Professor Penny Johnes
BSc, D.Phil (Oxon.)
Current positions
Professor of Biogeochemistry
School of Geographical Sciences
Contact
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Research interests
Penny 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.
Penny has particular interests in the role of dissolved organic matter as a driver of biodiversity loss in freshwater ecosystems, the potential to develop holistic management strategies which tackle multiple stressors in freshwaters and their catchments, and in ensuring that environmental management policy is underpinned by robust science evidence. She works with researchers across a range of disciplines to meet these challenges, from chemical to biological, environmental, earth, agricultural, social economic and political sciences.
Her research to date has highlighted the quantitative importance of organic and particulate nitrogen and phosphorus fractions in the total nutrient load transported to and within water bodies; the importance of short-term, extreme flow conditions in controlling the nutrient source/sink function in soils, wetlands and freshwaters; and the necessity when upscaling findings from local to national scale, of defining quasi-homogenous geoclimatic units exerting broadly similar controls on nutrient flux from land to water, as the base unit for modelling. This research has been critical in helping us to better understand the sources of pollutants within the landscape, the pathways by which material moves from land to stream under differing environmental conditions, and the rates at which this material is cycled, transported and transformed instream.
Penny's ongoing research includes work characterising the signature of dissolved organic matter (DOM) flux in freshwater systems in relation to nutrient enrichment and climatic controls, funded under a NERC Large Grant (the DOMAINE programme), and a major programme funded by the UK Department of Environment, Food and Rural Affairs, and Environment Agency established to test the hypothesis that it is possible to reduce cost-effectively the impact of agricultural diffuse water pollution on ecological function while maintaining sustainable food production through the implementation of multiple on-farm mitigation measures (the Demonstration Test Catchments Programme). These programmes capitalise on recent novel analytical and in situ monitoring technologies to elucidate the fine scale variability in nutrient flux behaviours and source character in catchments, and the ways in which the hydrochemical signature of nutrient flux from catchments, defined at high resolution, may be used to diagnose the stresses on that system and their likely responses to proposed on-farm mitigation efforts.
Projects and supervisions
Research projects
SMARTWATER: Diagnosing controls of pollution hot spots and hot moments and their impact on catchment water quality
Principal Investigator
Role
Co-Investigator
Description
Planetary boundaries of river water pollution are at risk of being breached, with dangerous consequences for human and environmental health, economic prosperity, and water security. The current paradigm for environmental…Dates
01/11/2023 to 31/10/2028
Quantifying the combined nutrient enrichment, pathogenic, and ecotoxicological impacts of livestock farming on UK rivers
Principal Investigator
Description
Livestock farming is the dominant farming type and source of organic matter pollution in UK freshwaters, with over 9.65M cattle and 32.7M sheep on 10M hectares of grassland, representing 57%…Managing organisational unit
School of Geographical SciencesDates
01/11/2022 to 16/04/2026
Quantifying the combined nutrient enrichment, pathogenic, and ecotoxicological impacts of livestock farming on UK rivers
Principal Investigator
Description
Livestock farming is the dominant farming type and source of organic matter pollution in UK freshwaters, with over 9.65M
cattle and 32.7M sheep on 10M hectares of grassland, representing 57% of…Managing organisational unit
School of ChemistryDates
01/11/2022 to 16/04/2026
MIDST-CZ: Maximising Impact by Decision Support Tools for sustainable soil and water through UK-China Critical Zone science
Principal Investigator
Managing organisational unit
School of Geographical SciencesDates
01/01/2019 to 31/03/2022
Thesis supervisions
Is photodegradation the critical pathway in the transformation of DOM in aquatic systems during autumn and winter
Supervisors
Determination of the nature and origins of phosphorus in catchments underlain by Upper Greensand
Supervisors
Investigating the bioavailability of dissolved organic nitrogen using freshwater algae
Supervisors
Anthropogenic and lithological controls on production and bioavailability of mineral nutrients in agricultural karst critical zones
Supervisors
Molecular investigations of the nature, occurrence and behaviour of myo-inositol hexakisphosphate in soils using ion chromatography and high-resolution mass spectrometry
Supervisors
Do oxalic acid exudates from mycorrhizal fungi influence the uptake of phosphorus by primary producers in the karst critical zone of south west China?
Supervisors
Untargeted Chemometric Characterisation of High Resolution Orbitrap Mass Spectra of Riverine and Point Source Dissolved Organic Matter
Supervisors
Freshwater Picocyanobacteria and their Organic Diet
Supervisors
Molecular insights into the role of particulate organic matter in biogeochemical cycling in freshwater ecosystems
Supervisors
Publications
Selected publications
08/03/2020Dissolved organic nutrient uptake by riverine phytoplankton varies along a gradient of nutrient enrichment
Science of The Total Environment
Microbial uptake kinetics of dissolved organic carbon (DOC) compound groups from river water and sediments
Scientific Reports
Determining patterns in the composition of dissolved organic matter in fresh waters according to land use and management
Biogeochemistry
Recent publications
26/02/2023Investigating biotic uptake of riverine organic nitrogen using a compound-specific stable-isotope probing approach.
Draft Genome Sequences of Synechococcus sp. strains CCAP1479/9, CCAP1479/10, CCAP1479/13, CCY062, and CCY9618
Journal of Genomics
Exploring the nature, origins and ecological significance of dissolved organic matter in freshwaters: state of the science and new directions
Biogeochemistry
What do macroinvertebrate indices measure? Stressor-specific stream macroinvertebrate indices can be confounded by other stressors
Freshwater Biology
Dissolved Organic Matter in Freshwater Ecosystems
Dissolved Organic Matter in Freshwater Ecosystems