Dissolved organic carbon in New Zealand peatlands

We determined the concentration of dissolved organic carbon (DOC) and the specific ultraviolet absorbance (SUVA) of 193 samples of water collected from groundwater, porewater, drainage ditches, and streams at peatlands in New Zealand. There was a wide range in DOC concentration (from 7 to 184 mg litre(-1)), with the smallest concentrations in peatlands where there appeared to be large amounts of iron. Concentrations were large (generally > 50 mg litre(-1)) in ombrotrophic (rain-fed) peatlands and reached the highest values (averaging 81 to 129 mg litre(-1)) in water collected from the Torehape peatland (Waikato region) , which is undergoing drainage and harvesting for peat and post-harvest restoration. These high DOC concentrations suggest that New Zealand peatlands export 10 to 50g DOC m(-2) yr(-1), a significant part of the overall carbon budget of peatlands. Most SUVA measurements ranged from 1.5 to 3.5 litre/mg DOC-1/m(-1)) and suggest that the DOC contains 12 to 25% aromatics.