Thesis working title:

Canadian Shield Lakes of Eastern Ontario: A paleolimnological study to reveal water quality changing trend over the past ~150 years under the synergistic impact of climate & land-use change

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Eastern Ontario is a lake-rich region, whose economy largely depends on lake-based tourism and recreational activities and therefore on lakes’ water quality. Total Phosphorus (TP) loading, associated with land-uses, and climate warming are known to negatively affect water quality by promoting algal blooms. The lakes are mainly located in the Canadian Shield region, mostly covered forest, distinct wetlands. Hence, the lakes are typically clear, fairly nutrient-poor (TP < 20 µgm L-1) and non-acidic (pH >7) in nature. Yet there is a growing concern about increasing harmful and nuisance algal blooms. The impact of nutrient enrichment along with climate change may be promoting algal blooms in this region, but this combined impact is not well understood. I am interested to fill up the knowledge gaps about the combined impact of land-use and climate change. Moreover, few lakes of this region are highly eutrophic, and the reference states of the lakes are still unknown because of the scarcity of long-term water monitoring data. I am using the paleolimnological technique using the fossil diatom stored in lake sediments to infer baseline TP concentration and water quality trend over the past ~150 years of the Canadian Shield lakes.