The seasonal pattern of ice motion in response to wind forcing and potential consequences to upwelling on the Mackenzie Shelf are considered using satellite-derived ice motion data from the National Snow and Ice Data Center and the NCEP 10 m wind data. The frequency of strong upwelling-favorable alongshore ice motion is high in early winter (November and December) compared to middle and late winter (January to May).For periods when the alongshore component of the wind is upwelling-favorable, the ratio of ice drift divided by wind speed on the Mackenzie Shelf is 0.024 in November and0.008 in March; we conjecture that this ratio decreases as winter progresses because the internal ice stress becomes stronger as both ice thickness and ice concentration increase. This constitutes a possible 10-fold decrease in the seasonal transmission of wind stress to the underlying water from November to March. This ratio in May (0.015) is higher than that in March. We suggest that it is because the internal ice stress becomes weaker as ice concentration decreases on the Mackenzie Shelf in May. Hence, under the same wind forcing, the potential for winter upwelling on Mackenzie Shelf may be enhanced if climate warming results in reduced ice thickness and/or ice concentration. Numerical model results show that the stress on the shelf could be reduced because of the internal ice stress from the pack ice over the deep ocean when the ice moves like a rigid body. We found that the model results are not realistic when the ice strength is 5,000 Nm-2. When the ice strength is 27,500 Nm-2, the model results are more realistic. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Resource subsidies are flows of nutrients from one ecosystem to another. Sandy beach ecosystems are at the interface between land and sea and thus receive nutrients from both land/seascapes. The seasonal nesting of sea turtles introduces large inputs of eggs, and so nutrients, onto sandy beach ecosystems, but little is known about the effects of these spatially and temporally variable nutrient input pulses on the dynamics of consumers in the recipient system. In this study, I examined the ecological role of sea turtles as vectors of nutrients that introduce large amounts of nutrients (in the form of eggs) from distant foraging grounds into nutrient-poor beach ecosystems. Although some of the nutrients return to the sea in the form of hatchlings, nutrients from unhatched and depredated eggs, dead and predated hatchlings, as well as chorioallantoic fluid and egg shells remain on the beach and presumably enter sandy beach food webs. I hypothesized that turtle nutrients significantly increase the availability of nutrients to sandy beach ecosystems and that those nutrients are incorporated by both terrestrial and marine food webs. These hypotheses were tested by comparing isotopic signatures of 13C and 15N of consumers on beaches with high and low turtle nest densities. The response of meiofauna to the decomposition of turtle eggs was also investigated. I predicted that meiofaunal abundance is positively affected by turtle nutrients and that higher meiofaunal abundances will be obtained in decomposing, depredated nests. I tested this hypothesis by comparing meiofaunal abundance in naturally predated nests to densities away from turtle nests (as a control). An in situ experiment that mimics conditions of naturally predated sea turtle nest, was set up to test meiofaunal community responses to turtle nutrients over time. The study indicates that sea turtle eggs represent a short pulsed resource subsidy that increases the nutrient and energy budget of sandy beach ecosystems. The results show that of the five potential nutrient pathways tested, ghost crabs appear to consume egg nutrients in measurable quantities, altering their diet and feeding behaviour according to food availability. The study also showed that there was a strong, but short-lived positive response of meiofauna to the introduction of nutrients, with increased abundance of all taxa in predated nests and experimental treatments. This response was particularly strong for nematodes which peaked in abundance after seven days. I conclude that turtle-derived nutrients represent a pulsed resource subsidy that makes significant contribution to the energy budget of sandy beach/dune ecosystems.

In the first part of this thesis definitions of sea level are given and causes and effects of its seasonal and secular variations are briefly discussed. The second part deals with the numerical determination of these changes on the coast of British Columbia. Using raw tidal data in the form of monthly means of sea level, seasonal variations are determined as annual oscillations with mean amplitudes between 5 and 12 cm for seven stations on the B.C. coast. The investigation of secular variations is based on (raw) annual means of sea level. These variations are essentially represented by linear trends which are statistically significant at the stations VICTORIA, VANCOUVER, POINT ATKINSON and PRINCE RUPERT, where they indicate submergence. Assuming an eustatic rise of sea level at the rate of 1.0 mm/yr, the influence of land movement on submergence is estimated. For VICTORIA, a probable land uplift since 1909 and for VANCOUVER, POINT ATKINSON and PRINCE RUPERT a definite land subsidence since about 1943 is found. The rates of land subsidence range between 1 and 2 mm/yr. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

A detailed palynological examination was made of Tertiary pollen and spore assemblages from six exploratory wells located along the continental margins of the Labrador Sea. From north to south, the study wells are Kangamiut 1, Hekja 0-71, Karlsefni A-13, Herjolf M-92, Roberval K-92 and Cartier D-70. Using local extinction events of zonally diagnostic species to define the tops of intervals, eight provisional pollen and spore zones were established. The zones and their relative ages are as follows: Tsuga igniculus (middle to late Miocene); Fagus granulata (early to middle Miocene); Parviprojectus sp. A (early Oligocene); Araliaceoipollenites megaporifer (latest Eocene/earliest Oligocene); Rhoipites latus (middle to late Eocene); Pistillipollenites mcgregorii (early to middle Eocene); Tricolpites sp. A (middle to late Paleocene); and Paraalnipollenites alterniporus (early to middle Paleocene). The middle and upper Oligocene is apparently absent in the study welIs. When used in conjunction with dinoflagellate assemblages, the zonation provides the potential for additional biostratigraphic resolution in the Tertiary marine sediments of the Labrador Sea. It is especially useful in upper Eocene and stratigraphically higher sections in which pollen and spores are the dominant component of the palynoflora: In addition, the basic similarity of pollen and spore assemblages across much of northern and western Canada suggests the zonation may also be successfully applied in those regions. The relative abundance and distribution of four major populations (i.e., Paleozoic, Upper Jurassic/Lower Cretaceous, Upper Cretaceous and Paleogene) of redeposited palynomorphs were determined. The species composition of recycled and in-situ Paleogene palynomorphs supports independent clay mineralogical data that much of the sediment (including a high percentage of the palynomorphs) was delivered to offshore Labrador Sea basins via a "super" river system that drained a large portion of the western interior and Arctic regions of Canada during the Tertiary. The taxonomic composition of the indigenous Paleogene pollen and spore flora supports both paleontological and isotope data that relatively high paleotemperatures prevailed at high northern latitudes during the Paleogene. The climatic optimum in the Labrador Sea region was reached in the early to early-middle Eocene. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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