This dataset contains field measurements, laboratory analyses, lakemetab model code, and model outputs from an Oligotrophic Lake in Franklin, Tennessee, collected as part of PhD research on diel and seasonal variations in lake ecosystem. The primary component of this dataset is a modified implementation of the LakeMetabolizer model, adapted to estimate lake metabolism parameters using the ordinary least squares (OLS) approach. This customized workflow was designed to generate instantaneous rather than daily mean estimates, allowing for higher-resolution characterization of diel metabolic fluctuations across seasonal light and temperature regimes. In addition to the metabolism modeling framework, the dataset includes a custom R script for generating three-dimensional (3D) depth profiles of dissolved oxygen and PAR values. This visualization tool provides spatial context for diel oxygen dynamics by illustrating vertical and temporal variability within the lake’s water column. Supporting data include high-frequency time-series measurements of dissolved oxygen, temperature, and pH collected during seasonal diel campaigns. Together, these datasets and analytical tools contribute to understanding diel and seasonal biogeochemical and metabolic variations in oligotrophic freshwater systems while providing a reproducible and FAIR-compliant framework for open lake metabolism research. Contact: Mahir Tajwar, Department of Earth and Environmental Sciences, Vanderbilt University. Access note: Files are restricted; please contact the author to request access.