The response of dissolved organic carbon (DOC) and the ecosystem carbon balance to experimental drought in a temperate shrubland

摘要: Climate change has been proposed as a driver of carbon (C) loss from the large pool C held in soils. Aqueous (dissolved organic carbon, DOC) and gaseous (soil respiration or net ecosystem CO2 exchange) forms soils have considered. Under some climate scenarios, emissions predicted to result terrestrial ecosystems becoming source by 2050. Indeed, both linked climate-related changes, such warming and/or changes precipitation. In our field-based drought manipulation experiment on an upland moorland northeast Wales, we carried out annual treatment for 8 years, reducing levels rainfall 23% average (1999–2007) through use automated roofs, which prevent rain falling experimental plots between June September annually. Following 5 years repeated summer drought, there was 26% increase concentrations DOC soil water mineral this further increased 52% after years. A similar pattern not observed horizons. Despite higher horizon, decreased drainage drought-treated resulted overall decrease 9% total export. Calculating balance below-ground component reveals that represents 3% gross Previous studies at site demonstrated increases resulting treatment. By including data presented here with other fluxes measurements site, demonstrate is accumulating 126 g m−2 year−1 control plots, but decreasing 18 m2 plots. The thus switching sink into source.