Latent and sensible heat fluxes at the surface of Baffin Bay are calculated throughout the year using, in addition to the essential meteorological data and surface temperatures, values of the ice cover corresponding to three different periods of years, ranging from 1919 to 1965. [...]

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A simple linear reduced-gravity ocean model is developed to simulate the North Water polynya located in northern Baffin Bay. The model is an extension of Pease (1987) latent-heat model for a coastal polynya. Both northerly surface wind forcing and coastal upwelling processes are taken into account in modelling the steady state and time-dependent water velocities, upper layer depth, and polynya width measured southward from its northern boundary. Also, both uniform and variable wind forcing are considered. In most of this thesis a semi-infinite domain model is used in which upwelling occurs along the eastern boundary (the Greenland coast). It is found that the steady state polynya width is a strong function of the air temperature, but a weak function of the wind speed. The model results show that in the upwelling region near the Greenland coast, the polynya width is larger than further offshore (distance $>$ 2 Rossby radii), where it is a constant (the limiting Pease width). For a variable wind forcing, the southern ice edge of the North Water has a form that is similar to that of the wind forcing. In a channel, upwelling occurs in the eastern part and downwelling in the western part. Thus the polynya is much wider near Greenland and narrower near the Canadian Islands.

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It has been estimated that approximately half of all anthropogenic fossil fuel carbon dioxide (CO2) emissions have been absorbed by the oceans. Air-sea gas exchange of CO2 and the buffering capacity of seawater allows the oceans to store significant amounts of dissolved inorganic carbon (DIC; ~38,000 GtC). The Arctic Ocean is currently warming at double the rate of the rest of the planet, yet the effect of climate change on the Arctic marine carbon cycle remains unconstrained. Recent work suggests that Arctic marine environments are a carbon sink for the majority of the year, and plays a key role in storing anthropogenic carbon below the mixed layer. Baffin Bay is a semi-enclosed, Arctic basin that supplies cold surface water to the Labrador Sea; a critical region for North Atlantic deep-water formation. While the physical oceanography of surface Baffin Bay is well characterized, less is known about deep water formation mechanisms and its ventilation age. The few residence times for Baffin Bay Deep Water (BBDW) range widely from 20-1450 years. Improved residence time estimates are essential for understanding the role Baffin Bay plays in the Arctic carbon cycle and how this region will respond to climate change. Radiocarbon (D14C) and stable carbon (δ13C) measurements of DIC are powerful tools for parameterizing water mass sources, aging and residence times. However, very few DIC Δ14C and d13C data have been reported in the Arctic Ocean, comprising only a handful of stations in the Eurasian Basin, Canadian Basin, and Beaufort Sea. With this goal in mind, we conducted a study in which DIC samples were collected aboard the CCGS Amundsen in 2019 for δ13C and Δ14C analysis. DIC δ13C and D14C values ranged from 0.68‰ to +1.90‰ and -90.0‰ to +29.8‰, respectively. Surface DIC δ13C values were +0.69‰ to +1.90‰, while deep (>100m) d13C values ranged -0.01 to -0.68‰. Significant linear correlations were found for δ13C and potential density, suggesting DIC δ13C is an effective water mass and carbon source tracer in Baffin Bay. Surface DIC Δ14C values ranged -5.4‰ to +22.9‰, while deep DIC (>1400m) DIC Δ14C averaged -82.2 8.5‰ (n = 9). Much larger surface to deep gradients in DIC Δ14C are observed in Baffin Bay vs. that of the North Atlantic Ocean, suggesting significant aging of BBDW. Next, we used the potential alkalinity method (Palk) and the ΔC* method to quantify the amount of “bomb” 14C and anthropogenic C (DICanth) to model “natural” DIC Δ14C profiles. Both Palk and ΔC* proxies had high errors in cold, low salinity surface water. In particular, surface (<400m) Δ14Cbomb was overestimated at all stations. However, both proxies did not indicate Δ14Cbomb or DICanth contributions below 1000m. Two 14C residence times were estimated based on two proposed mechanisms of BBDW formation. A residence time of 690 +/- 35 years was estimated assuming surface brine rejection in Nares Strait is the main source of BBDW. Another plausible source of BBDW is the entrainment of dense north Atlantic Water over Davis Strait mixed with brine enriched surface water. A comparison of DICanth and Δ14Cbomb corrected deep DIC Δ14C values from the North Atlantic (GO SHIP A16N) to BBDW, resulted in a residence time of 360 +/- 35 years. These residence times (360-690 years) provide new constraints on the ventilation age of deep Baffin Bay and suggest this basin has the potential to store carbon for centuries.

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The recent discovery of the 31-km-wide Hiawatha impact crater has raised unanswered questions about its age, impactor and highly unusual organic carbon component. Previous research suggests a fractionated iron meteorite impactor, a probable maximum 3–2.4 Ma impact age and a possible Younger Dryas impact age. The first objective in this study has been to investigate a possible link between the Cape York meteorites and the Hiawatha impact crater by comparing the chromium isotopic signature in chromite from a Cape York meteorite with the chromium isotopic signature in potential chromite from the Hiawatha impactor. The second objective has been to investigate a possible Hiawatha signature in the Younger Dryas deposits from Baffin Bay. The third objective has been to study the organic carbon component in impactites derived from the Hiawatha impact crater. Heavy mineral grains were separated from glaciofluvial sediment which contains Hiawatha impactite grains. Not a single chromite grain was found and the possible link to the Cape York meteorites could not be tested. The petrographic examination of Younger Dryas marine deposits resulted in absence of impact-related Hiawatha grains. A petrological investigation revealed that organic carbon was likely found in five of six variably shocked impactites derived from the Hiawatha impact crater. The character of the organic carbon varies between the samples and also within individual samples. Vitrinite reflectance measurements of the organic carbon in two impactites yielded low reflectance values compared to charcoalification experiments of wood. Organic particles with different reflectance in the same sample suggest that the particles had different impact histories prior to settling and becoming a rock. Diagnostic conifer cellular texture was found in at least one of the samples. The character of the organic particles in the impactites supports the suggestion in a previous study that the sources of the Hiawatha organic carbon component are unmetamorphosed surficial deposits containing dead conifer tree trunks and fine-grained layered clay and organic matter.  In this study it is concluded that the apparent absence of chromite in the examined glaciofluvial sediment sample corroborates the significance of previous research which suggests that the Hiawatha impactor was an iron meteorite. The apparent absence of impact related grains in the Younger Dryas deposits suggests that although a Younger Dryas age for the Hiawatha impact crater is less likely now, the possibility remains open. The organic carbon with diagnostic conifer cellular texture in the Hiawatha impactites corroborates the conclusion in a previous study that the Hiawatha impact-related organic carbon component stems from local, thermally degraded conifer trees with a probable age of ca. 3–2.4 Ma. It is also concluded that the relatively low reflectance values of the organic carbon in the Hiawatha impactites seem to be related to the short duration of the high-temperature excursion during the hypervelocity impact event.