21.15109/ARP/8LLWU4Horváth, HajnalkaHajnalkaHorváth0000-0002-8249-4934HUN-REN Balaton Limnological Research InstituteLong-term Nutrient Concentration Dataset (1985–2025) for the Siófok and Keszthely Basins of Lake BalatonARP2026Earth and Environmental SciencesHorváth, HajnalkaHajnalkaHorváthHUN-REN Balaton Limnological Research Institute2026-03-062026-03-2610.1007/978-1-4020-8379-2_1021850821965467494application/pdfapplication/pdftext/comma-separated-values1.0CC BY-NC-SA 4.0This dataset contains measurements of total and dissolved nutrient concentrations (NH₄–N, NO₃–N, urea–N, TDN, TN, SRP, TDP, TP) collected in Lake Balaton between 1985 and 2025 (with significant gaps). The data represent monitoring results from two basins: the Siófok Basin (EOV X: 175982; EOV Y: 564770) and the Keszthely Basin (EOV X: 156046; EOV Y: 514651).