Replication Data for: Land Use and Land Cover Control the Composition of Solid-Phase Extracted Dissolved Organic Matter in the Ebro and Mero Rivers (Spain)

This dataset provides detailed measurements of the chemical composition and optical properties of dissolved organic matter (DOM) collected along the Ebro and Mero River continua, from the headwaters to the estuarine zones. Samples were collected across different seasons to capture both spatial and temporal variability. The dataset includes the relative abundance of DOM fractions obtained through spectral deconvolution, performed using Gaussian fitting of synchronous fluorescence data, as well as measurements of optical properties and dissolved nutrients. These data enable the exploration of seasonal shifts and spatial gradients in DOM composition, with particular attention to how different land-use and land-cover (LULC) types influence the chemical characteristics of solid-phase extracted DOM obtained using PPL resins (styrene–divinylbenzene polymer with a polar surface modification) along the two Spanish rivers.