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Graham, Michael Hall. "Planktonic patterns and processes in the giant kelp Macrocystis pyrifera /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p9993988.
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Rautio, Caroline. "Kelp : Vertikal odling för inomhusmiljö." Thesis, Mittuniversitetet, Institutionen för design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-36642.
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Vertikal odling är en växande trend och det är trevligt att ha växter hemma, det ger en känsla av hemtrevnad. Växter bidrar till bättre luftkvalité eftersom de genom fotosyntesen suger i gifter som finns i våran inomhusluft och samtidigt producerar de syre. Växter önskar vatten och ljus för att överleva och för att fotosyntesen ska fungera. Som designer vill jag ge vertikal odling funktion och formkvalité. Det ska inte bara vara praktiskt utan estetiskt tilltalande. Ett smycke att sätta på väggen.
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Hobday, Alistair James. "Faunal patterns and dispersal on kelp rafts in Southern California /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035917.
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Campbell, Iona. "The potential influence of kelp exudates produced at large-scale kelp cultivation sites on microplankton assemblages." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230135.
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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.
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Liptack, Michael Keith. "Contributions to the molecular biology of kelp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ51890.pdf.
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Boizard, Sophie Marie Dominique Sandrine Valerie. "The ecology and anchorage mechanics of kelp holdfasts." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31258.
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The intertidal zone on wave-swept shores is among the most stressful environments on earth. The ability of organisms to survive and thrive in such environments depends on their ability to withstand breakage and wave dislodgement. The research presented in this thesis investigated two aspects of the biology of kelp holdfasts. I first examined whether the recruitment of the kelp Hedophyllum sessile was facilitated by the presence of holdfasts of adult conspecifics and how canopy cover and wave-exposure mediated this interaction. Field experiments indicated that adult holdfasts and substrata of high structural complexity, such as articulated coralline algae, enhanced recruitment. However, the ability of structurally complex substrata to facilitate recruitment depends largely on the extent of canopy cover and to a lesser extent on wave-exposure. Mechanisms by which canopy cover mediates substratum-specific recruitment processes may hold significant implications for population persistence and successful recruitment, especially following periods of high disturbance. Secondly, I investigated the functional morphology of the holdfast of the kelp Laminaria setchellii in relation to its role in providing attachment to the substratum and resistance against wave dislodgment. Results of field investigations indicated that the thallus of L. setchellii responds to increased wave exposure by decreasing blade size and increasing holdfast size; a concomitant increase in holdfast attachment force was not observed. At high wave exposure sites, the integrity and attachment of L. setchellii holdfasts is jeopardized by the presence of barnacles and burrowing crabs. Field investigations further showed that L. setchellii exhibits asymmetry with respect to the prevailing wave direction. The blade and upper part of the stipe are oriented with their longer axis perpendicular to the flow so that reconfiguration and bending is facilitated. The lower part of the stipe and holdfast are oriented with their longer axis parallel to the flow, resisting bending. By exhibiting such pattern of asymmetry along it thallus, L. setchellii avoid large hydrodynamic forces while still avoiding large swaying and remaining off the substratum in water of higher light intensities and velocities.Science, Faculty of
Botany, Department of
Graduate
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Fraser, Ceridwen, and n/a. "Phylogeography of the kelp genus Durvillaea (Phaeophyceae: Fucales)." University of Otago. Department of Zoology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20091002.131226.
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Durvillaea, a kelp genus occurring only in the Southern Hemisphere, presents an ideal system for studies of marine connectivity and postglacial recolonisation. Durvillaea contains five currently-recognised species, four of which are non-buoyant. Whereas all non-buoyant species are restricted to the south-western Pacific, the sole buoyant species (D. antarctica) has a far wider, circumpolar distribution, strongly suggesting that long-distance dispersal in D. antarctica is achieved by rafting. This contrast in predicted dispersal ability among Durvillaea species provides an opportunity for natural phylogeographic comparisons, thereby assessing the effectiveness of rafting as a long-distance dispersal mechanism. Additionally, the inability of D. antarctica to survive in ice-affected areas, combined with its broad distribution, make it an ideal candidate for studies of postglacial recolonisation.
Phylogenetic and biogeographic relationships within Durvillaea were here assessed using sequence data from mitochondrial (COI), chloroplast (rbcL) and nuclear (18S) DNA. Genetic data were obtained from more than 500 specimens, including representatives from across the geographic range of each recognised species of Durvillaea. Mitochondrial data for Durvillaea were found to be highly phylogenetically informative, with 117 variable sites observed over a 629 bp fragment of COI. Chloroplast and nuclear markers, on the other hand, showed less variation than COI, but nonetheless contributed useful phylogenetic information. Phylogenetic analyses were performed using both Maximum Likelihood and Bayesian approaches.
Contrasting patterns of genetic diversity were observed across the range of D. potatorum in Australia, with genetic homogeneity throughout western sites versus relatively high levels of diversity in eastern populations. Based on these results, I hypothesise that D. potatorum recolonised much of the western part of its range postglacially, perhaps being entirely eliminated from western Tasmania during the last glacial period by altered oceanographic systems. Additionally, 'western' and 'eastern' D. potatorum haplotypes formed deeply-divergent clades, likely reflecting geographic isolation on either side of the Bassian Isthmus during Pleistocene marine regressions.
Substantial genetic diversity was observed across the range of the circumpolar species D. antarctica. Within New Zealand, phylogenetic and morphological analyses of D. antarctica indicate that two morphotypes ('cape' and 'thonged' forms) likely represent reproductively isolated species, with the 'cape' lineage apparently restricted to southern New Zealand. Whereas the 'cape' lineage showed little genetic variation throughout its range, the 'thonged' lineage exhibited marked phylogeographic structure, with high genetic diversity and a clear north - south genetic disjunction delineated by the Canterbury Bight.
On a broader, circumpolar scale, D. antarctica showed contrasting patterns of genetic diversity, with high levels of variation in low-latitude regions (e.g., continental coasts of New Zealand and Chile), versus near-homogeneity at high, subantarctic latitudes. These phylogeographic contrasts strongly suggest that D. antarctica recolonised much of the subantarctic region only recently, most plausibly following extirpation by ice scour at the Last Glacial Maximum (LGM). Locations of putative recolonised islands relative to 'refugial' areas indicate that Antarctic sea ice was likely more extensive at the LGM than previous studies have suggested.
Latitudinal contrasts in genetic diversity were also observed among Chilean populations of D. antarctica, with a single mitochondrial haplotype detected throughout Chilean Patagonia versus high diversity in central Chile (32�-42�S). The Patagonian populations appear to have recolonised the region postglacially, following recession of the Patagonian Ice Sheet after the LGM. These populations show transoceanic ancestry, with a closer relationship to populations in the subantarctic and southern New Zealand regions than to those in central Chile. Substantial phylogeographic structure was evident across small spatial scales in central Chile, and the correspondence of major genetic disjunctions among central Chilean sites with the presence of long stretches of unsuitable substrate (beaches) strongly suggests that habitat discontinuity drives genetic isolation in this dispersive species.
Broad-scale molecular phylogenetic analyses indicate that the current taxonomy of Durvillaea species requires substantial revision. Previously-recognised 'morphotypes' of Durvillaea (of D. potatorum in Australia, and D. antarctica in New Zealand), for example, were here found to be genetically distinct, likely representing reproductively-isolated species.
This phylogeographic research on Durvillaea kelp sheds new light on the historical impacts of climate change on Southern Hemisphere marine environments, and on the processes driving evolution in a marine macroalga.
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Dyer, David Clifford. "Stable isotope ecology of South African kelp forests." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29601.
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Kelp forests are some of the most productive coastal ecosystems in the world and provide numerous ecosystem goods and services. Where they occur, they play a key role in coastal ecology and local fisheries. In South Africa, Ecklonia maxima and Laminaria pallida form kelp forests which support diverse ecological communities. The species composition of these communities has been shown to be spatially variable along the South African coast, controlled by abiotic processes and species interactions. Despite their importance in the southern Benguela Current Large Marine Ecosystem (BCLME), large-scale research directed towards these habitats has largely waned over the past 30–40 years, prompting a renewed focus on these systems. Stable Isotope Analysis (SIA) is an indispensable tool for investigating food web characteristics, with particular focus on trophic structure and functioning. SIA can be used to understand the basal isotope variability in producers, determine the primary carbon sources of food webs, and investigate the spatial and temporal patterns in consumer isotope values and trophic niches. Unlike in other global kelp ecosystems, this methodology has not yet been applied to the kelp forests in South Africa. A study among eight geographically separate sites and two seasons highlights the natural variability of stable isotope values (δ13C and δ15N), at different spatial and temporal scales, within the two dominant kelp species. Additionally, stable isotope variability was investigated within and among different tissues within both kelp species. Within a kelp plant, δ13C values had a range of 1.65‰ for E. maxima and 1.52‰ for L. pallida. The δ15N values had a range of 3.75‰ for E. maxima and 4.21‰ for L. pallida. There were also consistent variability patterns along the length of a single frond in both species, for both isotopes. Among the localities, E. maxima and L. pallida were highly variable with ranges in δ13C (9.37‰ and 11.22‰) and δ15N (3.44‰ and 4.51‰) for the two species respectively. The δ13C values of L. pallida and E. maxima displayed a clear pattern coinciding with depth, particularly for L. pallida. Within-site variability was a major contributor to the overall spatial variability for both species. This provides further evidence for the importance of understanding basal variability of stable isotope values when determining the carbon sources of bottom-up controlled ecosystems. Variability in particulate organic matter (POM) composition is hypothesized to be related to upwelling processes in, and around, a typical west coast kelp forest. Various variables were used to characterise the composition, and determine the dynamics, of the POM along two transects (alongshore and off-shore) originating within a kelp forest. SIA was employed to estimate the contribution of kelp-derived detritus (KDD) to the POM present in the water column, using a unique approach for isolating phytoplankton and kelp end-member values. Under upwelling conditions, stable isotope analyses confirmed the dominance (>70%) of kelp detritus in POM samples, even at distances of 7.5 km off-shore. Under downwelling conditions, however, phytoplankton was dominant (>60%) along both transects. This study therefore highlights the importance of coastal processes such as upwelling for controlling the composition of POM in kelp forests, as well as illustrating how the natural variability in POM composition created by upwelling processes can be used to gather POM endmember isotope values. Three ecologically distinct kelp forest communities were investigated using a combination of SIA and community-wide niche metrics ('Layman metrics’ and Bayesian inferences). Three kelp forests, with differing community composition were selected, including a west coast kelp forest, a False Bay kelp forest and a lobster-invaded kelp forest located east of Cape Hangklip at Betty’s Bay. Temporal and spatial variability in stable isotope values was identified in producer and consumer stable isotope values, but was variable among species. Community-wide metrics showed clear seasonal patterns, but despite large differences in community structure, metrics were not vastly different among sites. Seasonal variability was the largest observable trend in metrics at all sites. Community niche areas showed a high degree of overlap (80–95%) further illustrating the similarity among sites and seasons. These findings are largely contrary to expected patterns from community composition data. Trophic position and isotope niche of the West Coast Rock Lobster (Jasus lalandii) was determined at three ecologically different kelp forest habitats, located in Marine Protected Areas in south-western South Africa. Temporal and spatial variability in trophic position and niche size were detected. The stable isotope niche and trophic position of lobsters at Betty’s Bay were markedly different from those at Oudekraal and Bordjiesrif, with the summer niche being distinct (0% overlap). Trophic position was lowest at the lobster-invaded Betty’s Bay (2.52) and highest at Bordjiesrif (3.16). Similarly, the isotope niche of Jasus lalandii was significantly constricted at Betty’s Bay compared to the other two study sites. Primarily, these results show that in the region where these lobsters have invaded, the trophic niche is considerably constricted. This likely to be a consequence of the higher densities of lobsters in this area. These findings highlight the influence of the lobster invasion on Jasus lalandii itself, adding to the already published ecological effects on the kelp forest ecosystem as a whole. These findings also highlight the differences in trophic niche of this species, despite the overall community niche showing little difference among sites. The findings of this thesis provide estimates of the variability in stable isotope values of kelp forest seaweeds and consumers, as well as addressing the importance of ocean processes such as upwelling in controlling POM composition in kelp forests. Additionally, the trophic niche of a key kelp forest predator was characterised in ecologically different kelp forests, providing evidence of the effect of community structure on the niche of this species. This is the first concerted research effort into the stable isotope ecology of South African kelp forests, providing an updated look at the ecology of these important ecosystems, and serves as a foundation for future studies of this type.
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Kennelly, Steven James. "The Empirical Study of Marine Biological Resources." University of Sydney, Marine Studies Centre, 1999. http://hdl.handle.net/2123/390.
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The papers presented in this thesis represent my contributions to the empirical study of marine biological resources. This research has adopted the same experimental approach to: (i) develop scientifically validated techniques to solve specific problems; (ii) use these techniques to detect patterns and form conceptual models about the processes that may have caused them; (iii) do manipulative field experiments to support or refute hypotheses derived from these models; (iv) use these results to develop new models and hypotheses and to test them in new experiments; and (v) recommend, where appropriate, changes to the management of the resources examined. A rigorous, empirical approach is the common feature throughout my research (in its overall direction and subject-to-subject execution) and represents one of the few attempts to adopt such an approach across the three fields in which I have worked: (1) the ecology of underwater kelp systems; (2) the biology of and fishery for a commercially exploited crab; and (3) solving by-catch problems in commercial trawl fisheries.
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Hoos, Jennifer Piper Jorve. "Climate change impacts on the kelp life history cycle." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52166.
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Anthropogenic climate change will cause changes to the abundance, distribution, and survival of species in ecosystems worldwide. Kelps are foundation species that form the structure of temperate, marine ecosystems on coastlines worldwide. Kelps support highly productive communities that are ecologically and economically valuable, but are susceptible to the increases in environmental stressors associated with climate change. This susceptibility varies with life history stage, with macroscopic stages less sensitive to environmental stress than microscopic stages. I addressed the effects of climate change on the different life history stages of intertidal kelp from rocky shores on the Pacific coast of North America. I began with two studies on the interactive effects of multiple climate stressors on microscopic stages of kelp. Increasing temperature, CO₂, and UV caused mechanical and functional damage to zoospores during their motile phase, and caused further reductions in settlement, germination, and adhesion of the initial sessile phase of the life history cycle. Settlement style was also affected, with decreased time spent looking for suitable attachment locations and microenvironments, and overdispersion of spore settlement distribution, which has been shown to decrease fertilization rates and sporophyte abundance.
In my final research chapter, I describe the effects of increases in frequency of extreme warming events on macroscopic juvenile and adult kelp sporophytes. I also manipulated adult density in situ to determine the stress ameliorating affect of neighbor proximity on both juvenile recruitment and seasonal adult growth along a vertical tidal gradient. Extreme warming treatments reduced recruitment and seasonal growth of adults in the upper shore when adult density was low and environmental stressors were not mitigated by neighboring individuals. All other treatment combinations showed slightly positive effects of warming on recruitment and adult size. I predict that the aforementioned population effects resulting from increases in frequency of extreme warming events will cause an overall reduction in this species’ habitable vertical space in the intertidal zone. The combined impacts of overall reductions in microscopic life history stages with decreasing recruitment and habitable space for the macroscopic life history stage indicate overall reductions in abundance of future populations of intertidal kelp species.Science, Faculty of
Zoology, Department of
Graduate
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Lightfoot, Dennis G. (Dennis George). "Combined fields (electro-osmosis and pressure) dewatering of kelp." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68202.
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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.
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Liggan, Lauran. "Under pressure : biomechanics of buoyancy in Bull Kelp (Nereocystis leutkeana)." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57857.
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Maintaining buoyancy with pneumatocysts is essential for subtidal seaweeds with long flexible thalli, such as Nereocystis luetkeana (Nereocystis), to achieve an upright stature and compete for light. However, as Nereocystis grows, pneumatocysts are exposed to significant changes in hydrostatic pressure. Exposure to changing hydrostatic pressure could cause complications since the pneumatocyst is filled with gases that may expand or contract, potentially causing pneumatocysts to break, flood, and no longer be buoyant. This study explored how Nereocystis pneumatocysts resist biomechanical stress and keep the developing sporophyte upright in the water. Throughout development, pneumatocysts had an internal pressure consistently less than atmospheric pressure (3 – 100 kPa), indicating pneumatocysts always experience compressional loads. The structural integrity and design of the pneumatocyst to resist buckling was assessed by measuring compressional modulus (material stiffness), calculating material stress, analyzing critical geometry, and estimating critical buckling pressure. Small pneumatocysts found at depth (inner radius = 0.8 - 0.9 cm; wall thickness = 0.2 cm) were demonstrated to have reached a critical size in development and are at greatest risk of buckling. Pneumatocysts do not adjust material properties or geometry to reduce wall stress, but they are naturally resistant to hydrostatic loads. Critically small pneumatocysts are estimated to buckle at 35 m depth, which was observed to be sporophytes’ lower limit in the field. Data suggest that hydrostatic pressure, not just light limitation, might explain the maximum depth to which Nereocystis is capable of growing. Pneumatocyst gas composition did not change throughout development, and contrary to previous studies, internal gas concentrations were different from the atmosphere with O₂, N₂, CO, and CO₂ concentrations of 59%, 40%, 1.6%, and 0.6% respectively. Furthermore, pneumatocyst surface area to volume ratio did not correlate with the exchange of gases produced from photosynthesis and respiration. As sporophytes grow, total buoyant force is steadily outpaced by the weight of growing thalli, and the risk of the pneumatocyst sinking increases. Adult sporophytes are estimated to sink when pneumatocysts volume reaches 1.3 L, close to the maximum observed size in the field.Science, Faculty of
Botany, Department of
Graduate
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Balch, Toby. "Settlement and recruitment of echinoderms in kelp beds and barrens." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0018/NQ57358.pdf.
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Bernard, Miriam. "Molecular interactions between the kelp saccharina latissima and algal endophytes." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS105.
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Des algues brunes endophytes envahissent les tissus des laminariales, avec des effets potentiellement négatifs sur leur hôte. Des études moléculaires ont permis d'identifier deux genres, Laminarionema et Laminariocolax, dominant la diversité de ces endophytes. Une étude épidémiologique par qPCR a montré une forte prévalence de l'endophyte Laminarionema elsbetiae chez Saccharina latissima, avec des variations saisonnières et locales. En laboratoire, la présence de L. elsbetiae induit des réponses physiologiques différentes chez S. latissima, son hôte principal, et chez Laminaria digitata, un hôte occasionnel. Une approche transcriptomique a révélé des réponses moléculaires différentes chez les deux hôtes et l'endophyte, en lien avec les mécanismes de reconnaissance et de défense des deux partenaires. Ces spécificités du dialogue moléculaire lors des premières étapes de l'interaction pourraient expliquer la variabilité des profils d'infection observés dans les populations naturellesEndophytic brown algae invade stipes and fronds of kelps with potential negative effects for their hosts. The molecular diversity of kelp endophytes was investigated and a majority of the isolated endophytes belonged to the genera Laminarionema and Laminariocolax. Using a qPCR approach, a high prevalence of the endophyte Laminarionema elsbetiae was detected in natural Saccharina latissima populations, but with seasonal and geographical variations. Co-cultivation experiments showed different physiological responses of the main host, S. latissima, and an occasional host, Laminaria digitata, to L. elsbetiae. A transcriptomic approach revealed important differences between the molecular responses of the two kelps, related to the recognition of the endophyte and subsequent defence reactions. These specific differences in the molecular cross-talk during the early steps of the interaction could explain the variability of natural infection patterns in kelp species
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de, Bettignies Thibaut. "Sources and supply of kelp detritus : quantifying mechanisms of production." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/564.
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In temperate waters, rocky reefs dominated by extremely productive kelp beds export considerable primary production. Despite the extensive body of work on kelp detritus as a trophic subsidy, many questions remain about the production of this detritus. The aim of this thesis was to determine the rate and mechanisms of kelp detritus production, for Ecklonia radiata, the dominant kelp species in temperate Australia. Most of the work was conducted in Marmion Lagoon located 20 km North of Perth, south-western Western Australia, a region strongly influenced by oceanic swell and winter storms. The study comprised of four major components: the impact of kelp morphology on the drag forces acting on kelp thalli; investigation of wound patterns in kelp tissue and the biomechanical implications for kelp detritus production; the relative contribution of erosion of frond material and dislodgement of whole thalli to detritus production; and the relationship between kelp dislodgement and peak water velocities, implemented with a kelp dislodgement model.
The initial work in chapter 1 revealed that only size (total area), not morphology, was important in determining the drag acting on E. radiata at peak velocities. This implied that at storm velocities the only way drag forces acting on a kelp can be reduced is by a reduction of total thallus area (biomass) and not by modification of thallus shape. These results constituted the first step to build a mechanistic model of kelp dislodgement.
In chapter 2, it is shown that wounds were highly abundant on kelps before peaks in winter storms and that simulated wounds caused significant loss of tissue integrity and strength. Collectively, these findings suggest that accumulation of wounds over summer results in kelp pruning (tissue fragmentation) in early winter. Paradoxically, this may increase kelp survival during winter storms because the biomechanical drag is much lower on small, pruned kelps (lower biomass).
Results presented in chapter 3 indicated that erosion accounted for 80% of the annual detrital production with a pulse in autumn, whereas dislodgement accounted for a smaller and more constant proportion throughout the year. Neither erosion nor dislodgement correlated with increasing water velocity. Instead, the pulse of detrital 4 production coincided with sporogenesis, leading to the hypothesis that weakening of structural tissue through the formation and release of spores made E. radiata more susceptible to wound accumulation (Ch. 2) and erosion.
In chapter 4, results are presented that show no increase in kelp dislodgement with increasing water velocity, except during the most severe storms. The dislodgement model indicated that the seasonal variation in individual kelp biomass, resulting from erosion of frond tissue (Ch. 3), resulted in lower susceptibility to dislodgement (lower biomass) at times of peak water velocities. The benefit of erosion in reducing drag acting on the thallus, as proposed in the previous chapters, was therefore demonstrated by the model.
The commonly accepted model of wave-driven mortality of kelp during storms in winter was refined by the results. The experimental, field sampling and modelling studies have been synthesised into an alternative model of kelp dislodgement, in which kelp beds are in dynamic equilibrium with wave disturbance. This equilibrium is mediated through erosion-driven adjustment of individual kelp biomass in autumnwinter which lowers drag on kelp thalli during the period of peak water velocity. This relationship between erosion and the susceptibility of E. radiata to dislodgement suggests an adaptation of the kelp E. radiata to its environment, critical to kelp survival in one of the most hydrodynamically challenging environment.
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Drummond, Hazel. "Distribution and biomass of epiphytic seaweeds on the kelp Ecklonia maxima (Osbeck) Papenfuss, and the potential effects of two kelp-harvesting methods in the Western Cape." Bachelor's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/25563.
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The demand for freshly harvested kelp, Ecklonia maxima, in the Western Cape, has greatly increased due to the need for fodder to supply the growing abalone industry. There is evidence suggesting that the present demand may exceed the amount of E. maxima available, if the traditional method of harvesting continues (cutting the whole kelp plant off, just above the holdfast). There is also evidence that, although the kelp beds recover in 2 - 3 years, and are ready for the next harvesting event, the epiphytic seaweed populations have not recovered even 5 years after harvesting. A new method of harvesting has been proposed, where the secondary blades of the E. maxima are cut 30cm from the primary blade. This method would increase the amount of kelp that can be harvested sustainably. This study investigated whether this new method of harvesting would have less impact on the epiphytic seaweed populations, particularly the three obligate epiphyte species; Carpoblepharis flaccida, Polysiphonia virgata and Suhria vittata, and whether there is pattern of distribution of epiphyte populations around the Cape Peninsula. The distribution of the epiphytes on the different portions (stipe; primary blade and first 30cm of secondary blades; rest of the secondary blades) of kelp was investigated. E.maxima was sampled at five sites around the Cape Peninsula, and the epiphytes on each portion were identified and weighed. All the epiphytes except Carpoblepharis flaccida were found predominantly on the portion of kelp that would be left after the new method of harvesting, and would therefore be unaffected. It was found that the mass of C.flaccida removed in the new method was not significantly different from the mass remaining; therefore a large proportion is left untouched. There was no geographic pattern of distribution of C.flaccida in relation to water temperature around the Cape Peninsula. The results suggest that this new method of harvesting would have little impact on the epiphyte populations, which is an added incentive for changing the method of harvesting.
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Orr, Kyla Kathleen. "Predicting the ecosystem effects of harvesting beach-cast kelp for biofuel." Thesis, University of the Highlands and Islands, 2013. https://pure.uhi.ac.uk/portal/en/studentthesis/predicting-the-ecosystem-effects-of-harvesting-beachcast-kelp-for-biofuel(82d8913a-164a-4e21-b61b-9f83b462b079).html.
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Beach‐cast kelp (principally Laminaria spp.), known as macroalgal wrack, has been suggested as a feedstock for biofuel. However, to be extracted sustainably it is necessary to understand its ecological role and predict the impacts of its removal. Field‐based observations combined with food web modelling were used to predict the ecosystem effects of removing wrack from beaches of the Uists, western Scotland. Beaches with wrack were associated with enriched benthic infauna (polychaetes) on the lower shore, and wrack mounds supported abundant macroinvertebrates (mainly Diptera larvae and oligochaetes); with some of the highest biomasses reported globally for beaches. These fauna are valuable prey to shorebirds, as demonstrated by a strong positive relationship (R2 = 0.82) between wader abundances and the percentage cover of wrack on beaches. Inshore, drifting macroalgae was associated with elevated abundances of detritivorous hyperbenthic fauna (mysids, isopods and gammarid amphipods). In addition, the volume of drifting macroalgae inshore was a significant predictor (along with physical beach characteristics) for the abundance of decapods and fish. Food web models and network analysis indicated that beaches which accumulate wrack had a greater diversity of trophic links and more functional redundancy, making their food webs more resilient to perturbations. Such perturbations may include stressors induced by climate change, such as increased erosion of sediments during storms, elevated atmospheric and sea surface temperatures and elevated CO2 concentrations. Model simulations of wrack harvesting predicted an immediate decline in primary consumers in direct proportion to the quantity of wrack removed, and a slow decline in shorebirds in response to reduced prey. Primary consumers were predicted to recover to their pre‐harvest biomasses within 1 to 2 years regardless of harvesting intensity, but recovery times for shorebirds were an order of magnitude longer, and increased with harvesting intensity. Harvesting more than 50% wrack predicted a ‘collapse’ in wader populations within 25 years, and recovery times of 45‐60 years were estimated if >70% wrack was removed. The findings of this thesis suggest wrack provides essential food and shelter to coastal fauna, and its large‐scale removal would have significant negative impacts to the ecosystem functioning.
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Swanson, Andrew K. "Ecophysiological adaptations of northeast Pacific kelp communities to ultraviolet light stress." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0022/NQ51923.pdf.
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Williamson, Benjamin. "Developing a holonomic iROV as a tool for kelp bed mapping." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600219.
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Kelp beds support a vast and diverse ecosystem including marine mammals, fish, invertebrates, other algae and epibiota, yet these kelp beds can be highly ephemeral. Mapping the density and distribution of kelp beds, and assessing change over yearly cycles, are important objectives for coastal oceanography. However, nearshore habitat mapping is challenging, affected by dynamic currents, tides, shallow depths, frequent non-uniform obstacles and often turbid water. Noisy and often incomplete sensor data compound a lack of landmarks available for navigation. The intelligent, position-aware holonomic ROV (iROV) SeaBiscuit was designed specifically for this nearshore habitat mapping application and represents a novel synthesis of techniques and innovative solutions to nearshore habitat mapping. The concept of an iROV combines the benefits of autonomous underwater navigation and mapping while maintaining the flexibility and security of remote high-level control and supervision required for operation in hostile, complex underwater environments. An onboard battery provides an energy buffer for high-powered thrust and security of energy supply. Onboard low-level autonomy provides robust autopilot features, including station-keeping or course-holding in a flow, allowing the operator to direct the survey and supervise mapping data in realtime during acquisition. With the aim of providing high-usability maps on a budget feasible for small-scale field research groups, SeaBiscuit fuses the data from an orthogonal arrangement of a forward-facing multibeam sonar and a complementary 360° scanning sonar with a full navigation suite to explore and map the nearshore environment. Sensor fusion, coupled with the holonomic propulsion system, also allows optimal use of the information available from the limited budget sensor suite. Robust and reliable localisation is achieved even with noisy and incomplete sensor data using a relatively basic Inertial Navigation System and sonar-aided SLAM in the absence of an expensive Doppler velocity log or baseline navigation system. Holonomic motion in the horizontal plane and an axisymmetric hull provide the manoeuvrability required to operate in this complex environment, while allowing 3D maps to be generated in-transit. The navigation algorithms were tested mapping a piling dock and the habitat mapping sensors calibrated using an ‘artificial’ kelp bed of manually dimensioned kelp stipes transplanted to a sheltered but open-water real-world environment. Sea trials demonstrated mapping open ocean kelp beds, identifying clusters of stipes, converting this into a useful measure of biomass and generating a density surface across the kelp bed. This research provides field-proven techniques to improve the nearshore habitat mapping capabilities of underwater vehicles. Future work includes the transition to full-scale kelp bed mapping, and further development of the vehicle and sensor fusion algorithms to improve nearshore navigation.
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Kelp, Romed [Verfasser]. "Strategische Entscheidungen der europäischen LKW-Hersteller im internationalen Wettbewerb / Romed Kelp." München : VVF, 2000. http://d-nb.info/995598835/34.
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West, Adam. "Substrate dependant survivorship of Ecklonia maxima, in southern African kelp communities." Bachelor's thesis, University of Cape Town, 1996. http://hdl.handle.net/11427/25867.
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Several south-western Cape Ecklonia maxima communities were examined to determine their basic demography and the effects of substrate selection. Overall percentage substrate composition, stipe lengths and substrate attachment for all kelps were recorded at four sites off the Cape Peninsula. Strength of attachment to different substrates was measured. Selection for substrate type was analysed using Jacobs' index. A substrate of Pyura stolonifera was the most common for juveniles, whereas substrates of rock and conspecific holdfasts were dominant in the larger individuals. No significant difference in strength of attachment was found for kelps less than 50 cm. An analysis of the frequency of single- and multi-stiped holdfasts indicates that survival on rock is greater than on that of holdfasts. Size-class distributions indicate that E. maxima is a shade-tolerant species showing advanced regeneration. Establishment on rock may occur through episodic recruitment escaping grazing pressure. In areas with low grazing intensity, recovery from catastrophic storms may be limited by competition with understorey algae.
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Dunga, Victor Loyiso. "Mapping and assessing ecosystem threat status of South African kelp forests." Master's thesis, Faculty of Science, 2020. http://hdl.handle.net/11427/32241.
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At a global scale, kelp forests play a significant ecological, social and economic role through their provision of ecosystem services. South African kelp forests are no exception and recent studies have established their value. To maintain these benefits, informed management is needed. An understanding of kelp forest distribution, ecosystem functioning, pressures, and ecosystem state are key requirements for effective management. The South African National Biodiversity Assessment (NBA) synthesises research to report on the status of ecosystems to guide policy, planning and decision making. Kelp forests were excluded from two previous national assessments, as they were not represented on the National Map of Marine Ecosystem types. This thesis aimed to address this omission by producing a map of kelp forest ecosystem types and conducting the first assessment of their threat status. This study sought to develop a modern method for mapping South African kelp forests to update previous maps developed in the mid-2000s. The novel approach extracts the Vegetation Index from kelp forests using advanced multi-resolution Sentinel-2 (A and B) satellite imagery. Using Geographic Information Systems, spectral bands 4 (RED) and 8 (NIR) (10 m resolution) were utilized to calculate Normalised Difference Vegetation Index (NDVI). An expert-guided trial and error approach was adopted to set the NDVI threshold (-0.2) at a level suitable for detecting both subtidal and surface buoyant kelp to the limits of the Sentinel-2 platform. The results showed that the high resolution and deeper water column penetration of this platform enabled the filling of previous gaps and detect both subtidal and surface protruding kelps at low cost. Additionally, the map includes for the first time, the kelp recently reported to have shifted eastwards along the south coast. A total of 1300 km of kelp forest was mapped and three biogeographical subtypes distinguished. Combining the NDVI threshold method and Supervised Classification yielded satisfactory results and an accuracy of 76%. Sentinel-2 imagery was validated using observational classification from Google Earth, field surveys expert knowledge and previous maps. However, the Sentinel's depth penetration was affected by environmental heterogeneity along this coast. Results confirmed the complexities of retrieving spectral indices from environments with varying turbidity, depths, wave climates and the challenges associated with ground-truthing the expansive marine environment. This study advises comprehensive ground-truthing for the three kelp forest ecosystem types as a fundamental step towards long-term monitoring of South African kelp forests. The method developed advanced application of the NDVI in submerged aquatic vegetation mapping and could be modified to support mapping of other ecosystem types such as seagrasses, other seaweed habitats and inland aquatic vegetation. South Africa's new kelp forest map was then used to facilitate the first ecosystem threat status assessment for South African kelp forests using three criteria from the emerging International Union for Conservation of Nature Red List of Ecosystems (IUCN RLE). To assess threat status, ecosystem extent and condition were considered. Three kelp forest ecosystem types were assessed; namely Namaqua, Cape and Agulhas Kelp Forests and an additional combined single South African Kelp Forest to explore the effect of scale in assessing threat status. Literature was reviewed to develop a conceptual model to support the assessment and define ecosystem collapse. Thirteen relevant pressures were mapped to determine ecosystem degradation across the extent of each kelp forest type using a cumulative pressure mapping approach. Four categories of ecosystem condition were recognized in alignment with the IUCN thresholds for ecosystem degradation. The results of the ecosystem threat status assessment show sensitivity to the different assessment criteria, the scale of ecosystem delineation and assessment approaches. There is no reported reduction in the distribution for any of the South African kelp forest ecosystem types, therefore, the decline in extent under criterion (A) was assessed as Least Concern for all types. For criterion (B) which is related to geographic extent and threat, results were most sensitive to ecosystem delineation with results ranging between Least Concern and Critically Endangered under different sub-criteria and for different ecosystem types. Also, for the criterion (C) which is related to the extent of abiotic degradation, the results ranged from Vulnerable to Endangered under different sub-criteria and for different ecosystem types. Further work is needed to validate kelp forest ecosystem types; consider the implications of multiple scales of classification, mapping and assessment; improve pressure data, groundtruth ecosystem condition, and assess the disruption of biotic processes. In line with the protocols of the IUCN RLE, South African kelp forest ecosystem types appear threatened with plausible results ranging between Vulnerable and Endangered. The accuracy of these assessments can be strengthened by more research to refine conceptual models, calibrate assessments of degradation and better define thresholds of collapsed ecosystems.
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Rowbotham, Jack Steven. "Metal-uronide interactions and their relevance to the thermolysis of kelp." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/12084/.
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This thesis describes investigations into the coordination- and thermo-chemistry of metal-uronide complexes (namely alginates). The work probes the importance of such metal-saccharide interactions in the thermolysis of kelp, with a view to deriving valuable fuels and chemicals from this aquatic bioresource. In this regard, Chapter 1 justifies the model-compound approach adopted in this thesis, and outlines the wider context in which the work is set. Chapter 2 describes the isolation of the composite monosaccharides of alginate (D-mannuronate and L-guluronate) and their characterisation by NMR spectroscopy. A combination of 1- and 2-D 1H and 13C experiments were utilised to provide the most comprehensive assignments of algal mono-uronates to-date. Subsequently, the well-defined mono-uronate spectra were used to probe the conditions that favour hydrothermal uronolactone formation. Chapter 3 probed the response of the algal mono-saccharides (prepared and characterised in Chapter 2) to a range of metal ions (Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Zn2+, and Cu2+) to explore the validity of the well-known “Egg-box model” of metal ion/alginate coordination. By observing changes to anomeric equilibria, α-L-gulopyranuronate was found to coordinate (via an axial-equatorial-axial arrangement of hydroxyl groups) to large, divalent cations, in a manner consistent with “Egg-box binding”. In contrast, in the presence of Na+, Mg2+, Zn2+, and, Cu2+ α-L-gulopyranuronate interacted via its carboxylate moiety (and possibly ring oxygen), demonstrating the unsuitability of these ions for Egg-box binding. Chapter 4 describes the impact of the metal ions discussed in Chapter 3 on the subsequent pyrolysis behaviour of alginates (and related mono- and poly-uronides). Thermogravimetric analysis (TGA), pyrolysis-gas chromatography mass spectrometry (Py-GCMS), and solid-state studies of the post-thermolysis chars were all conducted. The uronides were generally found to demonstrate unfavourable thermal behaviour (high yields of char, CO2, and H2O, and low yields of condensable hydrocarbons). Complexation of Cu2+, however, had a beneficial impact on subsequent thermolysis, by increasing the low-temperature, selective formation of 2-furfural. The presence of Cu0 in the alginate char is indicative of Cu(II)-mediated alginate decomposition occurring via a Hofer-Moest type decarboxylation. Chapter 5 tested the validity of the model compound approach by enriching samples of kelp with either Cu2+ or Ca2+ ions and studying the thermal degradation of the resulting materials by TGA and Py-GCMS. The thermochemical outcomes for the whole biomass mirrored those found for the model compounds studied in Chapter 4. Finally, in Chapter 6, the results of Chapter 2 – 5 are analysed synoptically, and the success of the model compound approach is appraised. Ultimately, it is concluded that the ability of a metal ion to inhibit or promote thermal decarboxylation of a uronide (in isolation or within kelp) is more important in dictating pyrolysis behaviour than any differences in coordination to various hydroxyl groups around the saccharide ring. The results could find application in the development of a phytoremediative kelp-based thermal biorefinery.
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Van, Tussenbroek B. I. "Some aspects of the biology of the giant kelp, Macrocystis pyrifera, in the Falkland Islands." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233865.
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Leyton, Nain Carmen Cecilia. "Condiciones óptimas de fermentación de carbohidratos de algas pardas, mediante el uso de organismos genéticamente modificados." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/132151.
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Ingeniera Civil en BiotecnologíaEste informe presenta la memoria de título realizada en colaboración con el Consorcio BAL Chile S.A.; cuyo objetivo es evaluar las condiciones de fermentación de carbohidratos de macroalga parda para optimizar su bioconversión a etanol, mediante el uso de cepas de microorganismos genéticamente modificados, y así, contribuir al desarrollo de la industria de biocombustibles de tercera generación en Chile. El desarrollo de este proyecto consistió, principalmente, en dos etapas: en la primera se realizaron fermentaciones aeróbicas con reactivos puros en distintas razones de alginato-manitol, de modo de simular la composición de carbohidratos presentes en las macroalgas pardas. Con estos cultivos se calculó y evaluó la velocidad de crecimiento y los rendimientos de biomasa y de producto, con la finalidad de determinar condiciones óptimas para fermentar. En una segunda etapa, realizaron fermentaciones micro-aeróbicas mediante un diseño experimental estadístico, para evaluar, principalmente, la producción de etanol. No se obtuvieron resultados favorables en esta condición, por lo que procedió a fermentar Macrocystis pyrifera en condiciones aeróbicas, con el objeto de verificar si los resultados con reactivos puros era reproducible al fermentar algas. Como resultado principal se obtuvo que la razón de alginato-manitol que reporta mejor rendimiento de etanol es 5:8 en condiciones aeróbicas. No obstante, el microorganismo puede crecer y fermentar favorablemente en distintas razones de carbohidratos, lo que elimina la variable de composición química de algas pardas. Las fermentaciones con Macrocystis pyrifera determinaron que no es necesario que la razón de carbohidratos se asemeje a la razón óptima determinada como óptima, sino que basta con la composición natural de la misma. Por lo tanto, esta macroalga nativa de Chile y su uso como materia prima para la producción de biocombustibles abre una oportunidad importante para la aumentar la participación de las Energías Renovables No Convencionales en la generación de energía del país, avanzando hacia la meta propuesta por el gobierno. Tras los análisis realizados, se estima que el rol principal de manitol es entregar poder reductor a la célula, el cual puede ser utilizado tanto en el crecimiento y metabolismo del microorganismo, como para la producción de etanol. Por otro lado, alginato es consumido para la formación de biomasa y de piruvato destinado a la producción de etanol. El estudio experimental desarrollado en esta memoria no consideró variables como la temperatura, pH o agitación. Por lo tanto se recomienda complementar este estudio añadiendo dichas variables, otorgando otras perspectivas valiosas al momento de decidir el escalamiento del proceso.
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CHEMELLO, Silvia. "Brown macroalgae transplantation as habitat restoration technique: methods, effectiveness, and concerns." Doctoral thesis, Università degli Studi di Palermo, 2020. http://hdl.handle.net/10447/395281.
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Gómez, Murúa Javiera Del Pilar. "Biología sintética para mejorar la producción de Etanol en Escherichia coli BAL1611 a partir de carbohidratos de Macrocystis pyrifera." Tesis, Universidad de Chile, 2019. http://repositorio.uchile.cl/handle/2250/170222.
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Tesis par optar al grado de Magíster en Ciencias de la Ingeniería, Mención QuímicaMemoria para optar al título de Ingeniera Civil en Biotecnología
El aumento del consumo energético y la escasez de recursos de origen fósil, han impulsado proyectos de generación de biocombustibles de tercera y cuarta generación como el de producción de etanol a partir del alga chilena M. pyrifera mediante la bacteria E. coli BAL1611. En este estudio, se obtuvo rendimientos de producto y biomasa menores que los reportados con el alga original S. japonica. Hipotéticamente, habría un desbalance redox interno en la bacteria por lo que, para mejorar la producción de etanol, se decide estudiar in silico cómo afectan las fuentes de carbono en la distribución de flujos y concentración de metabolitos, y así proponer circuitos genéticos o metabólicos que regulen el sistema. Además, se decide proponer nuevos productos de interés comercial que se pueden generar desde M. pyrifera mediante E. coli BAL1611. Las simulaciones del modelo cinético construido para E. coli BAL1611 muestran que existe escasez de poder reductor intracelular, aunque la causa de la menor producción de etanol se debe a la saturación de la enzima KDG-6-fosfato aldolasa (EDA) de la ruta de Entner-Doudoroff. Los estudios para optimizar la producción de etanol a partir de M. pyrifera indican que la sobreexpresión de EDA y alcetaldehido deshidrogenasa (ALDH), junto con el knock-out de malato-quinona oxidorreductasa (MQO), es la combinación de mutaciones que genera el mayor rendimiento de producto/sustrato, correspondiente a 0,29, aproximadamente el doble que para el caso de la E. coli BAL1611 sin mutaciones. Por otra parte, analizando otros productos de interés como ácido láctico y succínico queda de manifiesto que, utilizando Macrocystis pyrifera como sustrato, E. coli BAL1611 es una inadecuada alternativa para generar ácido láctico debido a los bajos rendimientos alcanzados. En cuanto a ácido succínico, se propone como combinación de mutaciones la sobreexpresión de la enzima EDA y el transporte de succinato, junto con el knock-out de succinato deshidrogenasa (SDH) y ALDH, obteniendo un rendimiento de 2,37, cinco órdenes de magnitud mayor al caso de la E. coli BAL1611 original. Además, se observa una relación inversa entre el crecimiento y la producción para etanol y ácido succínico. Finalmente, se propone implementar las mutaciones respectivas para cada producto en un circuito genético que regule la producción mediante quorum sensing, disociando el crecimiento de la producción. Además, se sugiere realizar mejoras en el planteamiento de algunas ecuaciones del modelo, para luego construir una plataforma que permita determinar todos los bioproductos de interés comercial que puedan ser generados de forma eficaz a partir de Macrocystis pyrifera mediante la E. coli BAL1611.
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Ruotimaa, Jenny. "Are seals willing to pay for access to artificial kelp and live fish?" Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10340.
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Environmental enrichment (EE) is used to improve the wellbeing of animals in human care. One way of testing what resources an animal prefers to have access to, is to make it pay a price. The price is in the form of time or energy spent to get access to the resource. When measuring the motivation of animals it is useful to compare the resource which is to be evaluated to a resource with a known value. Food is often the comparator. The maximum price paid approach measures the highest price an animal is willing to pay for access to a
resource. In this study the motivation of a grey seal (Halichoerus grypus) for getting access to artificial kelp and live fish was measured. Food was used as the comparator. A large net cage with a weighted entrance and a nonweighted exit gate was used as the test arena. The seal had to enter it by opening the entrance gate which had increasing weights every day, in 10 steps up to 65 kg. The seal was not willing to pay any price for the live fish. The maximum price paid for the food was 60kg, and for the artificial kelp 10kg, i.e. 17% of the maximum price paid for food. The results suggest that neither
live fish nor artificial kelp was an attractive EE for this seal. However, the study also shows that spring (reproductive period) is not a good time to test motivation in grey seals.
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Gregr, Edward James. "Sea otters, kelp forests, and ecosystem services : modelling habitats, uncertainties, and trade-offs." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58818.
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Resource management is increasingly about the equitable distribution of benefits amongst a diversity of beneficiaries while ensuring the persistence of desirable social and ecological systems. Largely because of the complexity of social-ecological systems, models intended to support integrated resource management continue to suffer from poor treatment of uncertainty, and the challenges of defining appropriate model scope and benefit representation. I explored these challenges through the process of combining field data with population, habitat, and service models to build an integrated model of coastal ecosystem services on the West coast of Vancouver Island, British Columbia, Canada. I examined the tradeoffs between sea otter and invertebrate dominated systems under 3 spatial sea otter management plans. The model predicts that an otter-dominated system will produce, in aggregate, between 30 and 90 M$ / year more than one dominated by invertebrates. Disaggregation by benefits and by location provides insight into trade-offs and equity. For example, the value of increased finfish production from enhanced primary productivity is predicted to be almost double the losses incurred by the invertebrate fishery; while increased detail on the distribution of benefits supports the definition of novel, more equitable and legitimate indicators, allowing management alternatives to be more salient. Development of the model led to advances in the applied and theoretical aspects of integrated model development. Chapter 2 confirms that uncertainties and design assumptions are mostly ignored in the popular modelling literature, and includes a conceptual model to support more consistent model design decisions. In Chapter 3 I characterised key aspects of kelp ecology in Pacific Canadian waters, and showed how the trade-off between precision and accuracy depends on whether one is pursuing knowledge or application. Chapters 4 and 5 tell the story of the integrated model, respectively focusing on ecosystem service production, and the distribution of benefits. My results show how spatial resolution is key to identifying indicators of social and ecological value. All told, my dissertation offers applied, theoretical, and methodological advances in the use of ecosystem models for integrated management. Extending the model to include stakeholder objectives would complete the data-to-decision model, allowing formal decision analysis.Science, Faculty of
Resources, Environment and Sustainability (IRES), Institute for
Graduate
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Kusumo, Handojo Tjondro. "A parallel assessment of morphological and genetic diversity in the kelp Alaria marginata." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0015/NQ37724.pdf.
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Rosman, Johanna. "The effects of a kelp forest (Macrocystis pyrifera) on currents, waves and turbulence /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Teagle, Harry Andrew. "The influence of ocean warming on the provision of biogenic habitat by kelp species." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/427036/.
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Kelp forests represent some of the most productive and diverse habitats on Earth, and play a critical role in structuring nearshore temperate and subpolar environments. They have an important role in nutrient cycling, energy capture and transfer, and offer biogenic coastal defence. Kelps also provide extensive substrata for colonising organisms, ameliorate conditions for understorey assemblages, and generate three-dimensional habitat structure for a vast array of marine plants and animals, including a number of ecologically and commercially important species. This thesis aimed to describe the role of temperature on the functioning of kelp forests as biogenic habitat formers, predominantly via the substitution of cold water kelp species by warm water kelp species, or through the reduction in density of dominant habitat forming kelp due to predicted increases in seawater temperature. The work comprised three main components; (1) a broad scale study into the environmental drivers (including sea water temperature) of variability in holdfast assemblages of the dominant habitat forming kelp in the UK, Laminaria hyperborea, (2) a comparison of the warm water kelp Laminaria ochroleuca and the cold water kelp L. hyperborea as habitat forming species, and further investigation into the impacts of this subtle climate driven substitution of habitat forming kelps, and (3) experimental manipulation of densities of the dominant intertidal kelp in the UK, Laminaria digitata, in order to understand the impacts of climate driven loss of a dominant habitat forming species. L. hyperborea assemblages varied significantly between study regions spanning ~9° of latitude, as well as between and within sites at a local scale. Patterns in mobile and sessile assemblage structure were driven principally by different environmental factors. Overall patterns in the structure of biogenic habitat and assemblage structure did not vary predictably with latitude, indicating that other processes acting across multiple spatial scales are important drivers of assemblage structure. L. ochroleuca hosted impoverished assemblages associated with both holdfasts and stipes, compared with L. hyperborea. Further, climate driven increases in the relative abundance of L. ochroleuca relative to L. hyperborea lead to disruption of an important habitat cascade associated with the stipe of L. hyperborea and epiphytic algae. L. ochroleuca stipes typically lack the dense epiphytic assemblage associated with L. hyperborea, and host depauperate faunal assemblages which may have impacts on higher trophic levels. Experimental reduction in the density of L. digitata led to a dramatic shift in dominance from perennial to annual species, particularly the pseudo-kelp Saccorhiza polyschides on an exposed rocky shore. Impacts on a sheltered shore were subtler, and may have been tempered by the presence of another perennial kelp, Saccharina latissima. Loss of L. digitata led to a reduction in the standing stock of macroalgae after ~2.5 years of manipulation on both shores. These findings have significant implications for the structure and functioning of rocky shores in the future. Overall, anthropogenic climate change is likely to negatively impact the functioning of kelp forests as repositories of biodiversity in the future via the reshuffling of warm- and cold-water kelp species and through an overall loss of algal biomass and associated habitat due to continued increases in seawater temperature in the northeast Atlantic.
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Kelp, Alexandra [Verfasser]. "Generierung und Charakterisierung eines transgenen Rattenmodells der Spinozerebellären Ataxie Typ 17 (SCA17) / Alexandra Kelp." München : Verlag Dr. Hut, 2015. http://d-nb.info/1075409616/34.
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Coppin, Ross Mark. "Ecklonia maxima kelp forests along a thermal gradient: community composition and recovery from disturbance." University of the Western Cape, 2017. http://hdl.handle.net/11394/6163.
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Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol)Climate change will influence species distributions, survival and ecosystem functioning, mostly through changes in sea surface temperatures and storm disturbance. Species are expected to shift poleward in response to ocean warming, which will increase species interaction strength, and cause tropicalisation of temperate ecosystems. Furthermore, if storm frequency and magnitude increases, this could have detrimental effects for species already on their thermal limits. One such group of coastal species is kelp. Kelp are ecosystem engineers that rely on cool-temperate water for survival, and which support an array of fauna and flora. Kelp-based ecosystems are also highly productive, and provide important inorganic input into coastal food webs, largely through detritus. Temperature and disturbance have been shown to be important drivers of kelp ecosystems globally, and we expect that local changes in these drivers may affect kelp ecosystem composition and functioning along the south-western Cape coastline where they form extensive habitats.
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Rothman, Mark D. "Investigations into the harvesting ecology of the South African kelp Ecklonia maxima (Alariaceae, Laminariales)." Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/6177.
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Word processed copy.Includes bibliographical references.
This present study examines several questions that were not addressed by previous studies of South African Ecklonia maxima beds. Firstly, this thesis examined the distribution of kelp biomass, at various sites around the Cape Peninsula and on the west coast, and at different depths within sites. An attempt was made to calculate a single figure that could be used in determining the biomass of kelp beds.
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Pirker, John Georg. "Demography, Biomass Production and Effects of Harvesting Giant Kelp Macrocystis pyrifera (Linnaeus) in Southern New Zealand." Thesis, University of Canterbury. Zoology, 2002. http://hdl.handle.net/10092/1321.
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This study examined the demography of giant kelp Macrocystis pyrifera (Linnaeus) and its interactions with understorey algae and invertebrates in southern New Zealand over two and a half years. Most of the study was done at two sites within Akaroa Harbour (Banks Peninsula) but ancillary sites at Tory Channel (Marlborough Sounds) were used for parts of the study. The kelp forests within Akaroa Harbour were generally highly productive, with a high annual turnover of giant kelp. Macrocystis plants were mostly annual and rarely reached ages greater than 12 months. Peak recruitment occurred in spring (November) during 1995-97, but lesser recruitment episodes occurred throughout the year. The maximum growth rates of Macrocystis fronds were comparable to rates reported elsewhere in southern hemisphere populations (22 mm - 24.5 mmlday), but considerably lower than those in northern hemisphere populations. The major experiment incorporated in the study tested the effects of the Macrocystis canopy and the understorey canopy of the stipitate laminarian Ecklonia radiata on macroalgae and invertebrates. The experiment was structured so that the effects of clearances at different times could be determined. One impetus for this experiment was the need to address issues relating to the commercial harvesting of giant kelp, its sustainability and its effects on other species. The effects of canopy removals on understorey algae, mostly juvenile Macrocystis, Ecklonia and Carpophyllum spp, were highly dependent on the timing of canopy removals and the combinations of canopies removed. For example, winter harvests of the Macrocystis canopy alone enhanced the survival of post-settlement Macrocystis recruits, but had little effect on Ecklonia recruitment. However, when both Macrocystis and Ecklonia canopies were removed in spring, there was heavy recruitment of Ecklonia that grew to dominate the understorey. Strong inter and intraspecific interactions from the Macrocystis surface canopy appeared to have been reduced by physical factors including water turbidity, sedimentation and the deterioration of the surface canopy during summer. These physical factors were not as limiting in Tory Channel. Fine scale extrinsic factor effects including nutrients, light and grazing on the early life history of Macrocystis were investigated in small experiments. Results suggest that recruitment may be nutrient limited even at moderately low temperatures, and that small herbivorous gastropods are an important source of mortality in the early life stages of Macrocystis. Culturing and transplantation cultivation techniques were also examined as a means of supplementing algal supplies. Macrocystis was cultured successfully through its life cycle onto culture ropes, but generally failed to produce visible sporophytes when placed in the field. Cultured plants did grow in Tory Channel, however. Juvenile plants transplanted to ropes for on-farm cultivation showed little growth during summer, but the addition of nutrients significantly enhanced growth rates of these plants during warmer months when natural nutrient levels were low. Increased growth rates at the onset of winter and with the addition of nutrients during summer confirmed that low nutrient levels during summer are growth limiting. Akaroa Harbour kelp forests exhibited considerable variation in Macrocystis canopy biomass through time. For example, the 32,000 m2 kelp forest at Wainui had a biomass of 144 t in October 1995, which then decreased to 21 t in October 1996. Canopies tended to deteriorate during summer. Thus, at Ohinepaka Bay kelp forest had a biomass of 31 t during winter 1997, which decreased to 0.06 t the following summer. The greatest reduction in biomass, however, coincided with a period of hugely increased sediment, which smothered blades in the sea-surface canopy, covered the substratum, and prevented successful recruitment of kelp for over a year. Nutrient depletion was one of several factors thought to cause the summer deterioration of the Macrocystis sea-surface canopy, which has important ramifications for the commercial harvesting of Macrocystis pyrifera in summer. Management considerations and options are discussed in relation the commercial harvesting of Macrocystis in New Zealand. The major conclusion of this study is that although Macrocystis was able to form dense surface canopies during winter its ability to dominate kelp forests was constrained by physical factors, especially sedimentation, high turbidity, nutrients, and storms. The lack of strong interactions between Macrocystis and Ecklonia are also largely a result of their different life history characteristics. Overall, there appear to be no significant negative flow-on effects resulting from kelp harvesting and it appears that Macrocystis can be harvested sustainably.
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Phelps, Charlie. "Microbial diversity and function, and an exploration of bleaching in the Australian kelp Ecklonia Radiata." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2586.
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The kelp, Ecklonia radiata is the dominant, temperate macroalgae in the Great Southern Reef (GSR) of Australia. As a foundation species, the kelp provides a habitat for many marine organisms in the GSR benthic reef ecosystems. Macroalgae such as kelps host a dense biofilm, consisting of a compositionally and functionally diverse consortium of microbiota. The macroalgal host and its associated microbiome constitute a ‘holobiont’, where interactions can contribute towards the success and survival of both the microbial community and host. Despite the importance of E. radiata, and the tightknit relationship with its associated microbial community, describing and interpreting diversity and functionality of the microbial community is in its infancy. There is a need to further understand the dynamics of the microbial community composition and gene function, and how these vary over space and time. An understanding of natural variation is of critical importance when attempting to interpret the impact of environmental perturbations (for example, heat waves and eutrophication), which can cause shifts in microbial community composition in holobionts, and may result in dysbiosis, the proliferation of opportunistic pathogens, and eventually disease. Ecklonia radiata is documented to experience bleaching disease across its habitat range, however there are no comprehensive investigations as to the possible pathogens that are associated with E. radiata bleaching disease. Thus, the overarching aim of this thesis is to investigate the microbial diversity and function associated with E. radiata and the relationship with tissue bleaching on the kelp.
Using 16S rRNA gene amplicon sequencing, Chapter 2 aimed to (1) examine the temporal and spatial variations in the bacterial community of bacterial microbiota on the kelp E. radiata, and (2) investigate the relationship between environmental drivers and the bacterial community on kelp. These analyses revealed that over large geographical distances (∼3,300 kms), kelp microbiomes differed significantly, however within regions the community structure was relatively stable. The environmental factors that were measured somewhat influenced the community structure. A persistent core microbial community was identified with the same members dominating across regions, potentially suggesting these individuals play essential roles in maintaining host health. As such, it is imperative to define the key functional roles in the E. radiata microbiome and establishing key processes that maintain kelp holobiont health.
The E. radiata microbial gene function profile was then investigated through metagenome shotgun sequencing (Chapter 3). Here, I aimed to examine the functional repertoire of the bacterial community of the kelp and to identify what relationship, if any, there is between spatial (four sites in the NSW region) and temporal (seven bi-monthly time points, over a 17-month period) patterns in microbial function and associated environmental conditions. I identified several key functional pathways in the E. radiata microbiome, including pathways associated with defence response mechanisms, biogeochemical cycling and nutrient metabolism. Additionally, spatiotemporal differences in gene function composition were noted, and environmental drivers, in particular temperature, were found to influence the E. radiata microbial gene functional profile. These novel findings are fundamental in identifying the E. radiata holobiont functional processes and are critical in the understanding of the role microbes play in maintaining kelp health and the subsequent reef ecosystem.
The baseline microbial community composition and functioning can be altered, this generally occurs with extreme weather conditions and or anthropological disturbances such as eutrophication. When this occurs, host associated microbial communities can shift to a depreciated state, impacting the host, potentially exacerbating opportunistic pathogens, and facilitating disease. For E. radiata some taxa have been identified to be abundant on bleached kelp compared to healthy, but their role as pathogens has not been investigated. Koch’s postulates are a series of tests that aim to establish a causative relationship between disease and pathogens and are performed through a series of inoculation studies. In marine systems, a similar series of tests have been done in a range of studies to understand the role of individual strains of bacteria in diseases of corals, sponges and macroalgae, however, the methods among studies vary slightly in the way that the inoculation treatments are performed and controlled. In Chapter 4 I aimed to explore 1) the extent of confounding effects from bacterial growth media in inoculation studies of diseases of marine benthic organisms through a literature review; 2) the effect of bacterial growth media and its components on bleaching disease. The review identified confounding factors in previous inoculation studies, based on whether the putative pathogen cells were pre-treated prior to inoculation e.g., centrifuged washed and/or filtered and if a sterile media control was incorporated in the experimental design. I found that nutrient growth media used in inoculation studies contributes to bleaching disease in E. radiata and caused a shift in the overall microbial community composition. Furthermore, the microbial community composition was substantially altered when kelps were held in aquaria, in comparison to undisturbed kelps collected from the reef. These results were summarised into a framework recommending approaches for interpretating previous inoculation studies and for future inoculation research. The recommendations for future inoculation studies include having pre-treatment methods and controls to reduce nutrient addition. It is also recommended that the microbial community composition is assessed via a method such as 16S rRNA amplicon sequencing, to identify any shifts in the microbiome when moved from the reef into the aquaria. The range of knowledge obtained from this research has widened the understanding of kelp holobiont interactions and provided invaluable data and a tool that can advise and inform researchers and managers on changes in kelp health dynamics in projected climate change conditions in the future. Hence, the key findings identified in this thesis are an important contribution for kelp conservation and identify possible concepts for restoration efforts through understanding of the E. radiata holobiont.
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Thorsen, Maja Kristine. "The impact of kelp (Laminaria digitata) and other organic materials on machair soil and plant health." Thesis, University of Aberdeen, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600045.
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The machair of the Outer Hebrides, Scotland, is a cultural landscape, designated as a Site of Special Scientific Interest. Crofting on the machair is a sustainable low-input, low-output system, producing crops for livestock fodder, which has been practiced for hundreds of years. Recent demographic changes have affected the agricultural practices, with unknown, but potentially negative effects on these marginal soils. The present work investigated the effects of some of these changes in agricultural practices, in particular the effect of amendment with kelp (Laminaria digitata), a brown seaweed, ploughing and land use on soil stability, water repellency and soil microbiology. Furthermore, the effect of kelp on plant seed germination and root development was assessed. The results showed that machair soil is resilient towards amendment with kelp and synthetic NPK fertilizer in a single growing season, and that this resilience was not caused by rapid degradation of kelp. There was evidence that kelp inhibits soil fungi, but increases total microbial biomass and activity. The soil was slightly to severely water repellent. The causes of this repellency could be attributed to a number of factors including plant organic matter, manure, land use and organic matter within aggregates. Kelp increased seed germination in a number of key native machair plants and crops, suggesting that kelp may affect native plant community composition and crop yield. Also, a promoting effect on root development of kelp was seen in some plant species, with a threshold concentration above which it became inhibiting. Furthermore, these results confirmed the presence of plant growth regulators in kelp. The above findings are relevant not only to the machair, but also to other marginal sandy soils, and to the use of seaweed species as organic alternatives to conventional synthetic fertilizers.
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Rana, Shivani [Verfasser], Michael [Gutachter] Bonkowski, Ludwig [Gutachter] Eichinger, Becker [Gutachter] Burkhard, and Raimund [Gutachter] Wegener. "Genomics analyses in kelp species / Shivani Rana ; Gutachter: Michael Bonkowski, Ludwig Eichinger, Becker Burkhard, Raimund Wegener." Köln : Universitäts- und Stadtbibliothek Köln, 2020. http://d-nb.info/122853442X/34.
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Robertson-Andersson, Deborah. "A study of the distribution of algae in the Two Oceans Aquarium, Kelp Tank, Cape Town." Bachelor's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/26029.
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Five years have passed since the Two Oceans Aquarium, Cape Town, opened its doors for the first time in November 1995. Since then, a seaweed community has established itself in the Kelp tank. The seaweeds were brought in as either epiphytes on mature macro algae or as epiphytes on boulders that were placed on the floor of the tank. Thus, the community in the tank can be assumed to have established itself naturally. This study looked at the extent of the species diversity, zonation patterns in the tank (with particular reference to wall orientation), depth substrate type, plane (i.e. vertical or horizontal surfaces) and species distribution with depth. This was done by placing quadrats in transects down each wall and noting the percentage cover of each species. Quadrat depth, substrate type, wall orientation, and plane were noted. The percentage cover values as well as the environmental data were entered into CANOCO, an ordination programme for windows. Ordination showed that the tank was essentially a homogeneous environment with no difference in species distribution with regard to wall orientation, depth, substrate type, or plane. It was noted that self-seeded Ecklonia maxima were very unhealthy, small, deformed and had many epiphytes, with the exception of three plants that were growing under the plunger. From this it was concluded that water motion, and not light or nutrients, was limiting in the tank. Schimmelmannia elegans was found growing in the kelp tank. It had never been described as growing in South Africa previously. One theory was that the increased daylight length in the tank, caused by the fact that lights over the tank were often left on for extended periods, triggered a photoperiodic reproductive cue from the crustose phase (which was assumed to be growing unrecorded on the Cape Peninsular) for the sporophyte to grow. However, daylight length in the Kelp tank and Tristan da Cunha (where it was first recorded as growing) were the same so that theory was discarded. Another theory was that the algae was introduced into the tank in some way. This, however requires further investigation. Environmental conditions in the tank were investigated using aquarium records. Light intensity and duration, water temperature, pH, salinity, dissolved oxygen concentration were all found to be optimal for photosynthesis and growth to occur. Water motion was seen as the only limiting factor for photosynthesis and growth as it also has an effect on nutrient uptake. Grazer intensity was also examined. It was found that grazing by fish was stable; however, grazing by invertebrates and particularly mesa-herbivores could be increased, by adding more of them into the tank. It was found that with light being left on for functions there was no real seasonal change in light duration and this may be a problem for seaweeds that experience seasonal growth as they are missing seasonal cues. A management option of having a strictly controlled 11 hours of daylight during a winter month was proposed as a solution. This study is a good reference point for future work to be done on seaweed succession in the Kelp tank.
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Attwood, Colin Graham. "Investigations into the functioning of phytoplankton, zooplankton, kelp and benthic communities at the Prince Edward Islands." Master's thesis, University of Cape Town, 1991. http://hdl.handle.net/11427/21843.
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Abstract Several questions pertaining to the marine communities at the Prince Edward Islands are addressed. Firstly, the nature of the 'island-mass effect', and the cause of the frequently recorded diatom blooms in the area are examined. It had been suggested that the cause of the blooms is related to the presence of a Taylor Column-induced, low density, stationary eddy which stabilises the water column. On a cruise in April/May 1989, temperature, salinity, nutrients, chlorophyll and primary production were measured at 90 stations in a large grid centred on the islands. These, together with data collected on previous cruises, are used to show that the repeated occurrence of diatom blooms was not a result of nutrient enhancement. No evidence for light-limitation of phytoplankton was found. The evidence and theoretical basis which was used to predict the existence of a Taylor Column is questioned. An alternative hypothesis for explaining the blooms is presented. It is argued that these local blooms are simply the result of seeding by a dormant stock of diatom resting spores from the shallow sediments around the islands. This hypothesis hinges on three observations: (1) the blooms occur only over shallow sediments and are not a feature of the open ocean, (2) the species Chaetoceros radicans has been responsible for the bloom each time the cells were identified, and (3) C. radicans forms a rapidly sinking, heavily silicified, resting spore.
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Leitao, Daniela. "Effects of commercial kelp extract and plant growth regulators on growth of Gracilaria gracilis in culture." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/6707.
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The addition of a local commercial seaweed extract (Kelpak®) to crop plants has proven to be beneficial as it improves growth and yields. Its efficiency has been attributed to its production method that involves a cold process, resulting in a product containing significant amounts of plant growth regulators (auxins and cytokinins). The aim of this study was therefore to investigate the effects of this commercial seaweed concentrate (Kelpak®) on the growth of Gracilaria gracilis (Stackhouse) Steentoft, Irvine et Farnham, with a view to the potential in mariculture, especially as this red seaweed is currently under cultivation in South Africa as feed in abalone aquaculture.
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Temple, Wayne Douglas. "The use of the kelp, Macrocystis integrifolia, as a soil amendment and foliar spray upon selected crops." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29306.
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In this investigation the coastal B.C. kelp, Macrocystis integrifolia, was evaluated for its potential use as a soil amendment and foliar spray in crop production.
The kelp soil amendment was applied fresh to a fine-textured deltaic soil with applications of 0, 7.5, 15, 30, 60 and 120 t ha⁻¹. Soil chemical, physical, crop growth and nutritional responses were characterized over a two year period. Beans (Phaseolus vulgaris) were planted in the first year and peas (Pisum sativum) were planted in the second year. Plant growth responses included reduced yields, emergence and flowering with the 120 t ha⁻¹ application and increased plant moisture content with increasing kelp applications. Nutritional responses included increased plant elemental concentrations and uptakes of Na, K and Cl with increasing soil applications of kelp. Soil responses to increasing applications of kelp included sharp increases in soil water-soluble salts, Cl , NO₃-N, exchangeable K and Na, and a decline in soil pH. Subsequent greenhouse experiments suggested that phytotoxic effects from the 120 t ha⁻¹ kelp applications were primarily induced by high levels of soluble salts, but an unknown phytotoxic substance may be implicated. Soil aeration increased with kelp application up to 60 t ha⁻¹, but declined with the 120 t ha⁻¹ application.
The use of KL inteqrifolia as a processed concentrate for subsequent dilution with water and foliar application (2 and 4 L ha⁻¹) to the bean (P. vulgaris) crop resulted in increased harvestable bean yields in each of two field seasons. Evidence is presented which supports the theory that growth promoting phytohormone-like substances extracted from the kelp may, in part, be active constituents of the kelp concentrate. Field crop nutritional responses to kelp foliar sprays included reduced shoot elemental concentrations, but increased uptakes, suggesting greater dry matter accumulation per unit element. Crop growth and nutritional responses between growing seasons were not consistent. A greenhouse experiment demonstrated that many of the kelp foliar spray effects upon crop growth, development and nutrition could be dependent on soil moisture regimes.Land and Food Systems, Faculty of
Graduate
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Milligan, Kristen L. D. "Effects of wave exposure on an intertidal kelp species Hedophyllum sessile (C. agardh) Setchell, demographics and biomechanics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34589.pdf.
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Muchena, Lindsay. "Improved growth of hydroponically-grown rough lemon (Citrus jambhiri Lush) seedlings treated with kelp and vermi extracts." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65918.
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A substantial number of South African citrus trees are rooted on rough lemon rootstocks. In order to ensure the successful establishment of a high percentage of young citrus trees, it is necessary to ensure that farmers are provided with young vigorous nursery trees that have a large and healthy root system. Vermicast extracts (VE) and liquid extracts from the giant seaweed, Ecklonia maxima (EM), have been used on various crops over the past decades to promote plant growth and development. It is widely reported that plant growth, seedling vigour, water-use efficiency and nutrient-uptake of these crops improves with EM and VE treatments, thereby reducing excessive fertiliser applications. With the improved uptake of nutrients such as nitrogen (N), which is the main component of chloroplasts and proteins involved in the Calvin cycle, it is likely that the application of EM and VE to plants could lead to an improvement in the photosynthetic capacity of plants. The benefits from applications of EM and VE have been attributed to the presence of plant growth regulators/hormones (PGRs) such as auxins and cytokinins. Since seaweed extracts are manufactured using different methods, some of which may include the use of elevated temperatures, acid and/or alkaline hydrolysis of plant material, it is not surprising that different seaweed extracts may contain various levels of PGRs which can lead to dissimilarities in their growth promoting effects. A hydroponic experiment was conducted to test if locally produced EM from two different suppliers and VE would increase root length, root volume, root dry mass, stem diameter, plant height, chlorophyll content, nutrient uptake and photosynthetic capacity of rough lemon seedlings. The other objective of this study was to determine if there was any difference in growth promoting effects of EM obtained from two different supplies due to the difference in the levels of plant growth regulators they contain. Since the action of EM and VE is dose dependant, it was also necessary to determine the optimum concentration of EM and VE for the growth of rough lemon seedlings. This experiment was conducted in a glasshouse at the University of Pretoria experimental farm. Liquefied Ecklonia maxima from different manufactures; Ecklonia maxima - Kelpak® and Ecklonia maxima – Afrikelp® (EM1 & EM2 respectively); and vermicast extracts (VE) were applied separately to rough lemon seedlings as a drench (at 0.5%, 1% and 2% dilutions), at 14 day intervals. Deionized water and full strength Hoagland solution were used as controls. Root volume, root length, stem diameter, plant height, chlorophyll content and photosynthesis were measured weekly for 12 weeks. At the end of the trial, the average root dry mass and shoot dry mass for each treatment was determined. Upon termination of the trial, oven dried leaf samples were analysed for nitrogen (N), phosphorus (P), potassium (K) and calcium (Ca). N analysis was done at an accredited commercial lab whilst P, K and Ca analyses were done at the University of Pretoria using ICP-OES.Dissertation (MSc (Agric))--University of Pretoria, 2017.
Plant Production and Soil Science
MSc (Agric)
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Morris, Kathryn. "Kelp forests in False Bay: urchins vs. macroalgae in South Africa's south-west coast biogeographical transition zone." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25072.
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There is ongoing global concern over unwanted regime shifts in marine systems. Shifts from diverse and productive algal-dominated ecosystems to less productive urchin and coralline-dominated temperate reefs are becoming increasingly common. Kelp forests found along South Africa's south-west coast between Cape Point and Cape Agulhas occur in a region of biogeographical overlap. They are commonly referred to as transition zone kelp forests and are dynamic ecosystems that are particularly susceptible to grazing influence from species such as sea urchins. This study (1) explores the uniformity of these transition zone kelp forests along the western side of False Bay, with a focus on macroalgae and urchins, (2) identifies a threshold in urchin density above which algal abundance declines and (3) seeks to identify relationships between attached and drift algal abundance. Twenty replicate quadrats were sampled in six kelp forests along the western side of False Bay. Within each quadrat, urchins (Parechinus angulosus) and kelps (Ecklonia maxima) were counted, percentage covers of various understorey algal species were recorded and drift algae were collected. Although there was significant variability in algal and urchin cover across the six sites, kelps generally increased from north to south, while urchins did the opposite. Urchins were negatively correlated with algal communities, and a localised threshold of 1.43kg/m² (50 urchins/m²) was identified, above which attached kelp density failed to increase above 10/m² and percentage cover of understorey algae usually remained below 20%. Surprisingly, no relationship was discovered between abundance of drift kelp and attached kelp, understorey algae or urchin density. This result was likely distorted by the naturally turbulent conditions of South African waters. Results highlight the complexity of these cool-water environments. To better understand the role of urchins in this system, experimental research into the feeding behaviour and effect of P. angulosus on kelps and understorey seaweeds in the presence/absence of drift algae is advised.
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Brauer, John Marius. "Nutrient uptake and exudation patterns of nitrogenous substances and polyphenols in the kelp Ecklonia Maxima (Osbeck) Papenfuss." Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/21940.
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Bibliography: pages 132-140.Exudation patterns of organically bound nitrogen and polyphenol substances, as well as the uptake of nitrate, ammonium and phosphate were studied in the kelp Ecklonia maxima (Phaeophyceae) in ex-situ experiments. It was found that exudation of organic materials only rarely followed a straight accumulatory trend ; fluctuations of kelp-derived substances occurred as a net result of pulsating production patterns coupled with differential rates of utilization by marine heterotrophic organisms. Pulsing took place at irregular intervals in different plants, precluding statistical treatment of exudation. The observed initial pulsing liberation of DON and polyphenols, affected the quantification of exudation rates which could only be tentatively determined. Antibiotic agents used in one experiment did not succeed in controlling free-living bacteria in the water column without affecting the kelp DOM production was diminished in the presence of antibiotics, leading to the conclusion that they affected the physiology of the epidermal cells. This provides indirect evidence that exudation is an energy-dependent, active process. Measurements of uptake velocities of ambient and enriched nitrogen established that there was a higher affinity for ammonium as a nitrogen source than for nitrate at enriched N levels. At ambient nutrient levels, nitrate uptake velocities were 1,5 times higher than those for ammonium, making nitrate the primary nitrogen resource of E. maxima. However, the uptake potential for either source was not competitively inhibited by the other. Ammonium and nitrate uptake velocities still increased from enriched levels of 30-40 uM N to approximately 100 uM N. Both exudation and uptake phenomena were subject to seasonality: During summer, the rates for exudation and uptake were found to be higher than in winter, which is known to be a dormant phase in the growth of E. maxima. A comparative analysis of dissolved free amino acids in the water surrounding the kelp and a tissue analysis of free amino acids obtained under enriched conditions showed that alanine was prominent b6th in the thallus and in the water. Glutamic acid was detected in the water only after the kelp had been introduced during a nitrogen feeding experiment and appeared to be GS/GOGAT derived. Aspartine was al so detected at high relative concentrations. Polyphenolic substances (phlorotannins) accumulated in exudates of E. maxima more readily due to the low biodegradability of these compounds and contributed to the yellow colouration and uvabsorption characteristics (Gelbstoff) of the surrounding water.
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Rand, Andrew M. "Using Geographic Information Systems and remote sensing to improve the management of kelp resources in South Africa." Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/6165.
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Includes bibliographical references.In 2002 the Department of Environmental Affairs and Tourism (DEA&T), Marine and Coastal Management (M&CM) and the Seaweed Unit undertook a program to document the localities and quantities of the standing crop of the economically important kelps, Ecklonia maxima and Laminaria pallida, in the fourteen commercial seaweed Concession Areas that contain commercial quantities of kelps. The primary objective of this study was to establish a coastal kelp resource database for the South African coastline from Cape Agulhas to the Orange River (the international border with Namibia). The method was designed to integrate past and current analysis of multi-year kelp data from commercial harvesting, biomass and kelp bed extent while allowing for the integration of future surveys within the inventories.
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Belseth, Elen. "Eco-physiology of the Arctic kelp Laminaria solidungula : - using divers, Remotely Operated Vehicle and Pulse Amplitude Modulated fluorometry." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16364.
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McGarigal, Caitlin R. "Physiological and Behavioral Effects of Angling Stress on Kelp Bass, Paralabrax clathratus, an Important Gamefish in Southern California." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10825934.
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Gamefish populations in North America are experiencing increasingly elevated recreational fishing pressures; however, the impacts of current fishing regulations have not been evaluated for most marine species. Mandatory catch and release often results from size and bag limits with the assumption of fish survival and recovery with minimal sublethal effects. Depending on the intensity and duration of the stressor, acute stress from angling and handling can have deleterious physiological and behavioral impacts with consequences for fish health and fitness. We evaluated the short-term sublethal effects of angling-related stressors on kelp bass, Paralabrax clathratus, one of the most popular gamefish in southern California. Collaborating with recreational anglers to capture fish using standard hook and line practices, we evaluated biochemical responses and recovery by collecting blood samples at different time points after capture (10-120 min), after fish were released and some were recaptured (3h to 186 d). Blood cortisol, glucose, and lactate were significantly elevated and steadily increased in the hour following capture and holding (p < 0.001). Fish caught, released, and recaptured after varying time at liberty were found to have returned to basal levels in < 24 h (p > 0.05). Physiological stress responses were positively correlated with angling and handling duration, but negatively correlated with increasing fish size (p < 0.05), suggesting that larger individuals may be more resilient to capture stress. Likewise, kelp bass exhibited no signs of cumulative or chronic stress from repetitive angling/recapture events and recovered to basal levels in <24 h (p > 0.05). Kelp bass were also tagged with acoustic accelerometer transmitters and tracked to evaluate fine-scale behavioral effects of angling stress on their normal diel movement and activity. Reduced frequency of high acceleration movements (i.e. rapid feeding strikes) was observed for 33 h post-release, followed by recovery and evidence of elevated feeding behavioral activity. Rate of movement and area use size showed high individual and temporal variation; however, reduced movement immediately after release steady increased to normal levels over the first 10 h post-release. There was no discernable effect of angling on area use size, but areas of high relief substratum may be important refuge habitat for angled kelp bass during recovery. By integrating physiological and behavioral endpoints for kelp bass to standard angling induced stress we conclude that this species is able to recover in <24 h; however, smaller individuals may be more susceptible to predation during this recovery period. Based on these findings, it is likely that kelp bass may still fair well under current size and bag limits.