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THE ROLE OF WATER LEVEL FLUCUATION ON GHG DYNAMICS IN A TEMPERATE UK RESERVOIR (E)

Inland waters play an important role in the transport, transformation, loss and storage of carbon (C) in the pathway between terrestrial and marine systems. Reservoirs in particular are likely to represent biogeochemical cycling hotspots, and a potential source of greenhouse gases (GHGs) to the atmosphere due to large inputs of terrestrial carbon alongside operational and mixing processes. Many reservoirs undergo drawdown seasonally or for operational maintenance. Increased ebullition rates due to changes in hydrostatic pressure with water level are likely and drawdown exposes previously submerged littoral sediment to aerobic conditions. Vegetation which re-colonises this zone may provide a significant labile C input on rewetting. As these processes can act to convert atmospheric CO2 to the more potent GHG CH4, this zone may contribute disproportionately to emissions from the system as a whole. Whilst many studies focus on the magnitude of reservoir emissions, we still lack a clear picture of the internal controls on GHG production within the complex reservoir system. Here we report on a year of weekly-to-fortnightly measurements from a Scottish reservoir, focussing on the three-month drawdown period. During drawdown and rewetting, fluxes at the sediment-atmosphere interface were measured using static and soil respiration chambers, with water-table, water chemistry and sediment nutrient concentrations analysed to investigate the drivers of measured fluxes. Emissions during the drawdown period are put in context by comparing fluxes across the full year C budget.

Authors

McDonald, R. K., Centre for Ecology & Hydrology, United Kingdom, rosdon23@ceh.ac.uk

Dinsmore, K. J., Centre for Ecology & Hydrology, United Kingdom, kjdi@ceh.ac.uk

Billett, M. F., University of Stirling, United Kingdom, m.f.billett@stir.ac.uk

Skiba, U., Centre for Ecology & Hydrology, United Kingdom, ums@ceh.ac.uk

Evans, C. D., Centre for Ecology & Hydrology, United Kingdom, cev@ceh.ac.uk

Waldron, S., University of Glasgow, United Kingdom, susan.waldron@glasgow.ac.uk

Details

Oral presentation

Session #:001
Date: 03/03/2017
Time: 15:00
Location: 306 A

Presentation is given by student: Yes