This dataset contains in-stream measurements of sediment porewater nutrients, nitrification rates (and the fraction which is either fully oxidised to nitrate or reduced to N2 gas), and the abundance of microbial 16S rRNA and specific N-cycling genes and transcripts. Sediments were sampled in winter (February 2018) and summer (July 2018), from 12 UK rivers with permeable beds (sand or chalk geology) and a gradient of P concentrations, in the Hampshire Avon catchment, Kent, and Essex. Methods included measurements of porewater nutrients using Skalar SAN++AutoAnalyser, nitrification rates from in-situ ‘push-pull’ injections of 15N-labelled ammonia and -nitrite, and sediment microbial gene and transcript abundance by DNA extraction and qPCR. The work was supported by the Natural Environment Research Council (Grants NE/P01142X/1, NE/P011624/1; A new dynamic for Phosphorus in RIverbed Nitrogen Cycling - PRINCe Full details about this dataset can be found at https://doi.org/10.5285/d432d96c-7aff-45a5-9d4b-37e4065afdd7
