Large differences in soil accumulation between watersheds < 10km apart (Wood River system, SW Alaska).
Photo credit: Jason Ching
Freshwater systems and the ecosystem services they provide to humans are fundamentally connected to what happens within their watersheds. In my dissertation I focused on understanding how broad scale watershed features influence the movement of materials and energy between aquatic and terrestrial environments. I worked primarily in a pristine boreal Alaskan river system, where a high level of physical heterogeneity, coupled with natural landscape gradients, reveal underlying controls on ecosystem processes.
Using stable and radioisotopes and fatty acid tracers, I found that mean watershed slope affects assimilation of terrestrial versus within-stream resources by stream consumers such as aquatic insects. Further, watershed slope, by determining the degree of soil carbon accumulation within watersheds and the strength of stream-riparian hydrologic connections, influences both the magnitude and source of CO2 emissions from streams. These patterns provide a way to extrapolate across boreal landscapes and predict how carbon cycling and food webs will respond to continued climate warming.
Adrianne P. Smits, D. E. Schindler, G. W. Holtgrieve, K. Jankowski, and D. French. 2017. Watershed geomorphology interacts with precipitation to influence the magnitude and source of CO2 emissions from Alaskan streams. Journal of Geophysical Research: Biogeosciences 122, doi:10.1002/2017JG003792.
Daniel E. Schindler and Adrianne P. Smits. 2016. Subsidies of aquatic resources in terrestrial ecosystems. Ecosystems. doi:10.1007/s10021-016-0050-7
Adrianne P. Smits, Daniel E. Schindler, and Michael T. Brett. 2015. Geomorphology controls the trophic base of stream food webs in a boreal watershed. Ecology 96: 1775-1782.