Sources of Alkalinity in Precambrian Shield Watersheds Under Natural Conditions and After Fire or Acidification

摘要: Analysis of 13 years chemical and hydrological records for three small watersheds in the Experimental Lakes Area north-western Ontario yielded following conclusions: 1. The did not export significant alkalinity even though precipitation area has been strongly acidic (long-term average = pH 4.9). Rates production terrestrial were a fraction those lakes. 2. Forest fires cause an increase yield watersheds. Instead, there was slight tendency to decrease fire due higher releases strong acid anions. This might have drought rather than per se. 3. Two experimental application sulphuric nitric acids wetland at roughly 10 times normal rates deposited from atmosphere caused little change acidity outflow wetland. Sulphate nitrate ions almost completely retained. 4. In upland catchments with shallow soils, biological retention sulphate, nitrate, ammonium affected balance more ion exchange geochemical weathering.