Peatlands are one of the largest terrestrial carbon stores and have persisted across the globe for millennia. They function globally as long-term sinks of atmospheric carbon dioxide and regionally as watershed sinks of toxic metals. Therefore, peatland ecosystems play a critical role in both global climate regulation and source water protection and, as such, their conservation, management and restoration have been identified as a key activity to meet the UN Sustainable Development Goals. Human activity has contaminated peatlands over many centuries through the atmospheric deposition of pollutants released by industrial processes (e.g., manufacturing, resource extraction). Evidence of this can be found in peatlands around the world and peat core records show pronounced pollution signals associated with the Roman period in Europe, the Industrial Revolution of the 18th and 19th centuries, and widespread use of leaded petrol in the 20th century. High rates of metal pollution can lead to the degradation of peatland processes that sustain critical ecosystem functions, such as carbon sequestration. Once damaged, these peatlands become very susceptible to additional disturbances such as fire or drainage, which can release their toxic legacy into the environment and drinking water. Release of these previously sequestered metals arguably represents one of the major contemporary global environmental challenges of the 21st century, yet this is an understudied research field and is poorly understood outside specialist areas. In this project, we will address this knowledge gap by building an interdisciplinary, international partnership, facilitated by a core group of researchers with complementary skills and expertise. Through project meetings and field visits, we will foster a collaborative environment to share insights and knowledge to produce an agenda-setting academic paper. We will create wider international community engagement through online workshops and webinars. The findings from the project will contribute to broader debates about how to best preserve and restore contaminated peatlands in order to provide resilience in the face of future climate and land use change.

Boreal regions hold upwards of 60% of the planet's freshwater, an essential ingredient for all life. But human activities, such as climate and land use change, are dramatically altering these landscapes and threatening the delivery of key services provided by aquatic ecosystems, such as clean drinking water and healthy fish populations. Contemporary paradigms of aquatic conservation have emphasized inputs of pollutants and water resource development as causes of declining water security and biodiversity, but restoration attempts are failing when these two factors alone are improved. Increasingly, local watersheds are seen as critical controls of aquatic ecosystems. This is spurred by the recent discovery that pathways of energy mobilization upwards through aquatic food webs - from microbes to fish - rely on organic matter originating from terrestrial vegetation, proving the adage that "clean water is a forest product". Any factor that changes the quality and quantity of organic matter input into freshwater from their surrounding catchments will clearly influence the delivery of aquatic ecosystem services. Fire, forest pests, and resource development, such as mining and logging, are emerging disturbances that are transforming boreal regions, but little is known as to how they will change long-term cycling of nutrients from terrestrial vegetation into aquatic ecosystems. A new watershed-level science that integrates the management of forestry and water resources is clearly needed to inform decision makers of the actions needed to conserve freshwater supplies by linking actions on land to processes in water. Our research will test whether the productivity of aquatic food webs increases with the quantity and quality of terrestrial organic matter under different climate scenarios. We will also answer whether disturbances on land that remove plant biomass and change the quality of plant litter will dampen the productivity of freshwater plants and animals. Our approach will be to create 96 artificial ecosystems in a common lake environment and expose sites to different quantities and qualities of organic matter. We will measure the responses of microbial, algal, and grazer communities using cutting-edge technologies such as next-generation DNA sequencing. We will also plant tagged individuals of a sedentary mussel species closely-related to economically important taxa within each site and monitor their long-term growth and survival. The ultimate goal of this work is to develop a spatially-explicit, dynamical watershed-level simulation model. We want to answer the question if X% of habitat is consumed by fire or insect outbreaks, then food stocks for fish will change by Y%. Outcomes of this research will be highly relevant to the UK and international policy around managing freshwater supplies by demonstrating strong linkages between terrestrial and aquatic ecosystems. For example, the EU has developed legislation to protect freshwater but this ignores the effects of land use practices on lake water quality and biota. The future of extensive forestry plantations and pastures surrounding many socio-economically important watersheds in Britain are also being debated as the EU begins reforming the Common Agricultural Policy. We aim to show that any changes in land use must consider how energy in the form of organic matter is dispersed to aquatic ecosystems and supports their productivity. Finally, this project will have many applications for improving regional land use planning and management, as well as restoring environmentally damaged landscapes. We will work closely with partners in the mining industry and government to inform them of the best practices for re-vegetating degraded watersheds.