Background

Nitrogen (N) flux to waters is increasing worldwide as a function of the intensification and expansion of agriculture, car use and other fossil-fuel combustion in both developed and developing countries, while increased concentrations of phosphorus (P) from agricultural sources and human waste are a major cause of degradation in the ecological status of inland waters. 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 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. 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.

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. The DOMAINE project will 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. The DOMAINE project will deliver improved understanding of:

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 cimate.

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.

The impacts of DOM flux from soils, livestock & human waste fluxes on the ecological status, goods & services provided by freshwaters.