Decadal-scale dynamics of water, carbon and nitrogen in a California chaparral ecosystem: DAYCENT modeling results
Li, XY; Meixner, T; Sickman, JO; Miller, AE; Schimel, JP; Melack, JM
| HERO ID | 1686845 |
|---|---|
| In Press | No |
| Year | 2006 |
| Title | Decadal-scale dynamics of water, carbon and nitrogen in a California chaparral ecosystem: DAYCENT modeling results |
| Authors | Li, XY; Meixner, T; Sickman, JO; Miller, AE; Schimel, JP; Melack, JM |
| Journal | Biogeochemistry |
| Volume | 77 |
| Issue | 2 |
| Page Numbers | 217-245 |
| Abstract | The Mediterranean climate, with its characteristic of dry summers and wet winters, influences the hydrologic and microbial processes that control carbon ( C) and nitrogen (N) biogeochemical processes in chaparral ecosystems. These biogeochemical processes in turn determine N cycling under chronic N deposition. In order to examine connections between climate and N dynamics, we quantified decadal-scale water, C and N states and fluxes at annual, monthly and daily time steps for a California chaparral ecosystem in the Sierra Nevada using the DAYCENT model. The daily output simulations of net mineralization, stream flow and stream nitrate (NO3-) export were developed for DAYCENT in order to simulate the N dynamics most appropriate for the abrupt rewetting events characteristic of Mediterranean chaparral ecosystems. Overall, the magnitude of annual modeled net N mineralization, soil and plant biomass C and N, nitrate export and gaseous N emission agreed with those of observations. Gaseous N emission was a major N loss pathway in chaparral ecosystems, in which nitric oxide ( NO) is the dominant species. The modeled C and N fluxes of net primary production (NPP), N uptake and N mineralization, NO3- export and gaseous N emission showed both high inter-annual and intraannual variability. Our simulations also showed dramatic fire effects on NPP, N uptake, N mineralization and gaseous N emission for three years of post. re. The decease in simulated soil organic C and N storages was not dramatic, but lasted a longer time. For the seasonal pattern, the predicted C and N. uxes were greatest during December to March, and lowest in the summer. The model predictions suggested that an increase in the N deposition rate would increase N losses through gaseous N emission and stream N export in the chaparral ecosystems of the Sierra Nevada due to changes in N saturation status. The model predictions could not capture stream NO3- export during most rewetting events suggesting that a dry-rewetting mechanism representing the increase in N mineralization following soil wetting needs to be incorporated into biogeochemical models of semi-arid ecosystems. |
| Doi | 10.1007/s10533-005-1391-z |
| Wosid | WOS:000235449500005 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Source: Web of Science WOS:000235449500005 |
| Is Public | Yes |
| Keyword | carbon and nitrogen cycling; chaparral ecosystem; DAYCENT; drying-rewetting pulse; fire disturbance; Mediterranean-climate; nitrogen deposition |