HR: 13:55h
AN: B43F-02    [Abstracts]
TI: Hydrologic Variability and its Influence on Peatland Dynamics
AU: * Rennermalm, A K
EM: arennerm@princeton.edu
AF: Princeton University, Department of Civil and Environmental Engineering, Equad, Princeton University, Princeton, NJ 08544, United States
AU: Nordbotten, J M
EM: jnordbot@princeton.edu
AF: Princeton University, Department of Civil and Environmental Engineering, Equad, Princeton University, Princeton, NJ 08544, United States
AU: Nordbotten, J M
EM: jnordbot@princeton.edu
AF: University of Bergen, Department of Mathematics, University of Bergen, Bergen, N- 5020, Norway
AU: Wood, E F
EM: efwood@princeton.edu
AF: Princeton University, Department of Civil and Environmental Engineering, Equad, Princeton University, Princeton, NJ 08544, United States
AB: The present and future state of peatland carbon exchange depends on the climate sensitivity of peat accumulation and peat depletion processes. The climate sensitivity of these processes has been addressed by a range of studies that in general have focused on short time spans relative to peat processes. Long-term peat dynamic modeling studies suggest that peatlands can exist in bi-stable states; one having thin peat and deep water tables while the other has thick peat and shallow water tables. The climate sensitivity of peat accumulation and depletion inherent in bi-stable peatlands is not well understood or characterized. The bi-stability of peatland implies that gradual climate change and climate fluctuations may induce shifts between the two states. Such shifts may have long lasting impact on the peatland carbon exchange. The existence of peatland bi-stability in nature is indicated by the co-existence of fens and bogs across the northern hemisphere, and by the co-existence peatland hummocks and hollows. This presentation explores how precipitation variability affects peatland thickness, and peatland accumulation and depletion processes inherent in bi-stable peatlands. The results are based on a coupled peat accumulation/depletion hydrology model where precipitation/water availability is a stochastic forcing variable. While, the model is calibrated to represent the West Siberian Lowlands (WSL), our findings are applicable elsewhere as previous work shows that peatland bi-stability is possible across a wide range of climates. Model results for current climate conditions show that peatlands at steady state cycle through extended periods of peat accumulation and depletion. Therefore, observational studies limited to a few years are insufficient to detect fundamental changes in peatland carbon exchange due to climate change. For a drier and more variable future climate, results suggest that bi-stability (thin and thick peat states) will transition to a single steady state towards a new, more homogenous state with intermediate peat thickness. The transition may have profound and long lasting impact on the peatland carbon exchange, with some locations sequesting carbon while other areas losing carbon.
DE: 0428 Carbon cycling (4806)
DE: 0429 Climate dynamics (1620)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0497 Wetlands (1890)
DE: 1813 Eco-hydrology
SC: Biogeosciences [B]
MN: 2007 Fall Meeting