This dataset includes measured DOC concentration, and modelled DOC concentration derived from UV-visible absorbance spectra. We also include measured chlorophyll concentration, pH and conductivity. The natural water samples were collected from freshwater ecosystems in the UK, and site names and locations. Samples were also collected at set intervals throughout the year, from mesocosm experiments simulating natural lake ecosystems. Data on measured and modelled DOC concentration, chlorophyll concentration, pH and conductivity for the mesocosms sampled, are also included. Full details about this dataset can be found at https://doi.org/10.5285/6abbc357-1b69-49b4-be28-a77eb7bc6c7f

This dataset describes the concentrations of photosynthetic pigments (Chlorophylls, carotenoids and phycocyanin) measured by HPLC and spectrophotometry in water samples of 20 lochs in Scotland. Data were collected between May and June 2022. Full details about this dataset can be found at https://doi.org/10.5285/7794cbfa-1d74-4885-b303-8c20f4608728

This dataset includes catchment stream inflow and outflow rates, secchi depth, chlorophyll, phytoplankton counts and nutrient concentrations for the lake, inflow, outflow and groundwater spring. The measurements are from a PhD research project at Rostherne Mere in Cheshire. These data were collected to show the relationship between the catchment hydrology and in-lake nutrient loads for assessment of the current catchment nutrient budget. The monitoring study covered a period from January 2016 to January 2017. All data is presented with date, flow rate, nutrient and chlorophyll concentrations and phytoplankton species abundance. The work was carried out as part of a Natural Environment Research Council (NERC) funded PhD [grant number NE/L002493/1]. Full details about this dataset can be found at https://doi.org/10.5285/5c6b2bcb-6b10-4c57-a595-ce94a655e709

This dataset consists of phyto- and zooplankton counts, chlorophyll concentration and fish catch data from the Cumbrian Lakes (Blelham Tarn, Esthwaite Water, Windermere north and south basins). The data span the years 1940 to 2013 but time series vary in length among different species and sites, and fish data are only available from Windermere. The original data were initially collected by the Freshwater Biological Association (FBA) but have been collected by CEH and its predecessor Institute of Freshwater Ecology (IFE) since 1989. Full details about this dataset can be found at https://doi.org/10.5285/1de49dab-c36e-4700-8b15-93a639ae4d55

A subset of the Loch Leven long-term monitoring project dataset. This subset contains data collected from Loch Leven between 1985 and 2007 at three sampling sites in the lake. It includes results of chlorophyll, phosphorus, and silicon analyses as well as conductivity and water temperature measurements. The data relate to water samples taken at fortnightly or monthly intervals. Data available in digital form is described here. Additional data currently held as hard copy, will become available once digitised. Full details about this dataset can be found at https://doi.org/10.5285/2969776d-0b59-4435-a746-da50b8fd62a3

Zooplankton faecal pellet abundance, volume and flux were determined from samples collected at three stations in the Scotia Sea, Southern Ocean during cruise JR304. Samples were collected at six depths within the 0 - 400 m epi- to upper mesopelagic using Niskin bottles attached to a CTD unit and were preserved in a formalin-based solution. Fluorescence data were collected during the same deployments. Sampling was performed by C. Liszka and G. Tarling on board RRS James Clark Ross. Sample analysis was performed by C. Liszka at British Antarctic Survey in Cambridge.

This data release includes sensor data collected from Conductivity Temperature Depth (CTD) casts during a field campaign to Kongsfjorden in July 2024 as part of the NERC funded SiCLING project (Silicon Cycling in Glaciated Environments), led by Dr. K. Hendry from the British Antarctic Survey. Thirteen CTD casts were carried out in a transect along the fjord. Funding: NERC Pushing the Frontiers grant SiCLING (NE/X014819/1).

This data release includes sensor data collected from Conductivity Temperature Depth (CTD) casts during a field campaign to Ryder Bay in January 2025 as part of the NERC funded SiCLING project (Silicon Cycling in Glaciated Environments), led by Dr K. Hendry from the British Antarctic Survey. Four CTD casts were carried out within the Bay. This research aims to investigate the release of biologically important nutrients and trace elements from glacial sediments in polar coastal environments, and the biogeochemical impact of ongoing glacier retreat. Funding: NERC Pushing the Frontiers grant SiCLING (NE/X014819/1).

This is a long-term monitoring dataset of surface temperature, surface oxygen, water clarity, water chemistry and phytoplankton chlorophyll a from weekly to fortnightly sampling at Grasmere in Cumbria, England that began in 1968 for some variables. The data were initially collected by the Freshwater Biological Association but have been collected by the Centre for Ecology & Hydrology (CEH) and its predecessor Institute of Freshwater Ecology since 1989. The data available to download comprise surface temperature (TEMP) in degree Celsius, surface oxygen saturation (OXYG) in % air-saturation, Secchi depth (SECC) in metres, alkalinity (ALKA) in µg per litre as CaCO3 and pH. Ammonium (NH4N), nitrate (NO3N), soluble reactive phosphate (PO4P), total phosphorus (TOTP), dissolved reactive silicon expressed as SiO2 (SIO2) and phytoplankton chlorophyll a (TOCA) are all given in µg per litre. Measurements are made from a boat at a marked location (buoy) at the deepest part of the lake. When it was not possible to visit the buoy, samples were taken from the shore, thus water samples were not integrated on these occasions, marked as Flag 2. All data are from June 1968 until the end of 2013. Full details about this dataset can be found at https://doi.org/10.5285/b891c50a-1f77-48b2-9c41-7cc0e8993c50

This dataset contains biogeochemical measurements of surface water, sampled across Loch Etive, Scotland, between the 3rd and 7th of October 2022. The dataset encompasses 23 locations including nine open loch stations, four fish-farm adjacent loch sites, six river inflows, and four process experiment river sites, enabling a comparison of water chemistry across marine, freshwater, and anthropogenically influenced environments. Surface water samples were collected and analysed for an extensive range of biogeochemical parameters. In-field measurements included water temperature, pH, dissolved oxygen, and specific conductivity. Laboratory analyses comprised: - Alkalinity - Major nutrients, including nitrate, nitrite, ammonium, soluble reactive phosphorus (SRP), and silica - Dissolved and total organic and inorganic carbon and nitrogen (DOC, TIC, TDN) - Trace elements and rare earth elements (REEs), including lithium, barium, aluminium, and a full suite of lanthanides - Stable isotope composition of oxygen (δ18O), determined via isotope ratio mass spectrometry - Chromophoric and fluorescent dissolved organic matter (CDOM/FDOM), with derived indices such as fluorescence index (FI), biological index (BIX), and humification index (HIX) In addition to water chemistry, particulate samples were collected and analysed for total suspended solids (TSS), particulate organic matter (POM), particulate inorganic matter (PIM), chlorophyll-a concentration, and particulate organic carbon/nitrogen (POC/PON). Phytoplankton community composition was assessed by flow cytometry, quantifying major groups including diatoms, pico- and nano-chlorophytes, cryptophytes, and cyanobacteria. This comprehensive dataset is intended to inform biogeochemical process understanding in polar analogue environments and to validate analytical workflows and inter-institutional protocols. Full details about this dataset can be found at https://doi.org/10.5285/50f4344e-a79a-4e1f-a9ee-e7985ed847cd