Turkey Lakes Watershed Study reference list: 2016

16-01 Caputo, J., C.M. Beier, P.M. Groffman, D.A. Burns, F.D. Beall, P.W. Hazlett and T.E. Yorks. Effects of harvesting forest biomass on water and climate regulation services: a synthesis of long-term ecosystem experiments in eastern North America. Ecosystems 19: 271-283, doi: 10.1007/s10021-015-9928-z, 2016.

Summary: New methods assessing trade-offs between biomass harvestings and ecosystem services and their change over time were applied to long- term experimental post-harvest data from the TLW and nine other northern hardwood forest watersheds. Near-term trade-offs were observed between biomass harvesting and the ecosystem services of nutrition pollution remediation and greenhouse gas regulation.  Both these ecosystem services recovered with forest vegetation regeneration. Biomass harvesting had relatively nominal and transient impacts on other ecosystem services.

16-02 Enanga, E. M., I. F. Creed, N. J. Casson, and F. D. Beall. Summer storms trigger soil N₂O efflux episodes in forested catchments, Journal of Geophysical Research: Biogeosciences 121, 95-108, doi:10.1002/ 2015JG003027, 2016.

Summary: Soil physical and chemical properties and N₂O and N₂ efflux were measured in catchment 38 at the TLW from 2005 to 2010. Hotspots and hot moments of soil N₂O and N₂ efflux were observed in topographic positions that accumulate precipitation. A consequence of the higher frequency of extreme precipitation events predicted under climate change scenarios is the shift from an aquatic to atmospheric fate for N, resulting in a significant forest N efflux. This in turn creates feedbacks for even warmer conditions due to increased effluxes of potent greenhouse gases.

16-03 Beck, K.K., A.S. Medeiros and S.A. Finkelstein. 2016. Drivers of Change in a 7300-Year Holocene Diatom Record from the Hemi-Boreal Region of Ontario, Canada. PLoS ONE 11(8): e0159937. doi:10.1371/journal.pone.0159937

Summary: Potential drivers of long-term change in diatom assemblages at Wishart Lake were evaluated using a Holocene lake sediment record spanning the past 7300 years. Results illustrate the close connection between paleoclimate change, regional vegetation, watershed processes, and diatom assemblages and provides insight into the controls on abundance of Cyclotella sensu lato, a diatom taxonomic group which has shown significant increases and complex dynamics in the post-industrial era in lakes spanning temperate to Arctic regions. 

16-04 Brush, J. M., K.E. Smokorowski, J. Marty and M. Power. 2016. Fish feeding niche characterization over space and time in a natural boreal river. Ecohydrology 9: 1400-1409

Summary: Using a 10-year dataset from Batchawana River, temporal variability of fish feeding niche in response to variable flows and temperature or temporal consistency of spatial differences in fish feeding niche within a natural river were examined. The fish feeding niche was temporally invariant in the lower sampled river reaches, but increased over time in the upper reaches. Fish feeding niche was significantly larger in the lower than upper Batchawana River, but there were no significant differences in mean fish community between reaches. Results highlight that in natural undisturbed rivers, fish feeding niche appears to be temporally invariant in the face of naturally imposed environmental variability. 

16-05 Crossman, J., M.C. Eimers, N.J. Casson, D.A. Burns, J.L. Campbell, G.E. Likens, M.J. Mitchell, S.J. Nelson, J.B. Shanley, S.A. Watmough and K.L. Webster. 2016. Regional meteorological drivers and long term trends of winter-spring nitrate dynamics across watersheds in northeastern North America. Biogeochemistry doi: 10.1007/s10533-016-0255-z

Summary: A 20-year period (1990/91-2009/10) in nine study sites across Canada and the U.S., including 2 catchments in the TLW, were selected for analysis to evaluate the contribution of winter rain-on-snow (ROS) events to annual and seasonal nitrate (N-NO₃) export and identified the regional meteorological drivers of inter-annual variability in ROS N-NO₃ export (ROS-N). ROS events contributed a significant proportion of annual and winter N-NO₃ export at the majority of sites. In years with a greater magnitude of ROS events, timing of the peak N-NO₃ export period (during spring melt) was redistributed to earlier in the year. Snowpack coverage was particularly important for explaining the site-specific ROS response. Results suggest catchment response to changes in N deposition is sensitive to climate change; a vulnerability which appears to vary in intensity throughout the seasonally snow-covered temperate region. Also, downstream nutrient stoichiometry and the community composition of phytoplankton and other algae are affected by sensitivity of stream N-NO₃ export to ROS events and potential earlier timing of N-NO₃ export relative to other nutrients.

16-06 Enanga, E.M., I.F. Creed, T. Fairweather and N.J. Casson. 2016. Snow covered soils produce N₂O that is lost from forested catchments prior to snowmelt. Journal of Geophysical Research – Biogeosciences doi: 10.1002/2016JG003411

Summary: The magnitude of net soil nitrous oxide (N₂O) production from a snow-covered catchment (C38 in TLW) was investigated. Topographic position was found not to affect net N₂O production despite significant variation in soil moisture, reduction-oxidation condition, and pore water dissolved organic carbon and nitrate. Soil temperatures did not vary among the topographic positions, suggesting temperatures at or above freezing point allow N₂O production to proceed under the snowpack. Redox conditions were lower at wetland positions compared to lowlands and uplands, suggesting biogeochemical pathway of N₂O production varies with topography. 31% of the growing season N₂O-N production was exported to the atmosphere over the entire nongrowing season. Results suggest that winter is an active time for gaseous N production in these forests and N₂O production under the snowpack represents an often unmonitored flux of N from catchments.

16-07 Lecki, N.A. and I.F. Creed. 2016. Forest soil CO2 efflux models improved by incorporating topographic controls on carbon content and sorption capacity of soils. Biogeochemistry doi: 10.1007/s10533-016-0233-5

Summary: This study looks at improving modeling techniques to predict the fate of carbon in forest soils under changing environmental conditions. Soil CO₂ efflux was measured along varying topography in a catchment in TLW within a temperate sugar maple forest. When soil carbon content and sorption capacity were added to the models, the amount of explanation increased slightly on a gentle hillslope, and substantially on a steep hillslope. Carbon content in organic-rich surface of the mineral soil was positively related and sorption capacity was negatively related to soil CO₂ efflux rates. More accurate estimates of forest soil CO₂ efflux must take into account topographic influences on the carbon pools, the environmental factors that affect rates of carbon transformation, and the physiochemical factors that determine the fraction of the carbon pool that can be transformed.

16-08 Mengistu, S.G., A.A. Melkamu and F.A. Yassin. 2016. Assessment of the Sensitivity of Streamflow Simulations to Changes in Patch Resolution Using GIS Based Hydro-Ecologic Model. Open Journal of Modern Hydrology doi: 10.4236/ojmh.2016.62007

Summary: This study investigates the impact of patch characterization on simulated flow regime, and on the calibration of the Regional Hydro-Ecologic Simulation Systems’ (RHESSys) main hydrological parameters: saturated hydraulic conductivity, k, and decay of saturated hydraulic conductivity with depth, m. Eight different patch configurations of a subcatchment of the TLW were used. The best simulation results were obtained for the patch configuration with the highest spatial variation of climate, stream network and hillslope conditions across the subcatchment. But, there are implications for the physical interpretation and transferability of the calibrated parameter values for different patch configurations.

16-09 Zhu, R., A.H. El-Shaarawi, X. Duan, Z. Wang and R. Ma. 2016. Assessing annual trends, monthly fluctuations and between-station relationship of sulphate deposition in the Turkey Lakes Watershed. Environmetrics doi: 10.1002/env.2388

Summary: Air and water quality was assessed by studying sulphate deposition change over time from multiple monitoring stations in the TLW. A temporally correlated multivariate random effects into Gamma regression model was incorporated to account for the temporal dependence within and between-station dependence in space. This approach was used to analyse monthly average sulphate depositions between 1983 and 2003. Results showed that annual trends in sulphate deposition had stabilized between 1994 and 2003, and sulphate deposition increased from upstream to downstream with monthly fluctuations higher in winter to lower in summer.