Characterisation of the nature, origins and ecological significance of dissolved organic matter in freshwater ecosystems

The UN has listed coastal nutrient pollution and hypoxia as the one of the greatest current threats to the global environment. Impacts include eutrophication of coastal waters and oxygen depletion, and the associated damage to ecosystems, biodiversity & coastal water quality. The UNEP Manila Declaration (Jan 2012) identifies nutrient enrichment of the marine environment as one of 3 foci for its Global Programme of Action for the Protection of the Marine Environment from Land-based Activities, and this was one of the key foci at the Rio+20 UN Conference on Sustainable Development, June 2012.

Simultaneously, the International Convention on Long-Range Transboundary Air Pollution (CLRTAP) is revising Annex IX of the Gothenburg Protocol (to Abate Acidification, Eutrophication & Ground-level Ozone) to further reduce the emission of ammonia from land-based activities, and in Europe the control of nutrient flux to all freshwaters & the coastal zone is required in order to meet the target of restoring waters to Good Ecological Status under the EU Water Framework Directive.

Evidence indicating that nutrient flux to waters is increasing worldwide is clear. Although N & P concentrations have recently levelled off or decreased in some European catchments, in others an increase is reported, particularly in rivers draining through rapidly developing economic regions. A rising trend in Dissolved Organic Carbon (DOC) flux to freshwaters & coastal areas such as the Baltic Sea is also widely reported, particularly across the North Temperate & Boreal regions, where N & P export to the coastal zone continues to rise. Impacts on ecosystem health are extensive & undesirable in both freshwaters & coastal waters, & there are implications for human health where DOC & DON are also known to support carcinogen formation in water supplies.

A detailed understanding of the nature, origins & rates of nutrient delivery to waters is essential if we are to meet the target of control through management intervention, yet much of the necessary evidence base is lacking. Routine nutrient monitoring in waters is largely based on inorganic nutrient fractions, and substantially underestimates the total nutrient flux from source to sea, while research confirms that dissolved organic matter (DOM) plays an important role in ecosystem function including supporting microbial metabolism, primary production and pollutant transport, suggesting that its oversight in routine monitoring may undermine international efforts to bring nutrient enrichment impacts under control.

Here, we address this knowledge gap, building on the specific expertise of project members, undertaking a suite of interlinked experimental & observational research from molecular to catchment scale. We will use a combination of well-established approaches widely used in catchment research, with a range of cutting-edge approaches which are novel in their application to nutrient cycling research, or employ novel technologies, bringing new insights into the process controls on nutrient cycling at a molecular to river reach scale.

The programme will deliver improved understanding of:

1. the role of DOM in the transport of N & P from source to sea & the ways in which this might alter nutrient delivery to freshwaters & the coastal zone under a changing climate;
2. the ecological significance of DOM as a source of nutrient uptake & utilisation by algal, plant and microbial communities in waters of contrasting nutrient status & DOM character; and
3. the impacts of DOM flux from soils, livestock & human waste fluxes on the ecological status, goods & services provided by freshwaters.

It will also deliver knowledge exchange between the 5 groups & the wider science community, and have an impact beyond the lifetime of this project, building capacity through staff & PhD appointments in a field where current understanding is uncertain, undermining business planning and international policy development.

Impact in the user community will primarily be realised through the development of KE partnerships with those involved in policy and operational management of the environment. To this end, we have held a suite of meetings and discussion sessions with a wide range of stakeholders prior to finalising our proposal, in order to ensure that their interests and concerns are properly represented in the programme, and that the science we propose is transferable and useful beyond the immediate academic beneficiaries.

Ten stakeholder organisations have agreed to join the programme as Project Partners, providing access to data and infrastructure assets, staff expertise, project placements and training. These include Government organisations (Defra, Environment Agency, Natural England, Countryside Council for Wales, Drinking Water Inspectorate), charities (The Rivers Trust), and the water utilities including Wessex Water (Hampshire Avon), Welsh Water (Conwy) and Scottish Water who have significant problems associated with DBP formation in a number of their water supply catchments.

In addition, we propose to develop a number of novel technologies under the proposed programme, including the testing of novel sensor technologies to capture high resolution information on CDOM flux at catchment scale, and the development of a novel proteomic/metabolomics approaches to allow holistic study of the metabolic processes controlling nutrient utilisation by microbial communities, and characterisation of the enzymatic functions involved. The group at Bangor is world-leading in this field, and we have secured a letter of support from Manuel Ferrer, Institute of Catalysis, Madrid confirming his support for and involvement in the development of this technology and its application to this project.

Our Impact Plan will deliver KE through a five step process:

1. all Project Partners have participated in the final formulation of this bid, providing valuable suggestions to hone the programme to ensure that anticipated outcomes meet their interests and operational needs; they will join the Project Board to establish a programme of placements and working partnerships with programme staff and PhD students, participating in a start-up workshop to refine the proposed sampling programme, to ensure that this capitalises on existing data, infrastructure assets and focus areas for our partner organisations;
2. we will produce a series of briefing notes on specific policy implications of our research findings for our Project Partner organisations throughout the programme making these publicly available through our project website and the publicity activities of our Project Partner organisations;
3. we will develop links with the wider stakeholder community through the project website and existing KT networks in which we are already involved in our Hampshire Avon and Conwy research, and will ensure wider public engagement through University Science Days and local and national media;
4. we will engage with the wider academic community through: (i) free weekly access for external researchers to our quantitative data via our website; (ii) publication of 10 core papers in international peer reviewed journals, a suite of integrative papers in a special issue of Global Biogeochemical Cycles, and an overarching paper in Nature Geoscience on the 'Environmental Role and Significance of DOM Flux in Freshwaters'; (iii) presentation of our findings at international conferences, and (iv) a contribution to Planet Earth;
5. we will to host an end-of-programme interactive workshop on 'The Role and Management of DOM in Freshwater Systems' for our Project Partners and the wider stakeholder community, and will host an international research meeting at The Royal Society on 'The Global Significance of DOM in Potable, Inland and Coastal Waters' with a programme of invited international speakers, focusing on KE with the wider international research community.