Greenhouse Gas Instrumentation System for Aquatic Ecosystems (GHG-Aqua)

Land-use and agriculture are responsible for around one quarter of all human greenhouse gas (GHG) emissions. While some of the activities that contribute to these emissions, such as deforestation, are readily observable, others are not. It is now recognised that freshwater ecosystems are active components of the global carbon cycle; rivers and lakes process the organic matter and nutrients they receive from their catchments, emit carbon dioxide (CO2) and methane to the atmosphere, sequester CO2 through aquatic primary production, and bury carbon in their sediments. Human activities such as nutrient and organic matter pollution from agriculture and urban wastewater, modification of drainage networks, and the widespread creation of new water bodies, from farm ponds to hydro-electric and water supply reservoirs, have greatly modified natural aquatic biogeochemical processes. In some inland waters, this has led to large GHG emissions to the atmosphere. However these emissions are highly variable in time and space, occur via a range of pathways, and are consequently exceptionally hard to measure on the temporal and spatial scales required. Advances in technology, including high-frequency monitoring systems, autonomous boat-mounted sensors and novel, low-cost automated systems that can be operated remotely across multiple locations, now offer the potential to capture these important but poorly understood emissions.

In the GHG-Aqua project we will establish an integrated, UK-wide system for measuring aquatic GHG emissions, combining a core of highly instrumented 'Sentinel' sites with a distributed, community-run network of low-cost sensor systems deployed across UK inland waters to measure emissions from rivers, lakes, ponds, canals and reservoirs across gradients of human disturbance. A mobile instrument suite will enable detailed campaign-based assessment of vertical and spatial variations in fluxes and underlying processes. This globally unique and highly integrated measurement system will transform our capability to quantify aquatic GHG emissions from inland waters. With the support of a large community of researchers it will help to make the UK a world-leader in the field, and will facilitate future national and international scientific research to understand the role of natural and constructed waterbodies as active zones of carbon cycling, and sources and sinks for GHGs. We will work with government to include these fluxes in the UK's national emissions inventory; with the water industry to support their operational climate change mitigation targets; and with charities, agencies and others engaged in protecting and restoring freshwater environments to ensure that the climate change mitigation benefits of their activities can be captured, reported and sustained through effectively targeted investment.