LONG-TERM OPEN WATER METABOLISM ESTIMATES ASSOCIATED WITH SEDIMENT RESTORATION IN A LOW-GRADIENT RIVER
Anthropogenic disturbances including mining and logging can alter benthic substrate in rivers thereby altering microbial communities and ecosystem metabolism. We examined how river metabolism varied daily, annually, and in response to a 30m reach sediment restoration of a sand-dominated section of the Salmon Trout River, Marquette, MI. Temperature and dissolved oxygen concentrations were measured from May-November of 2010-2014, and sand removal occurred in June 2013. Initial modeling of open water metabolism used nighttime regression, for reaeration calculations, and diurnal oxygen saturation changes. The model demonstrated variable rates with gross primary production (GPP) ranging from 0 to 12 gO2/m2/d and ecosystem respiration (ER) ranging from -1 to -19 gO2/m2/d. The river was consistently net heterotrophic, with annual mean GPP ranging 2 to 4 gO2/m2/d and ER ranging -5 to -9 gO2/m2/d. These rates were similar to those reported in the literature for rivers not degraded by fine sediment. We are revising these estimates using Bayesian inverse modeling and exploring temporal patterns in metabolism rates relative to the sediment restoration and both daily and inter-annual variation in climate and other environmental drivers.
Kevin Nevorski (Primary Presenter/Author), Michigan Technological University, firstname.lastname@example.org;
Amy Marcarelli ( Co-Presenter/Co-Author), Michigan Technological University, email@example.com;
Sue Eggert ( Co-Presenter/Co-Author), USDA Forest Service, Northern Research Station, firstname.lastname@example.org;
Casey Huckins ( Co-Presenter/Co-Author), Michigan Technological University, email@example.com;