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

The major constituents of the plankton, phytoplankton, cladocera, copepods and chaetognaths, sampled in the 1951 oceanographic survey of the British Columbia Inlets are reported in concentrations per cubic meter of water. Horizontal plankton tows sampled four depths, 5, 21, 32 and 47 feet, respectively. The distribution of each group is discussed in relation to the hydrographic data and the present theory of inlet circulation. The inlets investigated fall into two general groups, (a) those which are long and have a large freshwater discharge at the head and (b) those which have a small freshwater discharge and are short. The data from six inlets making up the former have been grouped together and are discussed as the Average Inlet. Those inlets making up the latter group are classified under the general heading of atypical inlets; each is discussed separately. In the Average Inlet the plankton volumes were the greatest at the mouth, particularly towards the surface. The concentration of plankton is shown to be a result of local phytoplankton production. In the absence of currents the phytoplankton are shown to be limited vertically by density. The zooplankton are divided into three groups on the basis of their response to the physical factors. The distribution of cladocera indicates that it is positively phototropic while that of the copepods and chaetognaths indicate that that they are negatively phototropic. The chaetognaths are found to be absent from all the atypical inlets, the cladocera from three. The copepods are concentrated at the depth which is associated with the compensation light intensity. Attention is drawn to the fact that this report is a qualitative description of the relationship between the distribution of the plankton and the physical oceanographic conditions. Future surveys will have to sample more extensively and intensively. / Science, Faculty of / Zoology, Department of / Graduate

The northern Strait of Georgia (NSG) and adjacent Malaspina Complex of inlets (MC) were studied to determine the effect of stratification on microplankton communities. The NSG was dominated by nanoflagellates in spring. There was no evidence of a vernal diatom bloom in the Strait, perhaps due to wind turbulence or microzooplankton grazing. In early summer regimes were conducive to diatom growth but the northern Strait was experiencing a "mild" red tide. By late summer, diatoms bloomed and prevailed, presumably, till the fall decline. Stratification was greatest in late summer, due chiefly to temperature, with reduced surface salinities on the east side from Fraser River runoff. At this time biological partitioning was pronounced, resulting in a mosaic of organismal groups. Although stratification had declined by early autumn, the mosaicism was maintained and strengthened. Diatoms were most abundant in the north and on the west side where stratification was least, in areas of tidal turbulence. Photosynthetic nanoflagellates and photosynthetic dinoflagellates favoured the more stratified east side. Ciliate distributions mirrored those of the nanoflagellates. The MC was thought to be a more stratified version of the NSG but it was found to be a fairly mixed water body due to tidal action. It was sheltered from winds which allowed the early blooming of diatoms. These were maintained for several months by a tidal jet through Malaspina Inlet that probably injected nutrients into the junction of Malaspina, Okeover, and Lancelot Inlets. Principal components analysis was used to reduce the dimensionality of the biological dataset, and canonical correlation analysis allowed the coupling of environmental data to the biological principal components. It was found that PCI reflected general biomass while PC's II and III were most often related to depth and location. These latter two were utilised to resolve the species information in three-dimensions. In general, nanoflagellates populated surface waters whereas diatoms tended to occupy deeper depths. Multiple regression analysis was performed on organismal groups to explore how biomass was affected by stratification, pycnocline depth, surface temperature (seasonality), nitrate, and grazing. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

In-situ measurements of surface chlorophyll and zooplankton concentration are compared with in-situ hydrographic measurements and infrared satellite images of the west coast of British Columbia. Their relationships are quantified for a mid-summer and an early winter study period. Winter in-situ hydrographic data showed the shelf to be dominated by Vancouver Island Coastal Current water near-shore, Davidson Current water over the middle shelf, a frontal zone separating these regimes, and North Pacific water over the shelf break. The summer shelf was dominated by topographically induced upwelling in the southern portion of the shelf and stratified regions over the outer shelf and shallow banks further north. Strong northwest winds late in the summer study period induced upwelling along the entire shelf. The surface thermal signature of each of these regimes was identifiable in the satellite imagery. Maximum winter concentrations of chlorophyll and zooplankton were associated with Vancouver Island Coastal Current water and southern portions of the frontal zone. Davidson Current water consistently had the lowest chlorophyll concentrations in the winter study area. Zooplankton concentrations decreased with increasing temperature and distance from shore. The correlation of loge transformed zooplankton concentrations with surface temperature allowed the satellite imagery to explain 49% of the sampled variance. The association of specific chlorophyll concentrations with each hydrographic regime enabled the satellite imagery, in conjunction with an image derived salinity model, to explain 55% of the sampled variance. Image derived plankton models allowed a spatial representation of predicted plankton concentration and the model error. Summer zooplankton concentrations were not consistently related to satellite measured surface temperature but showed a qualitative association with higher chlorophyll concentrations around the outer edge of the upwelling area. Minimum chlorophyll concentrations were found in warm, stratified surface water and intermediate concentrations in the coldest, most recently upwelled water. Maximum concentrations occurred at intermediate temperatures. A least squares fit non-linear equation showed the satellite measured surface temperature patterns explained 72% of the sampled loge transformed chlorophyll variance. Distributions of both zooplankton and chlorophyll concentration retained their association with patterns of sea surface temperature during a wind driven upwelling event. Multivariate cluster analysis of zooplankton taxonomic groups during both winter and summer showed spatial patterns of community composition matched satellite measured patterns of sea surface temperature over the middle and inner shelf. Over the outer shelf, spatial patterns of community structure appeared more closely associated with depth than surface thermal patterns. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate