FTIR spectrochemical imaging analysis of lipid and protein content of bottom-ice diatoms along a tidal strait within the Kitikmeot Sea, Canadian Arctic

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Pogorzelec, Nicole
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Within the ice bottom, ice algae begin their annual Arctic spring bloom in which they contribute up to half of the total annual primary production in the central Arctic Ocean. Essential fats (or lipids) are produced during the early portion of the ice algal bloom (e.g., polyunsaturated fatty acids (PUFAs) such as omega-3 fatty acids) and are of particular importance to the energy-rich Arctic marine ecosystem. Fourier Transform Infrared (FTIR) Spectrochemical imaging is an efficient and non-destructive analytical technique, which allows us to measure changes in ice algal biomolecular composition (i.e. saturated lipid, protein and biogenic silica). In this thesis, we examine diatom samples collected from first-year landfast sea ice across a tidal strait region located between the Finlayson Islands within Dease Strait of the Kitikmeot Sea, near Cambridge Bay, Nunavut, Canada. This research was conducted under the ICE-CAMPS (Ice Covered Ecosystem-Cambridge Bay Process Study) 2017 spring field campaign. It was determined, via two case studies: i. the relative amount of biomolecular composition was a function of cell size and species. ii. individual cell biomolecular composition trends were not depicted in bulk measurements (i.e. particulate organic carbon, chlorophyll a, etc.) iii. Two expected nutrient gradients were observed within the tidal strait region, one spatially and one vertically iv. lipid (protein) content increased (decreased) spatially in response to nutrient limitation, while lipid (protein) content increased (remained constant) vertically in the sea-ice v. the creation of new FTIR imaging methods were successful in rapidly imaging the diatom community. The findings presented here have reinforced the usefulness of the FTIR instrument to diatom autecological analysis. This sensitive, non-destructive and semi-quantitative analytical technique has allowed us to further our understanding not only of the ice algal community, but also the autecology of individual diatom taxa.
FTIR, Diatom, Attheya spp., Nitzschia frigida, Protein, Lipid, Bimolecular Composition, Biomass, Arctic, Tidal Strait