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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.
1

Ecophysiological adaptations of northeast Pacific kelp communities to ultraviolet light stress

Swanson, Andrew Keith. January 2000 (has links)
Thesis (Ph. D.)--Simon Fraser University, 2000. / Includes bibliographical references (p. 139-155).
2

Combined fields (electro-osmosis and pressure) dewatering of kelp

Lightfoot, Dennis G. (Dennis George) January 1991 (has links)
The world's brown marine algae, or kelps, have a great potential for agricultural use. Over 14 million tonnes of kelp are estimated to be available for harvesting every year, but only 6.3% is harvested, mostly for food products or alginate extraction. The inclusion of kelp in an animal's ration has been found by several researchers to have a beneficial effect on the animal's health and productivity. High concentrations of kelp in an animal's ration, however, can have detrimental effects on the animal's health due to toxic levels of certain inorganic salts. / By including a dewatering operation in the production of dried kelp meal, much of the soluble salts present in the kelp will be removed with the filtrate. The filtrate would also be valuable as a source of potassium, trace minerals, and phyto-hormones for crops. Energy costs for dewatering are also much lower than for drying. Because kelp is difficult to dewater using conventional methods, a combined fields technique using electro-osmosis and mechanical pressure was investigated. / Electric current and pressure were both found to have a significant positive effect on dewatering. Dewatering resulted in significantly lower ash and available carbohydrate fractions, while having no other significant effect on kelp meal composition. The combined fields dewatering resulted in significant total energy savings over conventional dewatering or drying alone. / The combined fields dewatering process was successfully scaled up to a continuous process using a prototype roller press. The press was able to produce a press cake with up to 32% solids. The continuous process resulted in significantly lower ash content and significantly higher protein. The total energy to produce kelp meal with the roller press was found to be about half of the energy required for drying alone.
3

Genetic and morphological variation in Macrocystis C. Agardh (Laminariales, Phaeophyceae) off the North American coast

Mackenzie, Ian M. January 1997 (has links)
Thesis (M.S.)--Simon Fraser University, 1997. / Includes bibliographical references (leaves 70-78).
4

The potential influence of kelp exudates produced at large-scale kelp cultivation sites on microplankton assemblages

Campbell, Iona January 2016 (has links)
With the global drive to find a renewable liquid fuel, attention has turned to macroalgae cultivation as a feasible approach for the production of a third generation biofuel. Additionally, the increasing demand for macroalgal extracts, and growing interest in their bioremediation role at aquaculture sites in an Integrated Multi-Trophic Aquaculture (IMTA) system, is driving the expansion of macroalgae cultivation across Europe. The suitability of kelp species to a large proportion of the European coastline, combined with high carbon, high value extract content and well-established cultivation techniques already demonstrated in Asia, makes them strong candidates for the expansion of macroalgae cultivation. Although large-scale kelp cultivation in Europe is still in its infancy, it is essential we understand the ecological impacts that such largescale sites may have on economically important coastal waters, before extensive production goes ahead. This thesis highlights the link between dissolved inorganic and organic matter exuded by candidate European kelp cultivation species Saccharina latissima and the microplankton assemblages. Laboratory incubation experiments using kelp exudates and microplankton were compared to fieldwork carried out at the world's largest kelp cultivation site in Rongcheng, China. Small-scale incubations have shown that resources in kelp exudates can be utilised by the bacterioplankton and mixotrophic Harmful Algal Species (HAS) of phytoplankton, and fieldwork at a working large-scale Asian kelp cultivation site, provides significant evidence impact of kelp cultivation on the bacterioplankton assemblage. Kelp exudates at large-scale cultivation sites will influence the microplankton assemblage, and this research is the first evidence of the impact that large-scale coastal aquaculture of kelp can have on bacterioplankton assemblages. A large knowledge gap in current fish, shellfish, invertebrate and IMTA aquaculture systems exists in understanding the fate of waste at cultivation sites in the microbial food web. Understanding the role of the microbial loop in aquaculture will be essential in managing the sustainability of aquaculture in an era of global expansion.
5

The life history and distribution of Macrocystis in British Columbia coastal waters

Scagel, Robert Francis January 1948 (has links)
Only one species, Macrocvatls integrifolia Bory, is present in British Columbia coastal waters. It is found distributed along the whole coast in regions approaching open ocean conditions, but protected against the full ocean force, where the seawater has a specific gravity of over 1.018 at 15 degrees Centigrade and where a suitable rocky bottom, between three feet above to twenty feet below zero tide level, is available. The method of growth of the sporophyte, which is partly dichotomous and partly unilateral, is fully described from the time it is first discernible to the naked eye up to maturity. Dichotomous and subdichotomous divisions of the basal growth region are responsible for the extensive development and perennial habit of the plant. Active zoospore liberation from mature plants and young sporophytes (single, undivided blade stage) were found at least from July 1 to September but the limits were not determined. The gametophytic stages were not followed. Maximum growth (elongation) of Macrocystis recorded was 3.10" per day for a period of 29 days at the north-east of Vancouver Island. No regeneration from the holdfast or at the cut surfaces of stipes were shown as a result of cutting. Stipes of Macro cystis may continue to grow after being severed from their holdfasts. Plants removed to deeper water are retarded in rate of growth. Various practical aspects of this economically important plant are considered. It is believed two harvests per year are possible if proper precautions are taken with respect to the relative position of the terminal laminae of the plants when harvesting. A method of estimating quantities using the diameter of the stipe as an index is suggested. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate
6

Combined fields (electro-osmosis and pressure) dewatering of kelp

Lightfoot, Dennis G. (Dennis George) January 1991 (has links)
No description available.
7

Photosynthetic response of Scandinavian kelp forests to stratospheric ozone depletion

Miller, Harlan Laurence January 2002 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.
8

The potential and a strategy for managing and developing marine plant resources in British Columbia

Lewis, Kevin M. January 1985 (has links)
This thesis assesses the potential and suggests strategies for the development of marine plant resources on the Canadian west coast. Three sub-objectives have been considered to determine the kind of marine plant management strategies that are necessary to assess and develop the industry in British Columbia. The analytical framework of the thesis hinges on these questions. 1. What is the physical potential for growing and harvesting these marine plants on the Canadian west coast and what products might be produced? 2. What is the potential market for marine plant products and what are the economics of production in British Columbia? 3. What should be the components of a strategy for developing an industry in British Columbia? These objectives have been met through literature reviews and a series of personal interviews. In 1976, the cumulative commercial value of the world's marine plant industries was approaching U.S. $1 Billion. The Japanese domestic industry alone generated an annual value of approximately U.S. $700 Million. World trade in edible marine plants and all marine plant products was estimated at U.S. $140 Million. Of this international trade, phycocolloids (marine plant colloids) and their raw materials constituted the dominant economic share. Since preliminary attempts, in 1946, to develop a marine plant operation in British Columbia the history of the marine plant industry has been one of disappointment. A series of failed development attempts has plagued the industry since its conception. At this time a limited marine plant industry has established on the west coast. These operations are small in scale and rely on the harvest of localized wild and cultured stocks. This study focuses on six marine plant species and identifies kelp meal and roe-on-kelp as economically viable products at this time. A number of small-scale operations have developed around the roe-on-kelp sector but administrative/jurisdictional constraints have prevented the establishment of a commercial scale kelp meal operation. Three priorities for the development of marine plant resources emerge from this study: 1. to provide a process which permits the expression and incorporation of the interests of affected resource users; 2. a need for an implementation process; and 3. a need to reserve critical resource beds to prevent encroachment of unsympathetic activities. The thesis concludes by illustrating that a strategic planning process provides an appropriate procedure to implement these priorities. Recommendations for industrial development and management are discussed under four categories: 1. Who should do the planning and management? 2. What should the co-ordinating body be doing? 3. How to implement the strategic plan? 4. When should these efforts begin? / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
9

NDVI and panchromatic image correlation using texture analysis

Jablonski, David A. January 2010 (has links) (PDF)
Thesis (M.S. in Space Systems Operations)--Naval Postgraduate School, March 2010. / Thesis Advisor(s): Olsen, Richard C. Second Reader: Trask, David M. "March 2010." Description based on title screen as viewed on April 28, 2010. Author(s) subject terms: NDVI, Panchromatic, Texture analysis, Kelp Detection. Includes bibliographical references (p. 69-70). Also available in print.
10

Chemical signaling and defense in brown algal kelps during interactions with herbivores / Signalisation chimique et défense chez les algues brunes en interaction avec leurs herbivores

Cabioch, Léa 15 December 2016 (has links)
Les kelps sont des espèces clés dans les écosystèmes marins tempérés, elles vivent en milieu intertidal le long des côtes où elles sont souvent exposées à des herbivores. Comme la plupart des organismes sessiles, les kelps ont développé des stratégies de défense contre l’herbivorie. Chez la laminaire Laminaria digitata, l’élicitation par les oligoguluronates induit des régulations transcriptomiques et l’activation de voies métaboliques, menant à la production et la libération de métabolites dans l’environnement, tels que des aldéhydes. De plus, cette espèce d’algue brune a montré des réponses systémiques suite à une élicitation. Des composés solubles dans l’eau de mer environnant les forêts de laminaires peuvent aussi modifier leur physiologie en réponse à l’élicitation. Une telle signalisation chimique à distance lors des réponses de défense rappelle les phénomènes de protection systémique et de potentialisation chez les plantes. Dans les forêts de laminaires, celle-ci pourrait jouer un rôle écologique majeur dans la structuration des algues marines et des communautés d’herbivores. Dans le contexte des interactions kelp/herbivores, nous avons étudié les réponses de défense et les processus de signalisation chez deux espèces emblématiques de laminaires originaires des côtes atlantiques et du Pacifique Sud, impliquées dans des interactions spécialisées avec leurs herbivores, L. digitata en interaction avec Patella pellucida (Bretagne, France) et Lessonia spicata avec Scurria scurra (Chili). Des approches combinées de métabolomique et de bio-essais ont été réalisées pour élucider la nature de potentiels signaux chimiques et leurs rôles biologiques et écologiques dans la défense des algues face aux herbivores. Les résultats ont montré que, en réponse à un broutage, les kelps présentent des modifications métaboliques telles que l’induction de voies de biosynthèse des acides gras, des oxylipines et d’acides aminés, ainsi que des modifications transcriptomiques. De plus, nous avons constaté que les laminaires co-incubées avec des algues broutées présentaient des changements de leur endo-métabolome en comparaison à des algues broutées, et semblaient moins consommées lors d’un broutage ultérieur, suggérant une perception et une intégration des composés algaux induits par l’herbivorie par les algues voisines. Des études de terrain et en laboratoire ayant précédemment mis en évidence une libération massive d’aldéhydes dans l’air et l’eau de mer après des stress biotiques et abiotiques, nous avons exploré les rôles biologiques d’une signalisation de type aldéhyde dans les interactions kelp/herbivores. Nous avons montré que les aldéhydes pouvaient modifier le métabolisme d’une algue par l’activation du métabolisme des acides gras, et que l’application de 4-HHE sur L. digitata pouvait réduire significativement une consommation algale ultérieure par les herbivores. Ainsi, ces résultats participent à une meilleure compréhension des réponses de défense suite à un broutage chez les laminaires, et confortent l’existence d’une signalisation à distance dans les interactions avec les herbivores, qui impliquerait des composés de défense émis par les algues, dont les aldéhydes. / Kelps are founding species of temperate marine ecosystems, they evolve in the intertidal coastal areas where they are often challenged by herbivores. As most of sessile organisms, kelps develop defensive strategies against herbivory. In the kelp Laminaria digitata, elicitation by oligoguluronates induced regulations of transcription and metabolic pathways, leading to production and release of metabolites, such as aldehydes, in the environment. Moreover, this kelp species feature systemic responses upon defense elicitation and waterborne compounds surrounding a kelp bed have shown to modify its defense physiology. Such distant chemical signaling during defense responses are reminiscent of systemy and priming mechanisms in plants. In marine kelp beds, it should have a major ecological role in structuring marine algal and herbivore communities. In the context of kelp/herbivore interactions, we investigated the defense responses and signaling processes in two emblematic kelp species from north Atlantic and South Pacific coasts, involved in specialized interactions with their herbivores, L. digitata in interaction with Patella pellucida (Brittany, France) and Lessonia spicata with Scurria scurra (Chile). Combined approaches of metabolomics and bio-assays were carried out to decipher the nature of the putative chemical cues, and their biological and ecological roles in algal defense against herbivores. Results showed that, in response to grazing, kelps featured metabolic modifications such as induction of fatty acids, oxylipins and amino acids biosynthetic pathways, as well as transcriptomic modifications. Moreover, we observed that kelps co-incubated with grazed algae exhibited endo-metabolome changes compared to grazed one, and seemed to be less consumed during a subsequent grazing, suggesting the perception and integration of herbivory-induced algal compounds in neighboring algae. As field and lab studies previously highlighted a strong release of aldehydes into the air and the seawater following biotic and abiotic stresses, we further explored the biological roles of aldehyde-based signaling in kelp/herbivore interactions. We found that aldehydes could modify algal metabolism, including the activation of fatty acid metabolism, and that the application of 4-HHE on L. digitata could significantly reduce later algal consumption by herbivores. Thus, these results contribute to a better understanding of defense responses following grazing in kelps, and revealed the occurrence of distance signaling during interaction with herbivores, which could involve algal emitted compounds, such as aldehydes.

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