Turkey Lakes Watershed Study reference list: 2014

14-01 Mengistu, S.G., I.F. Creed, K.L. Webster, E. Enanga and F.D. Beall. Searching for similarity in topographic controls on carbon, nitrogen and phosphorus export from forested headwater catchments. Hydrological Processes 28 (8), 3201-3216, doi: 10.1002/hyp.9862, 2014.

Summary: Topography influences the hydrological processes that in turn affect biogeochemical export to surface water on forested landscapes. Annual dissolved organic carbon (DOC) and nitrogen (DON), inorganic nitrogen (NO₃^--N) and phosphorus (total dissolved phosphorus, TDP) exports were measured in catchments of the TLW. Topographic indicators 1) hydrological storage potential and 2) hydrological flushing potential were designed in order to represent hydrological processes which influence nutrient export. Much of the variation in nutrient export among catchments was found to be attributable to topographic factors, although to differing degrees among nutrients. This study finds that topographic indicators are an effective tool to track biogeochemical exports to surface water from catchments on forest landscapes.

14-02 Webster, K.L., I.F. Creed, T. Malakoff and K. Delaney.  Potential vulnerability of deep carbon deposits of forested swamps to drought. Soil Science Society of America Journal 78 (3), 1097-1107, doi:10.2136/sssaj2013.10.0436, 2014.

Summary: Summer droughts are occurring with greater regularity and intensity due to climate warming. These changes raise concerns for the decomposition of C stores found beneath the water table in saturated peat. Saturated peat cores from the TLW underwent artificial drying and were monitored for daily CO₂ production and for potential drivers of CO₂ production (peat quality, microbial biomass, and enzyme activity) in order to measure the effect of dessication on CO₂ production. CO₂ production was found to be highest in the top 30cm of the peat profile, at intermediate volumetric water contents. The low quality (high C/N) of peat in the catotelm limits rapid release of CO₂ with water table declines.

14-03 Creed, I. F., A.T. Spargo, J.A.  Jones, J.M. Buttle, M.B. Adams, F.D. Beall, E.G. Booth, J.L. Campbell, D. Clow, K. Elder, M.B. Green, N.B. Grimm, C. Miniat, P. Ramlal, A. Saha, S. Sebestyen, D. Spittlehouse, S. Sterling, M.W. Williams, R. Winkler and H. Yao. Changing forest water yields in response to climate warming: results from long-term experimental watershed sites across North America. Global Change Biology 20(10), 3191-3208, doi: 10.1111/gcb.12615, 2014.

Summary: Climate warming is projected to affect forest water yields but effects are expected to vary. Investigation of how forest type and age affect water yield resilience to climate warming was completed using variability in historical water yields over 5-year cool and warm periods at catchments, including the TLW, across Canada and the United States. Alpine sites showed greatest sensitivity to climate warming. Forest type appeared to influence the resilience of catchment water yields to climate warming, with conifer and deciduous catchments being more susceptible to climate warming than the more diverse mixed forest catchments.

14-04 Egginton, P., F. Beall and J. Buttle. Reforestation-climate change and water resource implications. The Forestry Chronicle 90 (4), 516-524, 2014.

Summary: n a forested catchment, river discharge can be decreased or augmented by forest management practices such as appropriate species selection, density management and length of rotation. With the growing awareness of climate change and its impacts, the adequacy of our water supply is becoming an issue. At the same time there is greater discussion about using our forests for carbon sequestration and biofuels. This paper outlines implications for annual and seasonal river flows after widespread reforestation and concludes that informed choices need to be made as to the overall objectives of forest management. Research at the TLW provided background knowledge that contributed to the concepts presented in this paper.

14-05 Enanga, E.M.  Topographic controls on N₂O and N₂ efflux in a temperate forest.  PhD. Thesis, Department of Biology, University of Western Ontario, London.  123pp,  Appendix, 2014.

Summary: Topographic influences on soil temperature, moisture, reduction-oxidation (redox) potential, dissolved organic carbon, and nitrate conditions, which in turn influence N₂O release, were investigated at the TLW. More N₂O was released during the summer from the inner (IW) and outer (OW) wetland positions than from lowland and upland topographic positions. Significant positive relationships between N₂O efflux and precipitation events in both the IW and OW were observed. Substantial biogeochemical activities were observed during the non-growing season under a snow-pack, including denitrification. Adding N₂ and N₂O fluxes to catchment N export not only reduced the discrepancy in N export observed among catchments but also between N inputs and outputs.