A multisite analysis of the role of high flow extremes on aquatic DOC export

The release of soil derived DOC into river systems is a major C transport pathway in many upland catchments, particularly where organic-rich soils dominate. Aquatic C export (of which DOC is the primary component) represents 30-50% of C uptake via NEE in peatland catchments. Both soil-stream transport and downstream export of DOC are highly sensitive to changes in hydrological regime and are therefore greatly influenced by climatic extremes such as storm flow and snow melt. Here we utilise long-term DOC datasets from 8 UK streams provided by the ‘Environmental Change Network’ (ECN), alongside long-term datasets from 6 Swedish streams, to investigate the relative contribution of storm flow events to total annual DOC export. We consider seasonality in the contribution of high flow events to total DOC export, and compare the storm flow responses across catchments considering catchment characteristics such as vegetation community, soil type and hydrological regime. Finally, by combining the information gained in the aforementioned analysis we will consider how DOC export is likely to respond to predicted changes in regional precipitation patterns.