Steven S. Perakis Gaius R. Shaver Goran I. Agren Edward B. Rastetter 2005 <p><span>We used a simple model of carbon–nitrogen (C–N) interactions in terrestrial ecosystems to examine the responses to elevated CO</span>₂<span><span>&nbsp;</span>and to elevated CO</span>₂<span><span>&nbsp;</span>plus warming in ecosystems that had the same total nitrogen loss but that differed in the ratio of dissolved organic nitrogen (DON) to dissolved inorganic nitrogen (DIN) loss. We postulate that DIN losses can be curtailed by higher N demand in response to elevated CO</span>₂<span>, but that DON losses cannot. We also examined simulations in which DON losses were held constant, were proportional to the amount of soil organic matter, were proportional to the soil C:N ratio, or were proportional to the rate of decomposition. We found that the mode of N loss made little difference to the short‐term (&lt;60 years) rate of carbon sequestration by the ecosystem, but high DON losses resulted in much lower carbon sequestration in the long term than did low DON losses. In the short term, C sequestration was fueled by an internal redistribution of N from soils to vegetation and by increases in the C:N ratio of soils and vegetation. This sequestration was about three times larger with elevated CO</span>₂<span><span>&nbsp;</span>and warming than with elevated CO</span>₂<span><span>&nbsp;</span>alone. After year 60, C sequestration was fueled by a net accumulation of N in the ecosystem, and the rate of sequestration was about the same with elevated CO</span>₂<span><span>&nbsp;</span>and warming as with elevated CO</span>₂<span>alone. With high DON losses, the ecosystem either sequestered C slowly after year 60 (when DON losses were constant or proportional to soil organic matter) or lost C (when DON losses were proportional to the soil C:N ratio or to decomposition). We conclude that changes in long‐term C sequestration depend not only on the magnitude of N losses, but also on the form of those losses.</span></p> application/pdf 10.1890/03-5303 en Ecological Society of America Terrestrial C sequestration at elevated CO2 and temperature: the role of dissolved organic N loss article