This dataset contains high frequency sampling of key parameters to ensure the collection of consistent data for the long-term records in four lakes of Sierra Nevada, Spain (Laguna de la Caldera, Laguna de Río Seco, Laguna Larga, and Laguna-embalse de las Yeguas). A feature that makes Sierra Nevada unique is that lakes undergoes high inputs of nutrient-rich aerosols due to their proximity to the Sahara. Sampling was carried out during the ice-free period of 2022 to monitor biological and biochemical impact of an unusual year of intense aerosol inputs from the Sahara that clouded Sierra Nevada’s shallow lakes “chocolate-coloured” at the beginning of the ice-free period. Parameters include water quality (nutrients, major cations and anions), biological (bacteria and zooplankton) and hydrological data collected in periodic sampling using water samplers, sediment traps and plankton nets. Multiparametric probes provided real-time and continuous data on multiple parameters simultaneously.

This dataset comprises the simultaneous monitoring of about 50 high mountain lakes in the Spanish’s Sierra Nevada carried out in collaboration with government agencies and local communities as part of a citizen science campaign. Standard monitoring protocols were used to collect data on various physical (temperature, pH, dissolved oxygen, water clarity), chemical (nutrients, major cations and anions, chlorophyll a, alkalinity), and biological parameters (bacteria, zooplankton) in two successive years. High mountain lakes are ideal sites to study and understand global change processes. The utilisation of these systems as sentinels of global change can be attributed to various characteristics, such as: modest catchment areas, oligotrophic waters with limited nutrients, remote accessibility, relatively good ecological health, elevated altitudes and harsh environmental conditions, or the presence of relatively uncomplicated biological communities with rapid renewal rates, among others. The involvement of the community in Sierra Nevada Long-Term Monitoring Programs serves as an invaluable complement to scientific endeavours aimed at monitoring environmental changes, as it contributes to alleviate personnel and resource shortcomings (Villar-Argaiz et al. 2022).

Measurements of lake chemistry are part of lake monitoring, which is usually carried out by monthly sampling at many regular lake sites (5 to 17 sites depending on the intensity of the measurements over the years). The integrated sample represents the whole water column of this polymictic shallow lake with a mean lake depth of 1.2m. The measurement satisfy the analytical standards of Ö-Norm in Austria.