Estimation and quantification of surface water metabolism dynamics on monthly basis: A case study of ardahan

Recently, river metabolism has become an important subject since it reflects the structural and functional properties of rivers. In this thesis study, the values of gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) were estimated at five locations along one of the branches of river Kura using "single-station method" depending on different atmospheric exchange coefficients (K). For the first time in Turkey, river metabolism components were quantified for a river using the single-station method. At five monitoring locations determined in the thesis study between May and December 2018, the measurements of dissolved oxygen concentration, and water temperature were performed every five minutes for at least two days per month. Based on the monitoring data obtained, the estimation of GPP, ER, and NEP was conducted with six methods. River metabolism components were computed using Rivermet© program. dissolved oxygen concentration, and water temperature were measured using MiniDOT probe. River flow rate and depth were measured using Son Tek Flow Tracker Handheld ADV. GPP, ER and NEP estimates varied spatially and temporally. Also, the coefficient of K was shown to play a rather important role in the quantification of the metabolic components. River flow rate, depth and velocity significantly influenced the K coefficient, thus directly affecting the quantification of river metabolic components. Thus, the determination of the K coefficient with a proper method is of critical importance to river metabolism studies. From spring to mouth of the river, the GPP value markedly rose. This case was attributed to the change in water quality and quantity. The study showed that the river was net heterotrophic (GPP/ER < 1).