Physicochemical and biological variables measured in 110 national monitoring lakes between 1992 and 2022. Physicochemical and biological variables measured in 110 national monitoring lakes between 1992 and 2022. 2025-136-1 SLU.ma.2025.IÄ-2 https://doi.org/10.5878/03t1-sv66 Swedish National Data Service Svensk nationell datatjänst Landing page Physicochemical and biological variables measured in 110 national monitoring lakes between 1992 and 2022. Physicochemical and biological variables measured in 110 national monitoring lakes between 1992 and 2022. 2025-136-1 SLU.ma.2025.IÄ-2 https://doi.org/10.5878/03t1-sv66 10.1111/gcb.70274 Johnson, Richard Johnson, Richard Swedish National Data Service Svensk nationell datatjänst Landing page LAKE/POND freshwater biology freshwater ecosystem sötvattensekosystem freshwater monitoring freshwater sötvatten environmental monitoring miljöövervakning freshwater ecosystem sötvatten Environmental monitoring facilities Anläggningar för miljöövervakning Environment Miljö Inland Waters Sjöar och vattendrag Physicochemical and biological data 110 national monitoring lakes for the years 1992 to 2022 were downloaded from the data host https://miljodata.slu.se/MVM/. Climate data were extracted from Climate Research Unit gridded Time Series dataset (version 4.06; Harris et al., 2020; https://crudata.uea.ac.uk/cru/data/hrg/) Eight data sets were compiled: 1. Physicochemical variables from surface water samples (10 variables): EU id Year Colour_absorbance_420nm Ca mg/l Conductivity_mS/m pH TOC mg/l C DIN_ µg/l_N TP_ µg/l_P Water_Temperature_°C. Lake physicochemical and climate data were log10(x + 1) transformed to approximate normal distribution prior to the analyses. 2. Climate data: annual mean air temperature (°C) and precipitation (mm per month for each lake in each year) extracted from the interpolated Climate Research Unit gridded Time Series dataset (version 4.06; Harris et al., 2020; https://crudata.uea.ac.uk/cru/data/hrg/) 3. Phytoplankton taxon abundances (biovolumes) for individual taxa collected in August (n = 780 taxa). Biovolumes were Hellinger transformed. 4. Phytoplankton metrics (n=5): number of taxa, taxon biovolumes, diversity (Hills N2), % cyanobacteria and between-year Euclidean distance*. 5. Littoral taxon abundances (numbers per unit effort) for samples collected in October/November (n=681 taxa). Abundances were Hellinger transformed. 6. Littoral metrics (n=4): number of taxa, total abundance, diversity (N2) and between-year Euclidean distance 7. Profundal taxa abundances (individual per m2) for samples collected in October/November (n=321 taxa). Abundances were Hellinger transformed. 8. Profundal metrics (n=4): number of taxa, total abundance, diversity (N2) and between-year Euclidean distance. * Between-year Euclidean distances were calculated using detrended correspondence analysis axes 1-3 as as d=√((x2 – x1)² + (y2 – y1)²) + (z2 – z1)²), where x1, y1, z1 represent DC axis scores one, two and three, respectively, at any year and x2, y2, z2 represent DC axis scores one, two and three, respectively, for the previous year. 1992-03-01 2022-11-30 Sweden Sverige Numeric Sampling and analyses of all abiotic and biological variables were based on standard protocols throughout the study period. These protocols are quality controlled and certified by the Swedish Board for Accreditation and Conformity Assessment (SWEDAC; https://www.swedac.se/). All physicochemical and biological analyses were performed at the Department of Aquatic Sciences and Assessment following international (ISO) or European (EN) standards (Fölster et al., 2014). Detailed information concerning methods and quality control can be found at https://www.slu.se/en/departments/aquatic-sciences-assessment/laboratories/vattenlabb2/. In brief, for physicochemical measurements mid-lake surface water samples (0.5 m) were taken annually during four sampling intervals (March to November) using a Plexiglas sampler. Phytoplankton was sampled quantitatively in late summer (August) with a tube sampler from the epilimnion in the open-water mid-lake area. Benthic macroinvertebrate samples were collected in autumn (mainly October/November) from littoral and profundal habitats. For littoral habitats, macroinvertebrates were collected using standardised kick sampling with a hand net (0.5 mm mesh). Five standardised kick samples (20-s duration, 1 m long, ca 0.5–1 m depth) were taken from stony, vegetation-free sites in each lake. For profundal macroinvertebrate collections consisted of five Ekman grab samples (247 cm2) taken within a 150 m x 150 m quadrate situated over the deepest area of the lake, washed through a 0.5 mm mesh and preserved in 70% ethanol (final concentration).Sampling and analyses of all abiotic and biological variables were based on standard protocols throughout the study period. These protocols are quality controlled and certified by the Swedish Board for Accreditation and Conformity Assessment (SWEDAC; https://www.swedac.se/). All physicochemical and biological analyses were performed at the Department of Aquatic Sciences and Assessment following international (ISO) or European (EN) standards (Fölster et al., 2014). Detailed information concerning methods and quality control can be found at https://www.slu.se/en/departments/aquatic-sciences-assessment/laboratories/vattenlabb2/. In brief, for physicochemical measurements mid-lake surface water samples (0.5 m) were taken annually during four sampling intervals (March to November) using a Plexiglas sampler. Phytoplankton was sampled quantitatively in late summer (August) with a tube sampler from the epilimnion in the open-water mid-lake area. Benthic macroinvertebrate samples were collected in autumn (mainly October/November) from littoral and profundal habitats. For littoral habitats, macroinvertebrates were collected using standardised kick sampling with a hand net (0.5 mm mesh). Five standardised kick samples (20-s duration, 1 m long, ca 0.5–1 m depth) were taken from stony, vegetation-free sites in each lake. For profundal macroinvertebrate collections consisted of five Ekman grab samples (247 cm2) taken within a 150 m x 150 m quadrate situated over the deepest area of the lake, washed through a 0.5 mm mesh and preserved in 70% ethanol (final concentration). Measurements and testsMeasurements and tests Mätningar och testerMätningar och tester Access to data through SND. Data are freely accessible. Åtkomst till data via SND. Data är fritt tillgängliga. openAccess Johnson, R.K., Goedkoop, W., Lau, D. (2025). Multi-decadal trends in Northern lakes show contrasting responses of phytoplankton and benthic macroinvertebrates to climate change. Global Change Biology, http://dx.doi.org/10.1111/gcb.70274 Johnson, R.K., Goedkoop, W., Lau, D. (2025). Multi-decadal trends in Northern lakes show contrasting responses of phytoplankton and benthic macroinvertebrates to climate change. Global Change Biology, http://dx.doi.org/10.1111/gcb.70274 10.1111/gcb.70274 2025