Penny J. Johnes is an environmental scientist by background who has worked on the biogeochemistry of aquatic systems, and the impacts of food production and environmental change on the quality of inland and coastal waters for the past 30 years. She has provided advice to a range of UK Government and international agencies on the nature and scale of nutrient enrichment in waters, the consequences of this enrichment for ecosystem health, and the most effective strategies for the control of nutrient flux from land basd sources to waters. She is currently a member of the UNECE Task Force for Reactive Nitrogen and its Expert Panel on Nitrogen Budgets, is a member of the IAHS International Commission on Water Quality, sits on the Natural England Science Advisory Committee, Wessex Water Catchment Panel, Defra Biodiversity Targets Advisory Group, Defra Nutrient Management Expert Group, and is Chair of the Defra Water Expert Advisory Group.