Snell, MariaBarker, P. A.Surridge, B. W. J.Benskin, C. McW. H.Barber, N.Reaney, S. M.Tych, W.Mindham, D.Large, A. R. G.Burke, S.Haygarth, P. M.2020-04-072020-03-102019-03-01Snell, M. A., Barker, P. A., Surridge, B. W. J., Benskin, C. M. H., Barber, N., Reaney, S. M., Tych, W., Mindham, D., Large, A. R. G., Burke, S. and Haygarth, P. M. (2019) ‘Strong and recurring seasonality revealed within stream diatom assemblages’, Scientific Reports. Springer Science and Business Media LLC, 9(1). doi: 10.1038/s41598-018-37831-w.https://doi.org/10.1038/s41598-018-37831-wImproving stream water quality in agricultural landscapes is an ecological priority and a legislative duty for many governments. Ecosystem health can be effectively characterised by organisms sensitive to water quality changes such as diatoms, single-celled algae that are a ubiquitous component of stream benthos. Diatoms respond within daily timescales to variables including light, temperature, nutrient availability and flow conditions that result from weather and land use characteristics. However, little consideration has been given to the ecological dynamics of diatoms through repeated seasonal cycles when assessing trajectories of stream function, even in catchments actively managed to reduce human pressures. Here, six years of monthly diatom samples from three independent streams, each receiving differing levels of diffuse agricultural pollution, reveal robust and repeated seasonal variation. Predicted seasonal changes in climate-related variables and anticipated ecological impacts must be fully captured in future ecological and water quality assessments, if the apparent resistance of stream ecosystems to pollution mitigation measures is to be better understood.enThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Article