EPA Research Programme 2014-2020

APPLICATION FORM for Project-Based Awards

Section A1:Literature Review
There has been an increasing awareness of the importance of fluvial suspended sediments in the transport of nutrients from agricultural catchment1. Furthermore, studies have shown that a significant proportion of total P loads is transported in streams and rivers in particulate form or within the fluvial suspended sediments2 and it is well established that elevated P compounds may promote eutrophication and degradation of surface water quality3. Suspended sediment associated organic P4and humic-metal P complexes5 will be deposited on the river bed channel or on floodplains and its subsequent remobilisation must therefore have an important impact on the transport, delivery pathway and fate of organic P and humic-metal P complexes within agricultural catchments. Deposition on the river channel bed or floodplains can result in short or long term P storage. Similarly, remobilisation of river bed sediments coupled with bank erosion can reintroduce organic P and humic-metal P complexes to the river channel. Hence, information is required on organic P and humic-metal P fluxes, storage, mobilization and bioavailability within agricultural streams on a temporal and spatial scale for appropriate catchment scale management policies. Despite increased recognition of the importance of particulate sediment associated P within freshwater systems (particularly lakes), little attention has been given to organic P and humic-metal P complexes in suspended and streambed sediments within agricultural catchments, with most research heretofore focussing on organic P and humic-metal P complexes in soils and lentic sediments (lakes, reservoirs etc.)6. Few studies have specifically characterised and quantified organic P and humic-metal P species within streambed sediments7,8, and fewer still their reactivity and bioavailability, especially in fluvial suspended sediments9. Factors which affect the bioavailability of organic P forms and humic-metal P complexes in fluvial and streambed sediments are similar to those from lentic systems with some differences such as a general absence of anoxia (although it may be present under certain conditions), less ability to buffer sediment and P inputs from runoff and in some areas a greater potential for macrophyte growth10. Many studies have shown that in catchments with diffuse sources, episodic flooding events and runoff (as influenced by stream hydro-morphology and land management) control stream bed and suspended solid composition11. Hence, the concentration and form oforganic P/humic-metal P complexes and their link to macrophyte growth are likely impacted by fluvial and stream bed sediments, which is the main research hypothesis for this proposal.
1Pulley, S. et al. (2016) Hydrological Processes, 30, 5, 704-719
2Ballintine, D.J. et al., (2008) Journal of Hydrology, 357,140-151
3Sharpley, A.N. et al. (2015) AMBIO,44,S163-S179
4Ahlgren et al.(2006) Limnology & Oceanography, 51,5,2341-2348
5Liu, J. et al. (2015) Environmental Science & Technology, 49, 168-176
6McDowell, R.W.& Hill, S.J. (2015) Journal of Soils and Sediments, 2369-2379
7McDowell,R.W & Stewart,I.(2005) Chemical and Ecology, 21,1,11-22
8Zhang,W. et al. (2013) Plus One,8,10,e76525
9Su et al.(2014). Agriculture, Ecosystems and Environment,188,169-179
10Withers, P.J.A. & Jarvie, H.P. (2008) Science of the Total Environment,400,379-395
11Stutter,M.I. et al. (2009) Applied Geochemistry, 24,800-809
12Sharpley,A. (2016) Sci.Agric.,73,1,1-8.
Section A2:Pressures, Policy and Solutions
The proposal directly relates to challenge two and Sub-topic 2.b of the ERA-NET CofundWaterWorks2015 call announcement by addressing the impact of fluvial and stream bed sediments in agricultural catchment streams on surface water quality, as up to 90% of P from agricultural catchments may be in particulate form within suspended sediments. Little attention has been given to molecular level biogeochemical dynamics of phosphorus species mobilised by suspended sediments and streambed sediments in such aquatic environments and transferred from land to water in runoff or overland flow. Our project aims to advance the understanding of the stability and bioavailability of organic P and humic bound P species for in stream algal growth and degradation of water quality. In addition the proposal directly relates to Sub-topic 2.c relating to developing predictive models to simulate potential P loss or the impacts of climate change, land-use and land management practices on fluvial sediment P export. Predictive models appeal to policy makers and water managers as these models can provide solutions to problems under various scenarios quickly12. The results from the local-scale biogeochemical field work and laboratory-based experiments in Sub-topic 2.b on fluvial sediment bound P (focusing on organic P and humic-metal P complexes) in agricultural catchment streams alone will fill major knowledge gaps. In addition, the new process molecular level understanding will be scaled up by developing more realistic representations of biogeochemical transformations in agricultural catchments, which can be included in catchment-scale hydrological models. To our knowledge, the proposed approach has not been applied in such a cohesive manner, across multiple connected spatial and temporal scales. Indeed, the current understanding of biogeochemical processes and fluxes affecting P on fluvial and streambed sediments and their effects on water quality and ecosystem health is limited at best. So, the proposed research is innovative and at the leading edge of this interdisciplinary field.
In addition, thewill provide and exchange complementary research training and knowledge for the Irish partner and the two other consortium partners in a number of key areas. The action will specifically fulfill the following research training and exchange objectives.
  1. Training and transfer of knowledge between consortium partners in experimental isotope biogeochemistry and hydrology, through method development, design and running of fluvial suspended sediment sampling campaigns under fluctuating flow and redox conditions.
  2. Training between consortium partners in advanced environmental analytical techniques, including the application to fluvial sediments of XANES and EXAFS.
  3. Training in biogeochemical modeling, by developing comprehensive reaction networks that describe the behaviour of P on redox-dynamic fluvial sediments
Identify Pressures
The EUTROSED project (and in particular TCD contribution to the overall project) will quantify the amount of P in particulate form within suspended sediments in four small agricultural catchments. This should help to determine the source of such Pin the rivers, for example whether from direct inputs related to anthropogenic activity and/or resuspension in the river which may be related to stream management and access issues within such agricultural catchments.
Inform Policy
The EUTROSED project (and in particular TCD contribution to the overall project) will help to identify the sources of P in four small agricultural catchments. Depending on what the outcome of the research is,this may lead to evidence-based advice for new policies (or further support of existing policies) in line with the Water Framework Directive, which aims to mitigate such sources / activities.
Develop Solutions
The EUTROSED project (and in particular TCD contribution to the overall project) will help to identify the sources of P in four small agricultural catchments. Depending on findings from the research with respect to the potential source of this form of P, potential solutions may be identified which could form the basis of future EPA targeted research projects.
Section B:Objectives and targets, detailed work-packages, risk and contingencies
This project endeavours to address the current lack of understanding with regards to which P fractions within fluvial and stream bed sediments are more bioavailable and therefore degrade water quality; with the focus specifically on the effect of organic P and humic-metal P complex pools from fluvial sediments. Concurrently, a predictive understanding of biogeochemical transformations and fluxes of fluvial and streambed sediment bound P will be developed which can then feed into predictive biogeochemical hydro-sedimentary models for catchment water quality. This lack of data currently represents a major obstacle to the design and implementation of integrated water resource management of agricultural river catchments. TCD’s contribution to this research - by the collection of sediment samples in different catchments under varying hydrological conditions, their analysis using novel techniques, controlled laboratory experiments and collaborative inputs into the development of numerical models - will contribute directly to all of the following objectives:
  • Delineate the role of fluvial sediments on the delivery of bioactive P from agricultural catchments to downstream aquatic and flood plain systems, with an emphasis on the macronutrient organic P.
  • Investigate the seasonal variation in inorganic (humic-metal P complexes) and organic P content (monoesters, di-esters, peptide, DNA etc.) in the fluvial suspended sediments between contrasting agricultural catchments.
  • Advance the mechanistic and predictive understanding of the biogeochemical interactions and fluxes between fluvial and streambed bound P, particularly in the context of agricultural-induced land use changes.
  • Identify likely sources of sediment associated organic P using radiometric finger-printing techniques to provide valuable information on organic P dynamics within agricultural catchments.
  • Examine organic P flux across trophic transition in agricultural river bed sediment (by a chronology study to detect where eutrophication may have been detected). This will enable organic P repositories to be identified and their rates of degradation to be quantified.
  • Examine seasonal, geomorphological and land-use effects on sediment bound organic P bio-availability for in-stream algal and weed vegetation growth in contrasting geological agricultural catchments.
  • Develop the modelling capabilities for interpreting and predicting the effects of low flow and episodic flood events on the export of suspended and streambed sediment bound bioactive P from agricultural catchments.
The work plan for the Irish partner is detailed in the Gantt chart. The proposed project will be divided into three main work packages, as set out in the Table below, each building upon the success of the other. Contingency plans will be inbuilt into each work packages to provide a safety net in case of anything going off course. The Irish lead partner has ample resources to complete all tasks within the time frame allotted within the timeline for the project as outlined in the Gantt Chart. The administrative management of the project will be coordinated by the Principal Investigator, Laurence Gill at TCD. The person-months allocated to each task are appropriate in order for completion of the goals and objectives. Field sampling and analysis will be carried initially while concurrently isotope and predictive model development will overlap. This is necessary for amalgamation of field data to feed predictive model development and the time allowed is the minimum in developing ground-breaking predictive models.

Work Packages:

Work Package Title: / P Bioprocesses
Work Package No.: / WP1
Cost: / €115,806
Start Month: / 1 / End Month: / 24
Work Package Leader Details: / Leader Name / Leader Organisation / Leader Person Months
Laurence Gill / TCD / 1
Work Package Partner(s) Details: / Partner Name / Partner Organisation / Partner Person Months
1 / Research Fellow / TCD / 14
2
3
NB: insert additional rows above if required.
Objectives: /
  • Role of fluvial sediments on the delivery of bioactive P from agricultural catchments
  • Seasonal and spatial dynamics onthe inorganic and organic P content of fluvial sediments
  • Identify likely sources of sediment associated organic P and humic matter associated P using radiometric finger-printing technique
  • Examine organic P and humic P flux across trophic transition in agricultural river bed sediment
  • Examine seasonal, geomorphological and land-use effects on sediment bound organic P bio-availability for in-stream algal and weed vegetation growth in contrasting geological agricultural catchments

Description of Work: / Description of Work.
This work-package will focus onthe biogeochemical processes and properties of fluvial sediment bound organic phosphorus.Specifically, the effects of redox oscillations on P exchanges and speciation will be examined in the field and in laboratory incubations.
As such, the TCD postdoctoral researcher will select at least 4 catchments in Ireland with different land-use (arable and pasture) and different scales and geologies. These catchments will then be instrumented to collect data on flow dynamics, meteorological parameters and also collect samples of sediment. For this improved fluvial baffle sediment traps and sedimentation mats will be designed, and deployed.The collected sediment samples will then be subjected to a range of different analytical techniques as follows. A combined approach will be followed using nano-scale analytical techniques (electron microscopy, 31P NMR and synchrotron-based spectroscopy) along with chemical extractions to compare the solid-state speciation of P under stable and fluctuating redox conditions13. The 31P NMR spectroscopy will be carried out at TCD.
Sediment samples will also be sent to the Canadian Light Source (CLS) synchrotronfor P, C and N K-edge XANES analysis and the results will be very useful for interpreting the transformation of inorganic to organic P.
The bioavailability of suspended sediment and streambed bound organic P will be assessed directly in bioassays with algal cultures14and using enzymatic hydrolysis measurements15 min TCD. This work package will also involve hosting two Masters students from Canada to give them experience in catchment hydrology.
13Liu, J. et al. (2015). Environmental Science & Technology, 49, 168-176
14Peeterset al. (1991). Water Science and Technology, 24, 10, 261-267
15Giles, C.D. et al. (2015). Journal of Environmental Quality, 44, 882-897
Deliverables and Milestones: / M1.1Selection of 4 catchments of different land-use pressures and geology
D1.1Dataset of fractionated P content of fluvial solids from 4 Irish catchments.
D1.2 Two publications (led by TCD) in international journals
D1.3Training of 2 international Masters students (from Canada).
Expected Outcomes: /
  • development of suspended solids sampling field equipment
  • greater understanding on role of fluvial sediments on the delivery of bioactive P

Work Package Title: / Spectroscopy/ isotopes
Work Package No.: / WP2
Cost: / €74,235
Start Month: / 8 / End Month: / 24
Work Package Leader Details: / Leader Name / Leader Organisation / Leader Person Months
Laurence Gill / TCD / 0.5
Work Package Partner(s) Details: / Partner Name / Partner Organisation / Partner Person Months
1 / Research Fellow / TCD / 9
2
3
NB: insert additional rows above if required.
Objectives: /
  • Advance the mechanistic and predictive understanding of the biogeochemical interactions and fluxes between fluvial and streambed bound organic P and humic matter bound P
  • Examine organic P and humic P flux across trophic transition in agricultural river bed sediment
  • Examine seasonal, geomorphological and land-use effects on sediment bound organic P bio-availability for in-stream algal and weed vegetation growth in contrasting geological agricultural catchments

Description of Work: / Description of Work.
This work package will test the hypothesis that thestrong biogeochemical gradients and fluctuations within suspended and streambed sediments of geologically contrasting agricultural catchment streams result in phosphorus bio-availability dynamics. As per WP1, sediment samples from the rivers will be collected and subjected to the following analytical methods by the TCD team. Methods involving extra-cellular enzymatic hydrolysis will be used to identify and quantify the activity of organic P species specific enzymatic hydrolysis16within suspended sediments and in-stream sediment profiles. In addition, a relatively new isotopic approach, O18p suspended and streambed sediments, based on the tracing of the oxygen stable isotopes of phosphate will be applied to tracing phosphate sorbed to suspended sediments and within streambed sediments for the first time to give information on the sources of this sorbed phosphate within the agricultural catchment. This method will allow tracking of short-term transformations of readily bioavailable P to a less or non-bioavailable P pool (i.e. specific minerals or organic P species). These findings should demonstrate the usefulness of O18p as a tracer for P cycling within agricultural catchments which could be used for fertiliser and nutrient management tracing in the future.
16Wang et al. (2010). Ecological Engineering, 36, 7, 963-968.
Deliverables and Milestones: / D2.1 Adequate samples retrieved from Irish catchments for isotopic analysis.
D2.2 Dataset of isotopic P content of fluvial solids from Irish catchments.
D2.3 Two publications (1 led by TCD, 1 led by UoS) in international journals
Expected Outcomes: /
  • proof of the usefulness of of O18p as a tracer for P cycling
  • advanced spectroscopy training of the Research Fellow

Work Package Title: / Modelling
Work Package No.: / WP3
Cost: / €65,986
Start Month: / 16 / End Month: / 36
Work Package Leader Details: / Leader Name / Leader Organisation / Leader Person Months
Laurence Gill / TCD / 0.5
Work Package Partner(s) Details: / Partner Name / Partner Organisation / Partner Person Months
1 / Research Fellow / TCD / 8
2
3
NB: insert additional rows above if required.
Objectives: /
  • Develop the modelling capabilities for interpreting and predicting hydrological effects on the export of fluvial sediment bound bioactive P from agricultural catchments

Description of Work: / Description of Work.
This work package will address theregional scale impacts of biogeochemical transformations within suspended and streambed sediment bound phosphorus in geologically contrasting agricultural catchments.The experimental results from WP1 & WP2 will form the basis for refining and developing the mathematical formulations describing the suspended sediment exchanges of P (particularly organic P), so that the coupling of sediment transport and biogeochemical transformations can be better constrained in predictive P exchange models for agricultural catchments.
This work package will be carried out by the TCD research Fellow in collaboration with the Swedish consortium partner research group of Prof. Bishop (SLU). The Irish postdoctoral student will provide collated hydrological data for the modelling, as well as spending time in Sweden working with the model developers. The models will then be ran by the TCD Research Fellow to simulate different scenarios to assess the impact of different management strategies on the ecological status of the waters in agricultural landscapes as well as the loading to downstream environments as affected by P fluxes and bioavailability.
Deliverables and Milestones: / D3.1 Advanced biogeochemical hydro-sedimentary model for use as a predictive P exchange model for agricultural catchments.
D3.2 Range of predictive scenario results
D3.3 Two publications (1 led by TCD, 1 led by SLU) in international journals
Expected Outcomes: /
  • development of a predictive P exchange model for agricultural catchments (from SLU)
  • Range of predictive scenario results for discussion

Work Package Title: / Communication and Dissemination Activities
Work Package No.: / WP4
Cost: / €16496