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

Lead Research Organisation: NERC Centre for Ecology and Hydrology
Department Name: Water Resources (Lancaster)

Abstract

Evidence indicating that nutrient flux to inland and coastal waters is increasing worldwide is clear. Despite significant management effort to reduce theses fluxes, while 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 in the N Temperate & Boreal regions. 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.

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, while the UNECE Convention on Long-Range Transboundary Air Pollution (CLRTAP) is currently 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.

Simultaneously, 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.

A detailed understanding of the nature, origins & rates of nutrient delivery to waters is essential if we are to control these impacts through management intervention, yet much of the necessary evidence base is lacking. Routine water quality monitoring is largely based on inorganic nutrient fractions, and substantially underestimates the total nutrient flux to waters, 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.

Planned Impact

Impact in the user community will 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.

Nine stakeholder organisations have agreed to join us 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), charities (The Rivers Trust), and the water utilities including Wessex Water (Hampshire Avon), Welsh Water (Conwy) and Scottish Water who have significant problems with DBP formation in a number of their water supply catchments.

We will also develop a number of novel technologies, 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 Dr Ferrer, Institute of Catalysis, Madrid confirming his support for and involvement in the application of this technology to this project as a Project Partner.

We will deliver KE through a 5 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, establish a programme of placements and working partnerships with staff and PhD students, and participate in a start-up workshop to refine the proposed sampling programme, to ensure that this capitalises on their existing data, infrastructure assets and focus areas;
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 high frequency quantitative data; (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 on the 'Environmental Role and Significance of DOM Flux in Freshwaters'; (iii) feedback on our findings to the international policy arena through our participation as expert members of the IPCC, UNECE Task Force for Reactive N and UNEP Foresight programmes, (iv) 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 invited international speakers, focusing on KE with the wider international research community.

Publications


10 25 50
 
Description Our part of this grant has recently begun. The periphyton and phytoplankton bioassays at six sites in the Conwy and Avon to test the bioavailability of organic nitrogen and phosphorus have commenced.
We have now completed one full year of inorganic and organic nutrient bioassay experiments across six sites within the Tier 1 catchments at approximately bi-monthly frequency. These sites represent a gradient of organic and inorganic nutrient concentrations. Growth responses by phytoplankton and epilithic communities at each site have been examined in relation to eight different organic N and P compounds, which differ in terms of molecular weight and lability. Initial results suggest that the majority of the organic nutrient compounds tested are readily utilised by the phytoplankton community, although the response for the epilithic algae is less clear. There appear to be distinct patterns in organic nutrient use across sites, with inorganic bioassays confirming that, on average, the majority of sites are phosphorus limited, with the more upland sites being co-limited by phosphorus and nitrogen. Seasonal patterns in organic nutrient use and the extent of nutrient limitation are also apparent at some sites and the cause of this requires further investigation. To address the hypothesis in Objective 4b we have also carried out organic nutrient bioassays on rooted and unrooted macrophytes. Samples of a common moss and Ranunculus species were taken from one site in each of the Tier 1 catchments. Their biomass, growth rate and cellular nutrient content have been assessed following a one month incubation period with the same nutrient treatments as for the algae. Initial results from this work indicate that mass and relative growth rate increased more for the unrooted than rooted macrophyte species tested in the different organic nutrient treatments.
Exploitation Route The work currently suggests that organic nitrogen and phosphorus may be bioavailable in rivers. This is an important finding of relevance to organisations with a responsibility for managing water quality worldwide.
Sectors Agriculture, Food and Drink,Communities and Social Services/Policy,Environment
 
Description NERC DOMAINE programme: Project Partner 1 
Organisation Government of the UK
Department Department For Environment, Food And Rural Affairs (DEFRA)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution Provision of access to data, new knowledge, data digests and infrastructure, invited participation on stakeholder workshops, and Programme Advisory Board
Collaborator Contribution Access to Demonstration Test Catchments data, infrastructure, staff time, Project Partner participation in Programme Advisory Board
Impact None yet. Programme started 01 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 1 
Organisation Government of the UK
Department Environment Agency
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution Provision of access to data, new knowledge, evidence to underpin policy, infrastructure, participation in stakeholder workshops, access to programme website, membership of Programme Advisory Board
Collaborator Contribution Provision of access to infrastructre, long-term and 3rd Party data, provision of staff time input to the programme, membership of Programme Advisory Board, provision of staff placements for project staff to work with Agency staff
Impact None yet. Programme started 1 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 3 
Organisation Natural England
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution Provision of access to data, new knowledge, evidence to underpin policy, participation in stakeholder workshops, membership of Programme Advisory Board
Collaborator Contribution Provision of access to River Avon Catchment Sensitive Farming sites and 5 days staff time input per year, to include attendance at Programme Advisory Board meetings
Impact None yet. Project started 1 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 4 
Organisation Rivers Trust
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Charity/Non Profit 
PI Contribution Provision of access to data, infrastructure and guidance to underpin practical management in the field, including participation in stakeholder workshops and membership of Programme Advisory Board
Collaborator Contribution Provision of field support for project staff in the Hampshire Avon and Conwy catchments, 10 days per year technical input and assistance with dissemination of research findings
Impact None yet. Project started 1 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 5 
Organisation Wessex Water
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Private 
PI Contribution Provision of access to data, new knowledge and evidence to underpin business planning, participation in stakeholder workshops and membership of Programme Advisory Board
Collaborator Contribution Provision of Sewage Treatment Works effluent quality data, staff attendance at Programme Advisory Board and stakeholder workshops, and provision of river ecology data for the Hampshire Avon
Impact None yet. Project started 1 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 6 
Organisation European Commission (EC)
Department Spanish National Research Council (CSIC)
Country European Union (EU) 
Sector Public 
PI Contribution Provision of samples for analysis, joint authorship of publications, attendance at stakeholder workshops and membership of Programme Advisory Board
Collaborator Contribution Provision of metabolomic analysis on 150 samples, provision of meta-proteomic analysis on 10 samples, attendance at stakeholder workshops and 4 days staff time for attendance at project and Programme Advisory Board meetings
Impact None yet. Project started 01 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 7 
Organisation Scottish Water
Department Scottish Water (Glasgow)
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution Provision of access to data, infrastructure and evidence to support business planning, participation in stakeholder workshops and membership of Programme Advisory Board
Collaborator Contribution Provision of access to data assets and infrastructure, 5 days staff time input per year and a placement opportunity for PhD student 1 in Year 3 of their study.
Impact None yet. Project started 01 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 8 
Organisation Welsh Water
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Private 
PI Contribution Provision of access to data, new knowledge, evidence to underpin business planning, participation in stakeholder workshops and membership of Programme Advisory Board
Collaborator Contribution Access to data assets and infrastructure, 5 days staff time per year and in-kind support for PhD 1 studentship
Impact None yet. Started 01 April 2014
Start Year 2014
 
Description NERC DOMAINE programme: Project Partner 9 
Organisation Cardiff University
Department Wales Institute for Cognitive Neuroscience
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Charity/Non Profit 
PI Contribution Provision of access to data, new knowledge and evidence to underpin policy, participation in stakeholder events, membership of Programme Advisory Board
Collaborator Contribution Access to CCW data assets for the Conwy, 5 days staff time input per year and participation in Programme Advisory Board
Impact None yet. Project started 01 April 2014
Start Year 2014
 
Description Cumbrian Lakes Research Forum 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Over 40 delegates from 15 organisations attended to hear about the research being carried out on Cumbrian lakes from NERC funded grants.
Year(s) Of Engagement Activity 2015
 
Description Poster presentation at the International organic phosphorus workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A poster entitled "Bioavailability of organic phosphorus across a riverine nutrient gradient" was presented at the international Organic Phosphorus workshop in September 2016.
Year(s) Of Engagement Activity 2016