The role of lateral exchange in modulating the seaward flux of CNP

Lead Research Organisation: University of Essex
Department Name: Biological Sciences


All living organisms that make up life on Earth are made from a profusion of elements in the periodic table, including trace metals. However, in addition to oxygen (O) and hydrogen (H), the constituents of water, the three most important are Carbon (C), Nitrogen (N) and Phosphorus (P). These have become known as the Macro-Nutrients. These macronutrients are in constant circulation between living organisms (microbes, plants, animals, us) and the environment (atmosphere, land, rivers, oceans). Until human intervention (circa post industrial revolution and even more so since WWII) these 'cycles' were largely in balance: plants took up CO2 and produced O2 and, in order to do so, took up limited amounts of N and P from the environment (soils, rivers) and, on death, this "sequestered" C,N,P was returned back to the Earth. The problem is that human or anthropogenic activity has put these key macro-nutrient cycles out of balance. For example, vast quantities of once fossilised carbon, taken out of the atmosphere before the age of the dinosaurs, are being burnt in our power stations and this has increased atmospheric CO2 by about 30 % in recent times. More alarmingly, perhaps, is that man's industrial efforts have more than doubled the amount of N available to fertilize plants, and vast amounts of P are also released through fertilizer applications and via sewage. As the population continues to grow, and the developing world catches up, and most likely overtakes, the western world, these imbalances in the macro-nutrient cycles are set to be exacerbated. Indeed, such is the impact of man's activity on Earth that some are calling this the 'Anthropocene': Geology's new age. The environmental and social problems associated with these imbalances are diverse and complex; most people would be familiar with the ideas behind global warming and CO2 but fewer may appreciate the links to methane and nitrous oxide or the potential health impacts of excess nitrate in our drinking water. These imbalances are not being ignored and indeed a great deal of science, policy and management has been expended to mitigate the impacts of these imbalances. However, despite our progress in the science underpinning this understanding over the last 30-40 years or so, too much of this science has been focused on the individual macro-nutrients e.g. N, and in isolated parts of the landscape e.g. rivers. To compound this even further, such knowledge and understanding has often been garnered using disparate, or sometimes even antiquated, techniques. Anthropogenic activity has spread this macro-nutrient pollution all over the landscape. Some of it is taken up by life, some is stored, but a good deal of it works its way through the landscape towards our already threatened seas. We need to understand what happens to the macronutrients as they move, or flux, through different parts of the landscape and such understanding can only come about by a truly integrated science programme which examines the fate of the macronutrients simultaneously in different parts of the landscape. Here we will for the first time make parallel measurements, using truly state-of-the-art technologies, of the cycling and flux of all three macronutrients on the land and in the rivers that that land drains and, most importantly, the movement of water that transports the macro-nutrients from the land to the rivers e.g. the hydrology. Moreover, we will compare these parallel measurements across land to river in different types of landscapes: clay, sandstone and chalk, subjected to different agricultural usage in order to understand how the cycling on the land is connected, via the movement of water, to that in the rivers.

Planned Impact

Who will benefit? This blue skies research will quantify the flux and dynamics of the lateral exchange of organic C through the Avon catchment & how this in turn modulates the scale of flux, & nature of N & P transformations, towards the coast. There are several end-users & beneficiaries in both private & public sectors e.g. Defra, Environment Agency (EA), CEFAS, Wessex Water, wastewater companies, Local Authorities, agricultural & farming sectors. Learning how catchment changes directly influence C,N,P cycles will enable these organisations to save resources by targeting their actions on those aspects of the nutrient cycles that have the greatest benefit. The project also benefits academics & the public.
How will they benefit? The project enhances quality of life, health & environment as follows:
1. Data on N & P transformations under perturbed C cycles will inform Defra's policies on the impact of nutrient pollution on the environment (e.g. Nitrates Directive, Water Framework Directive, National Emissions Ceilings Directive).
2. Data on the spatial & temporal scales of P, NH4+, NO3- transformations, the timescales for nutrient transport through the catchment & whether interactions with P increase DN will inform Defra's strategy on N2O emissions & the interactions between N2O & other forms of N (& P) enabling improved mitigation strategies to be developed for reducing both pollution & greenhouse gas emissions (Low C Transition Plan, Climate Change Act)
3. Data on air to soil exchange of CO2 (& CH4) under increased temperatures & perturbed C cycle in the catchment will inform Defra's policy on mitigating climate change by reducing CH4 emissions and improve environmental air quality.
4. Data on the lateral exchange of organic C through the catchment will also determe the potential cycles & sinks for C in other water bodies. For e.g., there is significant policy interest in Defra on C fluxes within water column to benthic sediments (e.g. Cefas) via the Marine Strategy Framework which manages sustainable marine resources.
5. Data on how elevated temperatures effects microbial diversity will inform how climate change impacts on microbial biodiversity.
6. Data on fecal indicator organisms (FIO) will inform FIO mitigation by improved agricultural management.
The project increases the effectiveness of public services & policy as follows:
1. Data generated will test & parameterise a model, which can be used by Defra's UKCIP to more accurately predict potential cycles & sinks for C under future climate scenarios, helping Local Authorities (e.g. Hampshire County Council) adapt to climate change.
2. The project gives added value to Defra's Demonstration Test Catchments (DTC) monitoring program with additional nutrient data from sites within the catchment not currently monitored by Defra and will give important information on how different agricultural management practices influence scale of flux of C,N, P cycling in the catchment.
3. Data on C, N & P flux through river food webs will inform Defra's policy on biodiversity & information on how diffuse pollution & N impacts biodiversity decline.
4. Data obtained will inform EA policy of Urban Wastewater Treatment Directive, Habitats Directive & Marine Environment.
5.Data will inform policy on C sequestration & UK C inventories & help to meet the Government's goals for protecting & sustaining natural resources.
Production of trained staff: The project will produce 4 trained PhD students & 9 PDRAs with molecular, analytical, hydrology, ecology and modelling skills who can enter private/public sector marketplace.
Economic benefits: IP resulting from the project will foster industrial collaborators and enhance economic competitiveness of UK.
Timescales for benefits to be realized: The SAG set up in month 1 with representatives from stakeholders, regulators & policymakers (see pathways to impact) will inform the project throughout to ensure policy aims are realised.
Description 1. Annual measurements of N transformation processes (mineralization, nitrification, denitrification and nitrous oxide production) have been performed for a seasonal cycle (Aug 2013 to May 2014) at three terrestrial sites: Clay, Greensand and Chalk.

2. We have measured the effect of temperature on denitrification, nitrous oxide, mineralization, nitrification and N2O:N2 ratio on soils from the three sites: Clay, Greensand and Chalk.

3. Dentitrification genes (nirS & nirK) and microbial biomass (16S rRNA gene) have been determined across the Hampshire-Avon catchment.

4. amoA gene abundance from AOA & AOB have been determined across the catchment over a whole seasonal cycle. Illumina MiSeq 16S rRNA amplicon library have been completed for all sediment samples over a seasonal cycle in 9 rivers.

5. We have completed SIP (Stable Isotope Probing) incubations of soils and sediments with 13CO2 under both ambient-NH4 and NH4-enriched conditions.

6. We have measured soil and sediment CH4 production and oxidation and performed Q-PCR of the mcrA and pmoA genes throughout a seasonal cycle.
Exploitation Route Data from the process measurements and molecular microbial data can be inputted into models developed as part of the macronutrient programme.
Sectors Agriculture, Food and Drink,Environment

Description Our findings will enable end users e.g. involved in agriculture, Environment Agency, Water Companies and DEFRA to better manage agricultural practices on a catchment wide scale.
First Year Of Impact 2014
Sector Agriculture, Food and Drink,Environment
Impact Types Societal,Economic