This study aims to investigate both the distribution and character of particulate organic carbon (PIC) and particulate inorganic carbon (PIC) in the suspended sediment in the Gaoping estuary and its river plume. Furthermore, this study aims to investigate the tidal influence in the estuary and its plume by studying the size of sediment and the concentration of chlorophyll-a. In this study, suspended sediment, is mainly collected by multi-sieve filter, Catnet, which is used for the determinations of sediment size, organic carbon, inorganic carbon, as well as chlorophyll-a. The result shows that fine particle (<10 £gm) contributes more than 50% of the total weight in 5 suspended sediment groups (>153, 63-153, 10-63, 3-10, and 0.7-3), indicating that the PIC and POC are mainly controlled by the amount of fine particle. This suggests that fine particle is the carrier of the PIC and the POC, thus distributions of PIC and POC will be influenced as concentrations of the fine particle is influenced by environmental factors. In dry season, POC concentration is higher than in wet season; moreover, the concentration of POC beneath is higher than the surface, suggesting the influence of TSM. The distributions of suspended sediment are similar in both wet and dry seasons in size of <10 £gm, indicating there is no seasonal influence in the size of suspended sediment in our study areas. The PIC concentration in dry season is higher than the wet seasons, where the surface PIC concentration is higher than the beneath concentration in both dry and wet seasons, suggesting dissolution of PIC during settle down. The PIC mainly contributes by the fine particle (<10 £gm) which does not suffer any seasonal change. The TSM, POC, as well as PIC in suspended sediment in the Gaoping estuary and its plume are mainly contributed by fine particles. Distributions of these fine particles are highly influenced by the tides, but not the season changes. This study shows that the distributions of TSM, POC, as well as PIC in suspended sediments can be known through the characters of the suspended sediment.

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Models of primary production require parameters to describe photosynthesis as a function of irradiance, such as the saturation irradiance (Ek, ?mol photons m-2 s-1). However, this parameter varies in both time and space, is expensive to measure, and its variability in the oceans is not well described. A novel fluorescence-based approach is presented to determine an empirical parameter (EFT, ?mol photons m-2 s-1), which is strongly correlated with Ek. This correlation provides evidence to use EFT as a proxy for Ek. Using an autonomous profiling instrument package (SeaHorseTM, located on the Scotian Shelf) and an autonomous oceanographic observational buoy (Land/Ocean Biogeochemical Observatory, located in the Northwest Arm, N.S., Canada), the variability of EFT was examined on three time scales: hours, days, and seasons. Studying variations of EFT with these autonomous instruments provided insights to its variability on time scales relevant to models of primary production.

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Cette recherche comprend l'etude de la bioacatalyse de la chlorophyllase partiellement purifiee a partir d'algue (Phaeodactylum tricornutum) dans differents milieux organiques incluant les solvants miscibles et non miscibles a l'eau et les systemes micellaires tertiaires. Les quantites optimales d'eau et de solvant, choisi en fonction de son degre d'hydrophobicite et incluant l'acetone, l'ethanol, le propanol, le butanol, le pentanol, l'hexanol, le toluene, le pentane, l'hexane, l'heptane et l'octane, necessaire a la catalyse de l'effet hydrolytique de la chlorophyllase, ont ete mesurees. Les valeurs d $V sb{ rm max}$ obtenues mesurant l'activite hydrolytique de la chlorophyllase sont plus elevees chez les solvants miscibles a l'eau (log P 0.8). L'activite hydrolytique de la chlorophyllase decroit d'approximativement 12 fois lorsque le nombre de carbone pour les alcools, passent de 2 a 5. Certains resultats a partir du FTIR ("Fourier transform infrared spectroscopy") tendent a montrer que le phytol pourrait agir comme un donneur d'electron, ainsi, si un compose nucleophilique approprie est ajoute a un syteme biphasique, la solubilite de la chlorophylle dans l'hexane augmentera et l'activite hydrolytique de la chlorophyllase augmentera. En milieu biphasique (hexane/eau), l'addition de solvants polaires tels que l'acetone, l'ethanol, et le propanol augmente l'activite de la chlorophyllase et ce seulement a certaines concentrations. La mesure optimale de l'activite hydrolytique de la chlorophyllase en milieu micellaire tertiaire (tampon/hexane/surfactant) utilisant les polysorbates et les Spans ainsi que differentes chai nes hydrophobiques comme surfactant indique que les concentrations necessaires de surfactants sont dependantes a la fois de la chai ne hydrophobique et du groupement polaire. Toutefois, l'utilisation du Span 85 s'est avere plus approprie et les valeurs de $V sb{ rm max}$ obtenues mesurant l'activite enzymatique de la chlorophyllase sont 288 fois

Biomass production of chlorophyllase of the marine alga (Phaeodactylum tricornutum) at the exponential and stationary stages was performed. The results demonstrated that the biomass yield at the stationary stage was three times that of the exponential stage. A procedure for the extraction and purification of chlorophylls from fresh spinach leaves, used as substrate, was also developed. Chlorophyllase was extracted from photosynthetic membranes of the disrupted cells and partially purified. The purification procedure resulted into 70-fold increase in enzyme activity. Further purification of the partially purified enzyme was performed, using preparative isoelectric focusing on Rotofor-Cell System. Three enzyme fractions, FI$ sp prime$, FII$ sp prime$, and FIII$ sp prime$ were separated, however, most of enzyme activity (84%) was located in fraction FII$ sp prime$. The partially purified chlorophyllase was further purified by native preparative gel electrophoresis on Prep-Cell System, which resulted into a single active fraction. The purified enzyme fraction was then subjected to further purification, using automated Fast Protein Liquid Chromatography (FPLC) System, on ion-exchange Mono Q HR 5/5 column. The purification procedure resulted into two well separated isozymes, FI$ sp prime$ and FII$ sp prime$. Enzyme fraction (FI$ sp prime$) showed the highest enzymatic activity compared to FII$ sp prime$. The homogeneity of each fraction was demonstrated by a single protein band on SDS-PAGE. The molecular weights of these fractions FI$ sp prime$ and FII$ sp prime$ were 67 kD and 66kD, respectively. The optimum pH for chlorophyllase activity fractions FI$ sp prime$, and FII$ sp prime$ were 8.0 and 8.3, respectively. The enzymatic fraction FI$ sp prime$ showed higher activity towards commercial purified chlorophyll b when it was compared to that with the crude chlorophyll, partially purified chlorophyll and commercial purified chlorophyll a. However, enzymatic fraction FI

Graduation date: 1967