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.

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.

Thesis (Ph. D.)--University of California, Santa Cruz, 1976. / Includes bibliographical references (leaves 165-173).

Thesis (Ph. D.)--Oregon State University, 1986. / Includes bibliographical references (leaves 125-135).

In integrated multi-trophic aquaculture (IMTA) production of cultured species may not align temporally. For instance, at an IMTA site in Kyuquot Sound, BC where the cultured species are Anoplopoma fimbria (sablefish), Plactopentin yesoensis (Japanese scallop) and Saccharina latissima (sugar kelp), sablefish are grown year round while the kelp culturing lasts from winter to summer. Kelp sporophytes become visible in early spring while harvest takes place in July. This indicates that at Surprise Island the time period of nutrient extraction by the kelp is limited to only a few months per year. Two potentials methods to lengthen the time in which the kelp component was on site were employed and evaluated: 1. the use of multiple kelp species with potentially differing seasonal growth strategies and; 2. outplanting kelp seed at four different times of the year. The first method involved outplanting seed of four kelp species, Saccharina latissima, Costaria costata, Alaria marginata and Saccharina groenlandica and monitoring growth parameters (blade length and yield). For the second method, a modified seed production method of Merrill and Gillingham (1991) with Luning and Dring (1973) successfully provided seed throughout the year. Seasonally out-planted seed was also monitored for growth parameters. Results were marginal for experiments and were confounded by the lack of growth rates due to infrastructure problems, grazing by naturally setting marine snails and seemingly poor environmental conditions for kelp culturing at the farm site. However, data indicated that certain species in co-culture may slightly increase the time period, and strategically entered kelp seed may do the same. In particular the co-culture of C. costaria and S. groenlandica or biannual seed outplanting in fall and spring may increase the length of growth period of kelp provided certain limitations found during this experiment are overcome (i.e. pressures of grazing). Additional potential benefits with these kelp production strategies are the diversification of final kelp products, additional kelp harvests and increased production. / Graduate

Tesis par optar al grado de Magíster en Ciencias de la Ingeniería, Mención Química / Memoria 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.

Ingeniera Civil en Biotecnología / Este 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.

Underwater acoustics has recently emerged as a viable tool for assessing ecosystem health and exploring the estuarine soundscape. Recent acoustic surveys have mapped distributions of both seagrass meadows and kelp forests, and scientists are currently developing remote sensing capabilities to improve ecological assessments of these communities. Furthermore, researchers are beginning to focus on the propagation and ecological significance of bioacoustic signals within estuarine landscapes. The research presented here includes a thorough examination of the interaction of acoustic energy and macrophyte tissue as it pertains to habitat assessment and ecosystem function. Modeling experiments investigated the interaction of acoustic energy and submerged macrophyte tissue. Both seagrasses and kelp exhibited a similar acoustic response by increasing the acoustic compressibility of a seawater medium. The increase in acoustic compressibility was driven by free-gas volumes contained within the macrophyte tissue. Interestingly, the tissue served to limit the acoustic compressibility of the gas volume below the magnitude predicted by effective medium models. Separate inquiries of high-frequency sound propagation and the seagrass canopy revealed a significant temporal component to acoustic transmission. Specifically, sound transmission throughout a seagrass canopy was altered by the formation of free gas bubbles and the pressurization of aerenchyma channels, which was mediated by photosynthesis. The photosynthetic controls on sound propagation were species-specific, and patterns of acoustic transmission provided a reasonable proxy for gross primary production in Syringodium filiforme plants. Finally, the interaction of sound energy and submerged macrophytes appears to have important ecological implications. This research suggests that seagrass meadows scatter high-frequency sound energy and provide an acoustic refuge to fish from marine mammal predators. This refuge is highly seasonal, specific to different seagrass species and dependent on the abundance of above-ground biomass. Seagrasses also may influence the transmission of low-frequency sounds used by soniferous fish. Propagation characteristics of low-frequency sounds are highly dependent on frequency and result in differential transmission distances among individual fish species. It is clear from this body of work that submerged macrophytes are an important feature of the underwater soundscape. Future research should continue to exploit this feature for remote sensing purposes and examine its ecological significance. / text

Thesis (M.A.)--California State University, Fresno, 1980. / Includes bibliographical references (leaves [104]-108).

Thesis (Ph. D.)--University of California, 1959. / Bibliography: leaves 62-65.