time period, but high proportions of M. trossulus alleles were observable some 25 months after a major fallowing event had taken place. Pure M. trossulus was also identifiable, which was consistent with the presence of an established population of M. trossulus existing in this area. Conclusion: Multilocus genotyping has produced a more in depth picture of species diversity in Scottish mussel populations. SNP assays revealed widespread introgression between three genetically distinct species – M. edulis, M. galloprovincialis and M. trossulus – and furthermore recognised that, to date, single locus genotyping has overestimated the abundance of pure Mytilus mussels in Scottish waters. However, this hitherto unidentified genetic complexity does not appear disadvantageous to mussel production, despite the prevalence of M. trossulus introgression among farmed populations, and it is somewhat unlikely that genetics are the sole cause of undesirable shell characteristics among Mytilus spp. mussels.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-06-07T13:31:34Z No. of bitstreams: 1 texto completo.pdf: 2953489 bytes, checksum: e27c4a2febab7908bf620dcad47424ff (MD5) / Made available in DSpace on 2017-06-07T13:31:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2953489 bytes, checksum: e27c4a2febab7908bf620dcad47424ff (MD5) Previous issue date: 2005-09-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Atualmente, o TDZ é conhecido como indutor morfogênico, atuando como um substituto de auxinas e citocininas, na embriogênese e organogênese em várias espécies. Com base no exposto, foram realizados estudos com explantes hipocotiledonares cultivados em meio com adição de TDZ e BAP, e sem combinação entre os mesmos. Na primeira e segunda fases, avaliou-se a influência da posição do explante, da polaridade fisiológica e da orientação dos explantes no meio de cultura. Na terceira fase, avaliou-se o potencial do TDZ, como indutor da embriogênese em segmentos hipocotiledonares do maracujazeiro. No final dos estudos, constatou-se que a resposta morfogênica e a rota morfogênica em segmentos hipocotiledonares de maracujazeiro são dependentes da presença e da natureza química das citocininas adicionadas ao meio de cultura em interação com o modo pelo qual o explante é inserido no meio de cultura; a polaridade fisiológica que se estabelece nos extremos dos segmentos hipocotiledonares, bem como a magnitude desta polaridade, pode ser alterada pela natureza química da citocinina, aplicada ao meio de cultivo, e pela orientação do explante nesses meios. Na presença do TDZ, a polaridade não se estabeleceu; não houve gradiente de resposta morfogênica entre os segmentos. Segmentos hipocotiledonares podem ser induzidos à formação de uma massa de células semelhantes à proembriões e estruturas organogênicas sob influência do TDZ, sendo estas rotas morfogênicas dependentes da concentração deste fitorregulador. / TDZ is known morphogenic inductor acting as auxin and cytokinin on embryogenesis and organogenesis of several species. Based in this statement, several studies were conducted with passion fruit hypocotyledonary explants, cultivated in a medium with TDZ and BAP without combinations. In the first and the second phase of studies the influence of explant position, physiological polarity and explant orientation were studied. In the third phase of studies the TDZ potentiality as somatic embryogenesis inductor in passionfruit hypocotyledonary segments were studied. Finally, it was observed that the morphogenic response and the morphogenic rote in passion fruit hypocotyledonary segments are dependent on the presence and the chemical nature of the cytokinin in the interaction with position, polarity and orientation of the explant. In the presence of TDZ, the polarity did not establish. There have no gradient of morphogenic response among segments. Under the influence of TDZ and depending on the dose of the same the segment can be induced to form cell masses similar to proembryogenic masses or organogenic structures.