| Summary: | Dissolved organic matter (DOM) is a ubiquitous component of aquatic and terrestrial systems and an important constituent that can influence aquatic health and drinking water quality. For instance, DOM can act as an important nutrient for microbes or react with chlorine during treatment of drinking water supplies to form harmful disinfection by-products. As DOM is comprised of thousands of different organic molecules, the degree that DOM reacts with its surroundings depends not only on the amount of carbon, but also on its composition. A changing climate can influence DOM concentration and composition in a number of ways, such as by altering the residence time within the watershed or changing rates of DOM processing through warming temperatures. Recently, changes to DOM quality and quantity have been observed across surface waters in the northern hemisphere, which can complicate future drinking water treatment options. Organic-rich areas underlain with permafrost are found across the circumpolar north, leading to uncertainty over the effects of permafrost degradation on carbon release and fate, particularly upon downstream ecosystems and drinking water resources. Better prediction as to how DOM will respond under a warming climate requires an understanding of the variability in the amount and composition of DOM, as well as the drivers of DOM reactivity. However, the few arctic or sub-arctic locations with comprehensive DOM datasets can be difficult to compare due to the use of various DOM characterization techniques. Further, data are lacking, or entirely missing, in many areas of Canada’s western sub-arctic. The overall goal of this thesis is to use field and laboratory measurements to quantify the heterogeneity encountered in DOM concentration and composition from a variety of hydrologic environments in three Canadian sub-arctic and arctic ecoregions, and to link this variability to DOM lability. Statistical analyses of long-term monitoring of river hydrology and water quality provides a quantitative measure to ...
|
|---|