Detecting hydrological and carbon-cycle change in high-latitude environments with compound-specific isotope analyses

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Arctic and Subarctic regions of the Earth are warming faster than the rest of the planet, and this climate change will probably strongly affect water resources in these regions, as well as the amount of natural carbon greenhouse gas emissions (e.g. carbon dioxide and methane) they produce. However, the effects of climate change on water and carbon cycling in Arctic regions are not well understood. The proposed research will seek to gain a better understanding of these aspects of Arctic environmental change, both by studying how Arctic environments changed during past periods with warm climates, and by gathering detailed information about how water and carbon move through Arctic environments today. This research is performed by analyzing the natural abundance of rare isotopes, or atoms with slightly heavier-than-normal masses, in individual organic molecules found in lake sediments. When water or carbon moves between different environments the abundance of their isotopes changes, and because of this, isotope measurements can provide a record of environmental change. This research will focus on analyzing isotope ratios in individual organic molecules produced by different organisms, a novel approach that will avoid uncertainties associated with other isotope analyses. Specific questions this research will help address include: 1) How did rainfall and lake levels change in Northeastern Canada when temperatures became warmer or cooler; 2) What happens to carbon when it moves from soils to lakes, and can it be stored in lake sediments for long periods of time; 3) What controls how much methane is produced in lakes, and how much of that methane escapes to the atmosphere.******This research is important because it will provide new data on how Arctic ecosystems responded to climate change in the past, and will help to predict how these ecosystems could change in the future. This is necessary for climate scientists and policymakers who need to understand how different parts of the world will respond to global warming. This research is also important to Canadians who live in northern regions, since it can help to explain the dramatic changes that are occurring in their home. This research will benefit Canadians by giving a clearer picture of both the future of water resources in northern regions and the risk that northern environments will begin to emit more greenhouse gases as the climate warms.*****