Collaborative Research: Quantification of Dominant Heat Fluxes in Streams and Rivers in Arctic Alaska

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Understanding the impacts of climate change on freshwater ecosystems is highly dependent on quantifying the associated changes in instream temperatures. However, this can be complicated because these temperatures are related to both changing meteorology (e.g., air temperature and precipitation) and hydrology (e.g., instream flows and lateral inflows). The ability to predict climate related changes on instream thermal regimes in Arctic streams is limited by the minimal understanding of key processes and the availability of data to quantify heat fluxes. The investigators hypothesize that the dominant heat fluxes within Arctic streams are similar to those in temperate climates but that the relative magnitude of the heat fluxes differ, and that quantification of lateral inflows is key in predicting water temperatures. To test this hypothesis, they would address three research questions regarding 1) the changing importance of key heat fluxes throughout the warm season; 2) the importance of lateral inflows to understanding instream temperature regimes; and 3) the sensitivity of instream temperatures to climate change drivers. To answer the first two questions, they would: quantify heat fluxes using data collection and modeling efforts in two representative arctic river types (alluvial and peat lined, beaded) near Toolik Lake, Alaska; adapt instream temperature models based on prior temperate zone hydrologic research to determine which heat fluxes are necessary to predict the spatial and temporal variability of Arctic instream temperatures; and use differential gauging at the reach and basin scales, along with distributed instream temperatures and other measures, to quantify hillslope-stream connectivity and lateral inflows. Given these results, they would address question 3 by conducting sensitivity analyses of anticipated climatic variability to identify the key hydrologic and meteorological drivers of instream temperature regimes. Ultimately, they would develop an Arctic-specific temperature model that provides predictive capabilities of instream temperatures. In the course of this research, the investigators would develop related curriculum exercises in close collaboration with high school science teachers in both Utah and Alaska, and subsequently make these available nationally. Graduate and undergraduate students would participate in the field and analytical work, and the investigators would share their results with local communities in Alaska who depend on aquatic resources for food.