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.

[No abstract available] / Science, Faculty of / Zoology, Department of / Graduate

A study of plankton communities in the Strait of Georgia was undertaken in order to determine qualitatively and quantitatively the distribution in time and space of both zooplankton and phytoplankton. In order to gain some picture of the seasonal, variations in the plankton communities two cruises were made in the Strait, one in June, 1955, and the other in November 1955. 165 plankton collections were taken. A complete count of zooplankton organisms was made in 5cc. of each sample and the number of diatoms cells per liter was tabulated. Copepods and diatoms were analysed to species; other groups to class or genera. Surface temperatures were taken. The physical and chemical data, used to account for the biological distributions were obtained largely from oceanographic data already available for the area. The correlation of these data have resulted in a number of conclusions concerning the distribution of plankton in the Strait of Georgia. The chief factor affecting the general distribution of plankton in the Strait of Georgia is the salinity gradient. The inflow of fresh water from the Fraser River forms zones of varying properties, and leads to the development of different plankton communities. The extent to which physical and chemical factors may determine the presence or absence of certain organisms from the zones described is discussed. / Science, Faculty of / Zoology, Department of / Graduate

The planktonic algae and protozoa of Indian-Arm, a coastal, fjord-type inlet near Vancouver, British Columbia, was studied for a year to determine the species composition and their distribution patterns, and to investigate factors influencing these features. Several physico-chemical factors were monitered concurrently to investigate their influence upon protoplankton ecology. Light attenuation characteristics of the water were determined to learn the spatial and temporal variations of water turbidity and its relation to protoplankton. The environmental parameters investigated monthly at a series of seven stations were temperature, salinity, oxygen, Secchi disc depth, and light attenuation coefficients (alpha). These data were supplemented by the observations of earlier workers on insolation, light penetration, nutrients, and runoff. The presence of a pycnocline (sharp density gradient) in the euphotic zone substantially reduced the rate of downward transport of passive protoplankters by turbulent mixing. Four "seasons" in light penetration were recognizable. These seasons were governed by insolation and concentration of runoff-borne seston (total suspended particles) and resident seston. Intrusions of sea water, necessitated by the surface outflow of brackish water, could be traced by their relatively high turbidity. The correlation of alpha with seston in Indian Arm waters was investigated. A linear positive correlation was found but it was unsatisfactory for measuring seston with the alpha-meter because of the heterogeneous nature of the seston. Surface current patterns were studied four times (in December, January, May and July) using drift buoys, The patterns in the upper meter of water were complicated. The protoplankton studied included all sizes smaller than 500μ. Emphasis was placed upon the smaller of these (i.e. smaller than 60 μ.) because of an earlier report that less than 10% of the primary production in Indian Arm was by "net plankton". The spatial and temporal distribution of the individual taxa was studied using a total of 180 water samples and 60 net samples collected monthly at five stations. The greatest numbers of taxa and of individuals were found in the pycnocline region and immediately below it (in the top 15 m). The surface layer appeared to be selective for eurythermal and euryhaline organisms, The pycnoclinic community was predominated by heterotrophs in September to February, photoautotrophs in March to May, and a mixture of all trophic types in June to August. Significant quantities of plankton were carried into Indian Arm by sea water intrusions and could contribute to the living biota or to the pool of nutrients known to accumulate rapidly in the deep basin. Surface outflow was a major factor in the removal of protoplankton from the euphotic zone and in the replenishment of nutrients. The rate of population depletion, together with the reproductive rate determined the success of any species. The evidence indicated that the two main factors regulating protoplankton standing stock and primary production in Indian Arm were (a) runoff-induced surface outflow, and (b) insolation. The total protoplankton complement was analysed monthly, counting the number of taxa which belonged in the different categories of taxonomic classification, size, ecological importance, origin, nature of the pelagic state, natural habitat, and trophic type. The taxa were assigned to the categories by subjective and objective means, employing the literature and original observations. Over the entire year, the most richly represented taxonomic category was the class Bacillariophyceae (122 taxa) followed by the classes Dinophyceae (91, of which 70 were "Armoured"), Ciliatea (44), and Chrysophyceae (15). More than half of all taxa for the year were photoautotrophic. The second largest category was composed of pure heterotrophs. Many others were myxotrophic (capable of both autotrophic and heterotrophic acquisition of energy). Over half of all taxa were at least partly less than 60μ in size. These taxa included the most numerically abundant. The ecological importance of most taxa was considered to be "negligible". The nature of the pelagic state of most taxa was holoplanktonic, the natural habitat of most was neritic, and the origin of most was endemic (local). The records of occurrence of taxa in the water samples were analysed to detect recurrent groups by computing the index of joint occurrence for 80 taxa. The analysis revealed three major recurrent groups, containing 20 taxa in all and distinguished by seasonal occurrence or vertical distribution, as dictated by nutrition or both. The information gained during the study and from the literature was synthesized into diagrams of the probable energy cycle in the Indian Arm ecosystem. / Science, Faculty of / Botany, Department of / Graduate

A comparison was made of the responses of benthic and planktonic components of natural water-sediment systems enriched with inorganic fertilizers. Three levels of fertilization were applied to a series of enclosures placed in a shallow (1 m depth) area of Marion Lake, British Columbia and community respiration, primary production, standing algal crop and the distribution of added phosphorus were measured in both the sediment and the water column over a period of two years. A loss of added phosphorus from the water column corresponded to an increase measured in the sediment. Uptake and release of phosphorus by the sediment was proportional to its concentration in the water column, indicating a water-sediment equilibrium. In an undisturbed system, however, there was a net movement of phosphorus into the sediment . A sustained high level of planktonic primary production persisted throughout the period of fertilization. However, an initial increase in total benthic primary production returned to pre-fertilization levels following the establishment of an increased standing crop of epipelic algae. At this point, benthic primary production appeared to be a function of grazing pressure, responding to increased grazing but not to additional fertilization. When grazing was experimentally increased by concentrating grazers in an experimental area, benthic primary production increased. Fertilized sediment appeared to have a much greater ability to withstand increased grazing pressure than normal sediment, maintaining high levels of primary production even at five times normal grazer density. But despite this potential, measurements of grazer and bacteria populations within the experimental enclosures showed no response to the greater standing crop of epipelic algae. As a result, sustained increase in benthic primary production could be induced only experiment-, ally. It was concluded that the benthic community was more stable in its response to enrichment than that of the plankton and by absorbing nutrients from the water column served to dampen the effects of the more pronounced fluctuations of the planktonic community. / Science, Faculty of / Zoology, Department of / Graduate

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