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 set contains a record of nitrate concentrations and isotopic composition present within the drip waters and speleothem carbonate deposits of Cueva-cubío del Llanío, northern Spain. Data were collected between 2018 to 2020, and specifically address the nitrate composition of the cave drip waters, pool waters, rocks, soil, vegetation and contemporary speleothem carbonate. Calculations are also undertaken to assess the partitioning of nitrate between cave drip water and speleothem carbonate deposits. Data pertaining to speleothem nitrate content also extend to other cave locations (Pooles cavern, UK; Brown's Folly Mine, UK, Ease Gill Caverns, UK; Rukiesa cave, Ethiopia; Cueva Perlas, N. Spain). Sample analysis was performed at Lancaster University and the UK Centre for Ecology and Hydrology under NERC facility access grant LSMSF\CEH\L\125\11\2018. The data presented represent the full underlying dataset to Wynn et al., 2021, Chemical Geology: DOI.org/10.1016/j.chemgeo.2021.120172.

We surveyed two salt marshes in each of six estuaries (Solway, Morecambe Bay, Ribble, Humber, Blackwater, Chichester) between September and November 2024 to characterise national differences in denitrification rates and their relationship with potential drivers. A key ecosystem service in coastal systems is the remediation of nutrient pollution through sediment burial, vegetative uptake and microbial processing. Denitrification is a facultative anaerobic process where microbial activity transforms nitrate (NO3-), which in high concentrations can be environmentally harmful, into the environmentally benign dinitrogen gas (N2). Denitrification's magnitude is considered particularly important in saltmarsh systems compared to other habitats, although an intermediate product, nitrous oxide (N2O), can also be given off and contribute to climate change. Full details about this dataset can be found at https://doi.org/10.5285/26efc506-a265-4bb1-8296-d6988ab8d714

We surveyed two seagrass beds and two mudflats in each of six coastal sites in England (Holy Island, Blackwater, Thames, Chichester, Plymouth, Morecambe) between December 2024 and March 2025 to characterise national differences in denitrification rates and their relationship with potential drivers. A key ecosystem service in coastal systems is the remediation of nutrient pollution through sediment burial, vegetative uptake and microbial processing. Denitrification is a facultative anaerobic process where microbial activity transforms nitrate (NO3-), which in high concentrations can be environmentally harmful, into the environmentally benign dinitrogen gas (N2). Denitrification's magnitude is considered particularly important in saltmarsh systems compared to other habitats, although an intermediate product, nitrous oxide (N2O), can also be given off and contribute to climate change. This data accompanies the technical report "Denitrification dynamics and relationships with potential drivers across English saltmarshes, seagrass beds, and mudflats: Capturing national variation in space and time" Full details about this dataset can be found at https://doi.org/10.5285/ea9811f4-5856-4a7e-bbe6-dcea9c115ea2