LAND-USE CHANGE AND LAKE ACIDIFICATION - IRON-AGE DE-SETTLEMENT IN NORTHERN SWEDEN AS A PREINDUSTRIAL ANALOG

Pollen analyses were used to identify vegetational change associated with a de-settlement period ca. 500 A.D. and diatom analyses to assess if there was any associated change in lake-water pH. A clear settlement horizon was found in the two lakes studied, indicating catchment disturbance associated with Iron Age agriculture. There was no change, however, in diatom reconstructed pH after de-settlement, during vegetation regeneration, when it has been postulated that the build up of raw humus and change of ion-exchange conditions would result in acidification. Importantly, one of the lakes began to acidify, before liming, under contemporary levels of acid deposition. -from Authors