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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.
61

Heavy metal competition for acid volatile sulfide binding sites in southeastern coastal sediments

McMahon, Jennifer Nicole 12 1900 (has links)
No description available.
62

Ecological aspects of a semi-enclosed, eutrophic, tropical marine environment

Partlo, John Keith. January 1975 (has links)
No description available.
63

Effects of land-based pollution on Indonesian coral reefs : biodiversity, growth rates, bioerosion, and applications to the fossil record /

Edinger, Evan Nathaniel. January 1998 (has links)
Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (p. 223-258). Also available via World Wide Web.
64

Is reclamation necessary in Victoria Harbour? /

Yuen, Ping-shu, Gomez. January 1900 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 130-135).
65

An implementation evaluation of the No Discharge Area Program in Casco Bay, Maine

Lyons, Regina. January 2009 (has links) (PDF)
These (M.A.)--Tufts University, 2009. / Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (leaves 87-88). Also issued in print.
66

Fouling in the sea water system of the Marine Sciences Research Laboratory, Logy Bay, Newfoundland. --

Sergy, Gary A. January 1972 (has links)
Thesis (M.Sc.) -- Memorial University of Newfoundland. 1973. / Typescript. Bibliography : leaves 70-74. Also available online.
67

The concentration of ten metals in the tissues of shark species Squalus megalops and Mustelus mustelus (chondrichthyes) occuring along the Southeastern coast of South Africa

Erasmus, Christina Petronella January 2004 (has links)
The southeastern coast of South Africa is deemed unpolluted and with the exception of a few localized areas, is believed to be pristine. This study aimed to (1) assess the concentration of metals in the water and sharks (Squalus megalops, Mustelus mustelus) from different sites along the southeastern coast, (2) determine the effects that metals have on each other and investigate the accumulation and storage of metals in different shark tissues, (3) determine the effects of length and sex on metal concentration and the presence of metallothioneins in the liver. Metal concentrations in water from seven sites along the southeastern coast revealed concentrations below the detection limit of the extraction method, except for iron at St. Francis Bay which was below the recommended levels as supplied by DWAF. Met al concentrations in S. megalops from the seven sites revealed significantly elevated levels in individuals from Algoa and St. Francis Bay when compared to the other 5 sites. This was observed for all metals except manganese, which had a higher concentration at Cape Agulhas. After comparing the metal levels in muscle tissue (S. megalops) with data from the Department of Health it was concluded that the sharks caught at Algoa and St. Francis Bay were unsuited for human consumption. Liver and vertebral tissues from both S. megalops and M. mustelus were deemed unsuited for human consumption but further research should be conducted especially on vertebral metal concentrations. Comparing the metal concentration in different tissue types of S. megalops and M. mustelus significant difference were observed and attributed to differences in the maturity (thus age) of the two species. Significant differences in the metal concentration of males and females for both the species were observed. A higher number of differences were however observed in M. mustelus than in S. megalops, most probably due to the differences in maturity. Length and weight vs. metal concentration regressions in the males and females of both species revealed more negative than positive trends. This was found to be in accordance with other studies from around the world. Using the life stages of S. megalops, significant differences in the average concentration of metals were observed between the life stages, with embryos usually having the highest concentration. The metal concentration series determined for S. megalops were similar to that which have been reported in the literature in that iron and zinc occupied the highest concentration positions while cadmium, copper and manganese occupied the last three. The spleen usually had the highest metal concentration except for aluminium in skin and arsenic in muscle tissue. Pearson correlation revealed significant negative correlations between cadmium and the mentioned metals suggesting that cadmium replaces essential metals such as manganese, iron and copper as. Negative correlations between essential metals were observed most probably due to the competition for binding positions on ligands. Positive correlations were observed between metals in sp ecific tissue types and may be indicative of synergistic effects, e.g. aluminium may result in the accumulation of other metals such as cadmium. Positive and negative correlations between a specific metal and different tissue types have also been observed and it appears that there are movement of metals between tissue types. Positive correlation for essential metals between yolk and other tissue have been observed, although no correlations for non-essential metals were observed. This could potentially indicate a mechanism that prevents the accumulation of nonessential metals in embryos. Though no metallothioneins were isolated form the liver, the presence of cadmium in other proteins indicate that that cadmium is substituted for essential metals, and as this may result in deleterious physiological effects, further studies should be conducted. In conclusion it can be said that although some of the results were expected there are still quite a few unanswered question and further studies should be conducted.
68

The potential for microplastics to cause harm in the marine environment

Wright, Stephanie January 2015 (has links)
Plastic debris is an emerging environmental issue, with >10 million tons of plastics debris per annum entering the sea. Exposure to marine conditions facilitates the exponential fragmentation of plastic to micro-sized particles (microplastics). Marine and coastal sediments are a sink for microplastic pollution. Consequently, the ingestion of microplastics by a range of benthic marine invertebrates, including polychaete worms, has been reported in situ. Microplastics are vectors for priority pollutants capable of eliciting adverse health effects. However, the particle and chemical toxicity which microplastics could incur to ecologically-important marine invertebrates is unknown. This thesis aims to determine the potential for microplastics to cause harm in the marine environment, with a focus on benthic polychaete worms. Specifically, it assesses the potential particle toxicity which could arise from chemical-free microplastics; and the potential chemical toxicity which could arise from leached endogenous chemical additives or sorbed chemical pollutants. To address these, an integrative approach was employed, primarily using laboratory-based whole-sediment in vivo exposures, established cellular and whole-tissue toxicity assays, and analytical chemistry. For the first time, this thesis reports that chemical-free microplastics cause particle toxicity in the lugworm Arenicola marina. Feeding activity was reduced during exposure to 5% microscopic unplasticised polyvinylchloride (UPVC) by sediment weight, whilst exposure to ≥1% UPVC by sediment weight significantly reduced energy reserves relative to control animals. Evidence for the transfer and toxicity of endogenous additives from PVC to lugworms is provided. Lugworms exposed to 1% PVC by sediment weight exhibited a 70% increase in additive concentration, coinciding with inhibited mucus production and enhanced lipid reserves and oxygen consumption, compared to control lugworms. Ragworms (Hediste diversicolor) exposed to leached toxicants from bioplastic cigarette debris were found to exhibit significantly longer burrowing times, >30% weight loss, and >2-fold increase in DNA damage compared to control ragworms. Bio-concentration factors for nicotine – the biomarker of exposure - were 500 fold higher from leachates in seawater than from microfibres in sediment. Overall, this thesis provides evidence to suggest that the incorporation of microplastics into marine sediments can significantly impact the health of marine polychaete worms due to both particle and chemical effects. This emphasises the need to reconsider the classification of plastic as non-hazardous and questions whether we as humans are also at risk.
69

Liability for marine pollution by ships

Young, Charles A. January 1976 (has links)
One aspect of the international problem of marine pollution is pollution by ships. As an international problem, pollution by ships demands action at a level above the national. Many international agreements have been reached, but this thesis argues that a comprehensive liability regime is now necessary. To find the principles upon which such a liability regime should be based, decisions of international tribunals, acts of state practice, and existing conventional arrangements are canvassed. "Reasonableness" is found to be the central characteristic, and is given more specific meaning through the survey. A convention is proposed in general outline only, but a regional framework is suggested, and principles on which to base the convention are summarized. / Law, Peter A. Allard School of / Graduate
70

Ecological aspects of a semi-enclosed, eutrophic, tropical marine environment

Partlo, John Keith. January 1975 (has links)
No description available.

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