Norwegian lakes show widespread recovery from acidification; results from national surveys of lakewater chemistry 1986-1997

摘要: Surveys of 485 lakes in Norway conducted 1986 and again 1995 reveal widespread chemical recovery from acidification. Sulphate concentrations have decreased by 40% acidified areas southern Norway. This decrease has been compensated about 25% decreases base cations 75% increased Acid Neutralising Capacity (ANC). The ANC turn reflects lower acidic Aluminum (AL n+ ) Hydrogen (H + ). A sub-set 78 the sampled yearly between 1997 shows that, at first most non-marine sulphate (SO 4 * was a cations, such that remained unchanged. Then as SO continued to decrease, non- marine calcium magnesium ((Ca+Mg) levelled out. Consequently, increased, H Al started decrease. In eastern Norway, this shift occurred 1989–90, came slightly later western Similar shifts trends 1991–92 can also be seen non-acidified central northern is not pronounced perhaps because confounding influence sea-salt episodes on water chemistry. documented national-scale acidification due reduced acid deposition. Future climate warming potentially N-leaching counteract positive