We use six years of climate records (2006-2012) and near-continuous eddy covariance CO2measurements at the peatland study site, Bog Lake Fen, located within Marcell Experimental Forest, northern Minnesota, to investigate how extreme climate events impact the carbon cycle. Even now climate records have shown an increase in both temperature and precipitation compared to the 30-year average. Extreme climate events (i.e. drought, heavy rains, elevated air temperatures, earlier onset of frost-free period) have also become more common. Over the six-year period, annual precipitation totals varied widely (212 mm – 685 mm) with multiple precipitation events measuring 20 mm or greater in a 30-minute period. Water table position varied over 50 cm while average annual air temperature varied by more than 5°C.
Carbon cycle response show that maximum ecosystem respiration (ER) rates changed considerably between minimum (i.e. drought) and maximum precipitation years with ER varying by more than 140%. Extreme air temperatures along with other climate factors impacted the timing of maximum net ecosystem exchange (NEE) showing a difference of more than 50 days between annual periods. The lowest recorded water table position over the six-year period coincided with the lowest NEE or a >30% reduction compared to other annual periods. Already the effects of extreme events can be seen on the peatland. Further comparison between long-term versus short-term “events” and more severe versus less severe “events” will also provide insight to the potential long-term impacts to the peatland system.
Preferred Presentation Type: Oral