The Multi-Scale Response of Water Quality, Biodiversity and C Sequestration to Coupled Macronutrient Cycling from Source to Sea

流域研究传统上侧重于水流和质量的科学和管理。近年来，实现良好的生态状况并遵守水框架指令已成为当务之急。这一直是一个挑战，尤其是因为英国的大多数河流都受到氮、磷的严重污染，并且包括病原体在内的一系列污染物以及来自高地地区的溶解有机碳的转移正在增加。这些可能损害河流和沿海水域的生态，对人类健康构成风险，并增加水工业的成本。继国家生态系统评估（2011年）和政府自然环境白皮书（2011年）发布之后，流域管理者面临着更大的挑战，试图确保水资源目标不会影响其他功能的实现，这些功能提供一系列我们都从中受益的调节、供应或文化服务。这些生态系统服务的基础是基本的生态系统过程，例如植物的碳固定和通过分解（碳循环）将碳返回大气、氮和磷等营养物质通过植物、土壤、水和大气的循环以及包括病原体在内的一系列污染物的解毒。关于单个碳、氮和磷（C、N 和 P）以及污染物循环，人们已经了解很多，但是，这些循环在景观中的耦合以及随后对自然环境和所提供的服务的影响却很少被研究。为了回应我们目前理解中的这一差距，我们将解决两个研究问题。第一个问题是耦合常量营养素循环（C、N 和 P）何时、何地以及如何影响流域尺度景观单元内部和之间自然环境的功能？第二个问题是，这些耦合循环在土地利用、空气污染和气候变化的情况下将如何变化，以及对流域和国家规模的水质、碳封存和生物多样性（三个重要的生态系统服务）有何影响？为了实现这一目标，我们将通过关键过程（净初级生产力、分解、养分循环）来量化碳、氮和磷循环的通量、转化和耦合，并结合康威流域的有针对性的现场监测以及基于现场和实验室的实验，并辅以里布尔集约化养殖地区的测量，来量化与病原体转移和活力的联系。预计取得以下成果： 1．对跨土壤功能类型和处理热点内的耦合 C、N 和 P 过程、转化和通量进行量化和改进过程理解。 2. 河道内生态系统功能和N/P共同限制对淡水富营养化发展影响的量化。3．检验以下假设：陆地和淡水生物多样性可以在流域和国家范围内解释为常量营养素通量和初级生产力的函数。4．海洋通量量化的来源和病原体命运的过程理解以及非常细的沉积物（絮凝物）中常量营养素所施加的控制。 5. 一个集成的、简约的耦合大量营养素（C、N、P）空气-陆地-水建模平台，配置为横跨康威的 1 公里网格（即增强的 JULES 模型）。6。碳汇、水质和生物多样性对过去和未来气候、养分和土地（森林）覆盖变化的敏感性分析，确定过去和未来碳汇、水质和生物多样性变化的关键控制措施。7．流域规模碳封存、水质和生物多样性的权衡以及与土地覆盖类型和气候状况的关系的量化。

Catchment research has traditionally been focussed on the science and management of water flow and quality. In recent years, achieving good ecological status and compliance with the Water Framework Directive has been a priority. This has been challenging not least because the majority of rivers in the UK are heavily polluted with nitrogen, phosphorus, and a range of contaminants including pathogens and transfers of dissolved organic C from upland areas are increasing. These can be detrimental to the ecology of rivers and coastal waters, be a risk for human health and increases costs of the water industry. Following the publication of the National Ecosystem Assessment (2011) and the Government's White Paper on the Natural Environment (2011), catchment managers face an even greater challenge trying to ensure water resource objectives do not compromise delivery of other functions which deliver a range of regulating, provisioning or cultural services which we all benefit from. Underpinning delivery of these ecosystem services are basic ecosystem processes such as carbon fixation by plants and the return of carbon back to the atmosphere through decomposition (the carbon cycle), the cycling of nutrients such as nitrogen and phosphorus through plants, soil, water and the atmosphere and detoxification of a range of contaminants including pathogens. Much is known concerning the individual carbon, nitrogen and phosphorus (C, N and P) and contaminant cycles, however the coupling of these cycles through the landscape and the subsequent impacts on the natural environment and the services provided are rarely studied. To respond to this gap in our current understanding we will address two research questions. The first is when, where and how do coupled macronutrient cycles (of C, N and P) affect the the functioning of the natural environment within and between landscape units at the catchment scale? The second is how will these coupled cycles alter under land use, air pollution, and climate-change and what will be the effect on water quality, carbon sequestration and biodiversity (three important ecosyststem services) at both catchment and national scale? To achieve this, we will quantify the fluxes, transformations and coupling of the C, N, and P cycles through key processes (net primary productivity, decomposition, nutrient cycling) and quantify the links to pathogen transfer and viability using a combination of targeted field-based monitoring and field- and laboratory-based experimentation in the Conwy catchment supplemented by measurements in intensively farmed areas of the Ribble. The following outcomes are expected:1. Quantification and improved process-understanding of coupled C, N and P processes, transformations and fluxes across soil functional types and within processing hotspots. 2. Quantification of the effects of instream ecosystem function and co-limitation of N/P on eutrophication development in freshwaters.3. Testing of hypotheses that terrestrial and freshwater biodiversity can be explained at the catchment- and national-scales as function of macronutrient flux and primary productivity.4. Source to sea flux quantification and process-understanding of the fate of pathogens and the controls exerted by macronutrients within very fine sediments (flocs). 5. An integrated, parsimonious coupled macronutrient (C, N, P) air-land-water modelling platform, configured for a 1 km grid across the Conwy (i.e. an enhanced JULES model).6. Sensitivity analysis of carbon sequestration, water quality and biodiversity to past and future climate, nutrient and land (forest) cover change to determine the key controls on past and future changes in carbon sequestration, water quality and biodiversity.7. Quantification of trade offs in delivery of carbon sequestration, water quality and biodiversity at the catchment scale and the relationship to land cover type and climate regime.