TO MODEL OR TO MEASURE: THE CHALLENGES OF CONSTRAINING GAS EVASION ESTIMATES FOR ACCURATE ESTIMATION OF WHOLE-STREAM METABOLISM
Whole ecosystem productivity and respiration can be modeled in streams using diel changes in dissolved O2 concentration. Stream metabolism models rely on accurate measurement or modeling of a gas exchange rate coefficient (K d-1) to allocate changes in dissolved O2 concentration to physical reaeration or ecosystem respiration. Empirical measurements of K are time consuming and require many repetitions to construct a rating curve over a range of stream discharge (Q). Various modeling approaches to estimate K have different degrees of prediction accuracy, which may be improved upon by including empirical estimates of K to constrain model estimates. The accuracy or the strength of the K vs Q relationship can drive the outcome of the modeled ecosystem metabolism. High slope and low productivity streams produce modeled metabolism estimates with lower confidence due to the increased role of gas exchange in temporal changes in dissolved O2 concentration. The comparison between modeling and empirical measurements of K across several types of stream ecosystems indicate that constraining the K-Q relationship is an important step in estimating ecosystem metabolism.
Alice Carter (Primary Presenter/Author), Duke University, email@example.com;
Amber Ulseth (Co-Presenter/Co-Author), Ecole Polytechnique Fédérale de Lausanne, firstname.lastname@example.org;
Lauren Koenig (Co-Presenter/Co-Author), University of Connecticut, Lauren.Koenig@uconn.edu;
Jim Heffernan (Co-Presenter/Co-Author), Duke University, email@example.com;
Emily Bernhardt (Co-Presenter/Co-Author), Duke University, firstname.lastname@example.org;