• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 24
  • 12
  • 12
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 71
  • 71
  • 17
  • 14
  • 14
  • 13
  • 12
  • 12
  • 10
  • 9
  • 9
  • 9
  • 8
  • 7
  • 7
  • 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.
11

Ecology of the Mary River Turtle, Elusor macrurus

Flakus, S. P. Unknown Date (has links)
No description available.
12

The fishing business and the business of fishing

Taylor-Moore, N. Unknown Date (has links)
No description available.
13

Protecting the Diversity of the Depths: Strengthening the International Law Framework

Warner, Robin Margaret Fraser January 2006 (has links)
Doctor of Philosophy(PhD) / It is only in recent decades that marine scientific research has begun to reveal the true physical characteristics and resource potential of the open ocean and deep seabed beyond national jurisdiction. A combination of factors such as the depletion of inshore fish stocks and an increase in global maritime trade has led to greater usage of the vast maritime area beyond the territorial sea and exclusive economic zone limits of the coastal states. Human activities in this area of the ocean, which covers approximately 50% of the world’s surface, have expanded to include bioprospecting, exploration for deep seabed minerals, more sophisticated marine scientific research and deep sea tourism. This rise in human activities beyond the offshore zones of coastal states poses actual and potential threats to the physical characteristics and biodiversity of the open ocean and deep sea environments. Arbitrary human intrusions into this largely unexplored marine domain have the potential to harm the intricate links between complex marine ecosystems and to erode components of marine biodiversity. This thesis examines the global and regional provisions which have been put in place to regulate the environmental impacts of human activities that occur beyond national jurisdiction. An analysis of these instruments and their implementation reveals that the current international law framework provides only minimal levels of protection for the marine environment beyond national jurisdiction. It explores several options based on the 1982 United Nations Convention on the Law of the Sea (LOSC) and the 1992 Convention on Biological Diversity (CBD) to establish a cohesive environmental protection system for the marine environment beyond national jurisdiction.
14

Load Bearing Structural Elements of Glulam in Marine Environment : A literature and case study / Bärande konstruktionselement av limträ i marin miljö : En litteratur- och fallstudie

Karin, Abrahamsson January 2020 (has links)
This thesis discusses the possibilities of using glued laminated timber as load bearing structural elements in structures in close vicinity of saltwater. Glued laminated timber, also referred to as glulam, is a refined timber product constructed of timber lamellae that are glued together. The thesis contains a literature study and a case study that covers glulam beams in a pedestrian jetty located on the Swedish west coast. The literature study addresses wood in relation to moisture, the effects that salt may have on wood in a marine environment, wood decaying mechanisms and suitable wood preservatives to prevent decay. The literature study also covers glulam as a material and the possibilities of wood pressure impregnation. A method of estimating the service life of timber elements is also discussed.   The results of the literature study were applied in a case study of a specific case, to explore the possibility of replacing the current steel beams of the structure with glulam beams. From the case study, the strength and deflection of the prospective glulam beams were calculated. Service life of the prospective glulam beams was estimated based on the environment they would be exposed to. An analysis of the market for glulam products in Sweden was also performed to find out what dimensions and wood impregnation classes are available.   The results of the literature study show that glulam can be used as main load bearing elements in a marine environment, given that the structure is placed above sea level. Salt water does not affect the wood, rather it works as a wood preservative and gives some protection against rot. However, the structure is subjected to high moisture content and pressure impregnation is necessary. The high moisture content also affects the mechanical properties of the wood as the strength and stiffness of glulam decrease with increasing moisture content. Creep of the material is also affected as it increases with increased moisture content.   Regarding strength and deflection, the results of the case study show that glulam beams available on the Swedish market are of sufficient dimensions to be used. Regarding service life, the case study showed that the estimated service life of the glulam beams is only 19 years, but the service life required is 50 years. The current structure design with prospective glulam beams does not meet the requirements for durability of the material. However, suitable design changes regarding wood moisture protection could increase service life of the glulam beams. / Denna rapport behandlar möjligheterna till att använda tryckimpregnerat limträ som huvudbärverk i konstruktioner i nära anslutning till saltvatten. Limträ är en träprodukt bestående av trälameller som limmats samman till större träelement. Rapporten består av en litteraturstudie och en fallstudie som behandlar limträbalkar i en promenadbrygga belägen på den svenska västkusten. Litteraturstudien avhandlar trä i förhållande till fukt, eventuell påverkan av salt i en marin miljö, nedbrytningsmekanismer för trä samt lämpliga träskydd för att förhindra nedbrytning. Litteraturstudien behandlar även limträ som material och möjligheterna till tryckimpregnering. En metod för att uppskatta livslängden av trä diskuteras också.    Resultaten från litteraturstudien applicerades i en fallstudie för ett specifikt fall, för att undersöka möjligheterna att ersätta den nuvarande konstruktionens stålbalkar med limträbalkar. Utifrån fallstudien beräknades hållfastheten och nedböjningen av de tilltänkta limträbalkarna. Livslängden på de tilltänkta limträbalkarna uppskattades baserat på den miljö de skulle komma att utsättas för. En analys av marknaden av tryckimpregnerade limträprodukter i Sverige genomfördes också för att se vilka dimensioner och tryckimpregneringsklasser som finns att tillgå.   Resultatet från litteraturstudien visar att limträ kan användas som huvudbärverk för marina konstruktioner med kravet att konstruktionen placeras ovanför vattenytan. Saltvatten påverkar inte träet negativt utan verkar snarare som träskydd mot röta. Dock utsätts konstruktionen för hög fuktkvot och måste därför tryckimpregneras. Det höga fuktinnehållet påverkar även de mekaniska egenskaperna av träet då hållfastheten och styvheten av limträet minskar med ökande fuktkvot. Krypningen av träet påverkas också, då krypning ökar med ökad fuktkvot.   Med avseende på hållfasthet och nedböjning visade resultatet av fallstudien att tryckimpregnerat limträ som kan erhållas från den svenska marknaden är av tillräckliga dimensioner för att kunna användas. Avseende livslängd visade fallstudien att den undersökta konstruktionens estimerade livslängd endast är 19 år. Dock är den erfordrade livslängden för träkonstruktionen 50 år. Dagens konstruktion möter inte kraven på materialets varaktighet, men längre livslängd skulle kunna erhållas genom lämpliga designändringar avseende limträbalkars skydd mot fukt.
15

Mineral absorption by submerged bone in marine environments as a potential PMSI indicator

Mammano, Kristina Lynn 24 February 2021 (has links)
Human remains enter marine environments in a number of ways ranging from homicides, suicides, accidental drownings, shipwrecks, to burials at sea. Once the remains are discovered, a legal and forensic investigation begins. A key component to this investigation is the postmortem submergence interval (PMSI). Determining this range on skeletonized remains is a complicated process in which there is no accurate test; although barnacle growth data was previously used to determine PMSI, there are still limitations with that method. Therefore, a more reliable component of bone needs to be used as a potential PMSI indicator, such as its elemental composition. Diagenesis starts affecting bones immediately and continues for thousands of years. Although diagenesis is a slow process, an exchange of elements between bone and the marine environment continually occurs. The purpose of the present study is to determine whether an increase in marine elements is found within the composition of bone after being submerged in a marine environment for up to 20 months. The present study will also determine whether bones submerged in different aquatic environments have significantly different elemental concentrations. For the time trials, pig femora were submerged in lobster cages off the coast of the University of Massachusetts Boston for 2-20 months. For the salinity trials, pig femora were submerged in a freshwater pond (Holliston, MA), the Inner Boston Harbor, and an ocean inlet near Woods Hole, MA for 18 months. All bone samples were dried, milled, homogenized, and analyzed by ED-XRF under He purge. The initially produced mass percentages of the identified elements were corrected with certified values of standard reference materials (NIST 1486, 1646a, and 2702). A Pearson’s correlation test determined that the concentrations for K, Fe, Zn, Sr, Si, S, Cr, Mn, Cl, Br, Ta, and W were significantly correlated to the amount of time submerged in the water. An ANCOVA analysis was applied to the significant elements noted above. After adjusting for the amount of time submerged, the concentrations of K, Fe, Sr, Si, S, Cl, Br, and Ta were determined to be significantly different between the control samples (never submerged) and the submerged samples (submerged for 2-20 months). K was the only element that had greater concentrations in the control samples than the submerged samples, most likely because of the decrease in mass percent as other environmental elements were incorporated into the bone. S and W were significantly related to the number of months submerged, with S being positively influenced and W being negatively. A multivariable linear regression was run in order to identify a means of predicting the amount of time submerged from the elemental concentrations of an unknown bone from a marine environment. The regression produced an equation that used the concentrations for K, Sr, Si, S, Cr, Cl, and Br to predict the PMSI in months. For the salinity trials, a one-way ANOVA was performed on all the elemental concentrations from the different salinity environments. Post hoc tests determined significant differences in elemental concentrations for K, Fe, Si, S, Al, Ti, Cr, Ni, Mn, Cl and Br among the different submergence locations; elemental concentrations of S, Fe, Mn, Cl, K, and Br were either significantly different between the fresh, brackish, and saltwaters or the freshwater and some form of marine water (brackish and salt). The trends in the other elemental concentrations were less obvious due to the impact of pollution within the surrounding environments. The linear regression equation created in the present study accounted for the majority of the variance in the outcome (R2 = 80.2%); however, this equation should not currently be applied in forensic investigations. The study needs to be repeated a number of times with other bone samples from the same and different submergence locations, in order to determine the accuracy and usefulness of the equation. Although not verified, this regression equation may be useful in analyzing samples from brackish and saltwater environments, because the majority of the variables within the equation (K, Sr, S, Cl, Br) were consistent among the fresh, brackish, and saltwater samples. Time constraints, small sample sizes, and variance among samples were the major limitations of the present study. Even with limitations, significant results were produced by the ED-XRF analysis. Future research should expand upon the methodologies of XRF analyses of bones, especially those from marine environments. Because of their relevance to forensic investigations and PMSI, future research should include longer experimental periods, more salinity locations, more information on the surrounding water components, and more comparisons among instrumentation.
16

Screening of marine bacteria as a source of bioactive secondary metabolites

Mhlongo, Jatro Kulani January 2021 (has links)
>Magister Scientiae - MSc / Marine invertebrate associated (MIA) bacteria are an important source of bioactive secondary metabolites with the potential to address the current anti-microbial resistance crisis experienced globally. Secondary metabolites (SM) have historically yielded several compounds with pharmaceutical applications such as anti-viral, anti-microbial, anti-cancer, anti-inflammatory and anti-parasitic. This study aimed to use bioassay and genomic approaches in the identification of MIA bacteria isolated from South African marine invertebrates as a source of bioactive compounds and the characterisation of the produced SMs using analytical techniques. A total of 23 MIA bacteria were cultured under different conditions (one strain many compounds approach (OSMAC)) to evaluate their ability to produce anti-microbial compounds against a panel of indicator strains namely Escherichia coli 1699, Bacillus cereus ATCC10702, Pseudomonas putida ATCC12633, Mycobacterium aurum A+, Staphylococcus epidermidis ATCC14990, Aspergillus fumigatus MRC and Candida albicans NIOH.
17

Nouvelles méthodes de détection de virus dans l'environnement : application à l'identification de nouveaux virus géants dans le milieu marin.

Arslan, Defne 24 November 2011 (has links)
L’objectif de cette thèse était d’isoler de nouveaux Mimiviridae dans l’environnement marin à l’aide d’amibes, hôtes potentiels de ces derniers et surtout organismes ubiquistes phagocytaires et connus pour être parasités par des microorganismes pathogènes. Après la mise en place et la validation de protocoles d’échantillonnages et de mise en culture de prélèvements environnementaux, plusieurs échantillons ont été analysés. Un nouveau membre de la famille des Mimiviridae a été isolé à partir d’un échantillon marin côtier provenant du Chili, stocké dans un milieu enrichi en amidon (milieu riz, propice à la conservation voire à la production de virus) puis mis en coculture dans une souche d’amibe Acanthamoeba griffini. Le séquençage de son génome révèle 1260 kb, codant pour 1120 protéines putatives, ce qui en fait le plus grand génome viral connu. Nommé megavirus chiliensis, sa capside est icosaédrique et possède également des fibrilles comme Acanthamoeba polyphaga mimivirus tout en étant plus grande (diamètre apparent 520 nm vs 450 nm). Bien que les morphologies des deux virus soient similaires et que de nombreuses particularités de mimivirus soient conservées chez megavirus (stargate), 23 % des protéines de megavirus n’ont pas d’homologues chez mimivirus, et les 594 gènes orthologues partagés présentent une identité résiduelle moyenne de 50 %. De plus, megavirus présente 3 amino-acyl-ARNt-synthètases supplémentaires (IleRS, TrpRS et AsnRS) à celles de mimivirus. Ces résultats suggèrent que ces deux virus sont issus d’un génome cellulaire ancestral qui a évolué par réduction génomique. Un parasite intracellulaire obligatoire a également été isolé à partir d’échantillons de sédiments marins de la côte chilienne. Des observations au microscope électronique à transmission indiquent une forme ressemblant à une endospore, de taille très variable (de 400 nm jusqu’à 1 μm), avec une paroi multicouche épaisse (~60 nm) et un pore apical. Cependant, aucune évidence de division n’a encore été observée, laissant penser que cette entité capable de multiplication pourrait être un virus, sans ressembler aux morphologies connues à ce jour. / In order to isolate new Mimiviridae from the marine environment, we used amoeba -ubiquitous phagotrophic protozoa - as potential host for these viruses. Different sampling protocols were tested and validated before carrying out co-cultures with amoeba and environmentals samples. A new Mimiviridae giant virus was isolated from Chilean coastal seawater completed with rice media (enriched incubation). Produced in Acanthamoeba griffini, its genome sequence has 1,260 Mbp and encodes for 1120 putative proteins, making it the largest known viral genome and thus named Megavirus chiliensis. Its icosaedral capsid is covered with fibrils and its size is bigger than that of Acanthamoeba polyphaga mimivirus (520 nm vs 450 nm). Although both virions are very similar and most of the mimivirus idiosyncrasies are conserved in megavirus (stargate), 23 % of megavirus putative proteins have no mimivirus homologs. Both viruses share 594 orthologous proteins exhibiting an average identity of 50 %. Moreover, megavirus contains 3 additional amino-acyl tRNA synthetases (IleRS, TrpRS and AsnRS) compare to mimivirus. These results suggest that these viruses have evolved from an ancestral cellular genome by reductive evolution. In addition, an amoeba obligatory intracellular parasite was isolated from marine sediments from Chilean coast. Transmission electron microscopic images show a particule like endospore with variable size (from 400 nm to 1 µm), a multilayered outer wall (~60 nm) and an apical pore. No evidence of division was observed, suggesting that the multiplication of this endoparasite occurs without division, suggesting that it could be a virus without any similarity to those described today.
18

Heavy Metal Contamination from Landfills in Coastal Marine Sediments: Kiribati and New Zealand.

Redfern, Farran Mack January 2006 (has links)
Landfill leachates are a concern in the Pacific Region where they may contribute contaminants to the coastal marine environment. Poor waste management and pollution of coastal waters are amongst the major environmental problems in Kiribati, particularly in South Tarawa. An investigation of areas adjacent to coastal landfill sites; Betio, Kiribati and Auckland, New Zealand was undertaken. The Kiribati case study investigated metal contamination in marine sediments at an operational landfill while the New Zealand study was adjacent to a coastal landfill decommissioned in the 1970s. Surficial sediments (top 15 cm) were collected along transects. At both the New Zealand and Kiribati sites, 3 transects adjacent to the landfill and 1 control transect were sampled. The sediments were analyzed for particle size distribution, organic matter content, and Cd, As, Cr, Cu, Pb, Hg, Ni and Zn concentrations. The pH was also measured. The Kiribati study site had a groundwater pH of 7.14 - 8.85, and sediment materials were dominated by sand with a low organic matter content (1.60 - 2.21 %). At the Kiribati sites Cd, As, and Ni were below the detection limits. The Cr, Cu, Pb and Zn concentrations were lower at the Kiribati control transect than the landfill transects. Cr level decreased away from the landfill indicating the landfill as a possible source. However, Cu and Zn did not show any distribution pattern suggesting other potential sources (port and shipwrecks) may have contributed to the elevated levels. At the Kiribati landfill and control transects the Cr, As, Cd, Cu, Pb, Ni, and Zn concentration were below the Effects Range-Low (ERL) and the threshold Effects levels (TEL) of the Sediment Quality Guidelines (SQCs) of the National Oceanographic and Atmospheric Administration (NOAA) and the Florida Department of Environmental Protection, indicating no potential adverse ecological effects on the biota. At the Kiribati control site the Cr, As, Cd, Cu, Pb, Ni and Zn concentrations were within the background ranges published for clean reef sediment but the concentration at the landfill transects exceeded the background ranges. The concentration of mercury at both the control and landfill transects in Kiribati exceeded the Effects Range-Median (ERM) and the Probable Effects Level (PEL) of the SQGs indicating potential adverse ecological effects on the local benthic communities. The New Zealand study site sediments had a pH of 6.22 - 7.24, and comprised up to 90 % clay/silt, with an organic matter content of 5 - 22 %. At the New Zealand landfill transects Arsenic concentrations decreased away from the landfill indicating the landfill as a possible source. Other metals such as Cr did not show a pattern of distribution along the transects, or with depth, suggesting that the landfill was not the only source of these metals. There was a weak correlation between organic matter content, particle size distribution, and metal enrichment. At the New Zealand site, there were no marked differences in metal concentrations between the landfill and control transects suggesting the landfill was not the only source of metals and that the wider urban or industrial run-off may have contributed. All the metal concentrations, except Hg and Zn, exceeded the ERL and the TEL values indicating the potential for adverse ecological effects of metals on the benthic communities. At the New Zealand site the Hg and Zn concentrations exceeded both the ERM and PEL of the SQGs and are considered highly contaminated.
19

Oil Spills in New Zealand's Territorial Waters: Fence at the Top of the Cliff?

Hoeberechts, Veronica Anne January 2006 (has links)
Over the last four decades, there have been many catastrophic oil spills in the marine environment and these larger oil spills have often caused environmental devastation especially if they occurred in the coastal marine area. Serious ecological damage can also be caused from operational discharges, ballast and bilge water, from ships within territorial waters. Until now New Zealand has only had relatively minor oil spillages in its coastal waters, primarily from ships' discharge or accidental leaks in port. The possibility however of a major oil spill occurring within our coastal area is considerably higher today than 20 years ago as there has been a significant increase of all types of oil tankers/bulk carriers/container ships to New Zealand. New Zealand is an island nation that relies heavily on the marine environment for commercial operations such as fisheries and tourism and many New Zealanders enjoy recreational, aesthetic and spiritual ties to the coastal marine area. The sustainability of our territorial sea is therefore of paramount importance. A major oil spill could cause widespread ecological damage, cripple or destroy marine/tourism operations and ensure that the human values associated with the coast are lost, possibly for many years. The research reported here addresses the issue of oil spill preparedness and response in New Zealand's waters. A combination of a review of New Zealand's international commitments and domestic legislation and two case studies of high profile oil spills: the Poor Knights Islands Marine Reserve and the Jody F Millennium are used. The research identifies whether the present environmental legislation, that promotes sustainable management, is proactive in the prevention of a major oil spill and concludes that the New Zealand approach reflects a relatively strong Sustainable Imperative position rather than one of Sustainable Development. In implementation it relies heavily on co-management integrated at the regional council level.
20

The Impact Assessment of Environmental Quality and Social Development at Formosa Petrochemical Corporation(FPCC) NO.6 Naphtha Cracking Industry Site.

Lin, Chih-hung 08 September 2009 (has links)
The Formosa Petrochemical Corporation (FPCC) has operated the No. 6 Naphtha Cracking industry site at Mailiao of Yunlin County for 14 years since it completed the construction in 1995. Although the plant were assessed according to the process of environmental impact assessment as required by government¡¦s guidelines before the approval of FPCC establishment at the site, there is a need to re-evaluate the site strictly for problems resulting from the industry activities over the year. The present study is initiated to research and assess the environmental monitoring data collected over the years to determine the spatial and temporal trend of heavy metal contaminants associated with the FPCC operation at site and its coastal areas. The data information used in this study consist of government annual survey reports with regard to the oceanography data of the site, seawater, sediment, and air quality. The FPCC¡¦s monitoring data are also evaluated for including in the environmental quality assessment of Mailiao coastal areas. The present study employed the annual total contaminant discharges reported by the FPCC for obtaining the total burden emitted into the nearby counties Taihsi and Lunbei. The results showed that the coastal marine environment around the industrial site and the Jhuoshuei River have major immediate impacts and problems from the activities. The results of sediment metal content have substantial increase over the years, although the value of metal concentrations is proclaimed that it is within the government provisional guidelines of sediment contaminant standard. In the current circumstance, there are no standard criteria for sediment metal concentration in the marine environment reported elsewhere in the world with exception of Canada. The air quality results showed that Lunbei which is located east side of FPCC site have a decreasing trend of contaminant discharge compared with Taihsi which is located at southern side of FPCC site have a increasing trend of contaminant discharge. Nevertheless, the FPCC site have an increasing total annual discharge. The present study also conducts a survey at Mailiao and Taihsi residences on the social-economic development and the influence associated with the FPCC operation. The survey consists of all stakeholders such as government municipality official, marine aquaculture farmers, non-government organization and fishery cooperation representatives. They are concern the influence on the social-economic development and environment impact from the industry operation. These include the problems of low spat rating in oyster farming and dust falling into the marine farm site to cause the death of bivalves. The health of local residences from FPCC site is of concern due to the expansion program of plan to the site. The present work shows the change and alteration of marine environment resulting from the FPCC activities that have worsened the sustainability development of coastal area.

Page generated in 0.1146 seconds