Upscaling of greenhouse gas emissions from freshwater wetlands

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The single most important global environmental and policy concern in the 21st century is that of human-induced climate change, with an urgent need for quantitative information about the sources and sinks of the responsible greenhouse gases (GHGs); indeed, the international agreements from the 2015 Paris climate conference (COP21) emphasised the need for "the best available science" to aid in reducing atmospheric GHG growth rates. Unfortunately, there are serious gaps in our quantification of some major global natural sources and sinks of GHGs, and northern lakes and wetlands represent one such on-going debate. These limitations to our knowledge are largely a reflection of the necessary technologies for making the measurements. The two basic methods for quantifying GHG fluxes are called 'chamber' and 'eddy covariance (EC)' flux techniques; the former is a well-established technology which involves placing a small chamber over a land or water area and monitoring the gas concentration changes inside the chamber over time. The second, EC approach, relies upon summating small concentration differences in upward and downward air gusts (eddies) to derive a net system flux. Both systems Have their failings and advantages; for example, chamber systems only measure over small areas and are expensive to build and operate, whilst EC systems can provide a flux for a large area (km2) but cannot resolve down to locate point sources at the 'hotspot' or experimental plot scale. Under recent NERC funding, scientists at York have developed a totally new measurement approach, based on the technique used to move overhead cameras at major sports events. The system can rapidly place a chamber, or piece of heavy equipment, anywhere in a large measurement arena, to an accuracy of a few mms, achieved using precision-controlled winches, under the automatic control of a pre-programmed computer, and working continuously. The system can therefore provide highly replicated measurements in time and space, overcoming many of the problems of existing methods. The current grant is targeted at establishing such a system at one of the leading, and best equipped, GHG monitoring sites in the world (Lake Foljesjon, Sweden), where there are major unresolved questions about the key sources of the large GHG fluxes coming from this inland lake. The UK team have been invited to work collaboratively at the site because of the inherent difficulties of working in this terrain. The resulting international team will measure detailed GHG exchanges from the lake, identifying whether specific vegetation types, open water, specific sediment types etc. are the major hotspots for the observed gases fluxes (e.g. methane). Our roving equipment will work day and night, under all weather conditions, and will be unique throughout the world supported by full access to the existing sophisticated infra-structure (e.g. 3 phase electricity at the site, field accommodation and vehicles, local engineering support, access to existing datasets) as well as state-of-the-art sensors (e.g multi-spectral scanners, precision lasers) for test 'flying' on the head of our novel system, enabling unprecedented and accurate data about the structure of the lake and it's vegetation. If we successfully prove the technology in this difficult environment then similar systems could well be adopted around the world (e.g volcanos, agricultural research) leading to entirely new, UK-based, environmental monitoring technology and expertise. The International Opportunities Fund (IOF) scheme is designed to enable NERC-supported researchers to build long-term partnerships with overseas scientists, add value to current NERC-funded science; this is precisely the aim of the current work, with the resulting collaboration addressing a key global question neither group can answer alone, and initiating a potentially long-lived dovetailing of two highly complementary research groups.