Temporal and Spatial Variability of Soil pH in Patterned-Ground Chronosequences: Jotunheimen, Norway

Abstract

Glacier foregrounds of Jotunheimen, Norway are characterized by the occurrence of Little Ice Age end moraines, dating to approximately the mid 18th century. Patterned-ground features occurring within chronologically established time units were studied. Young patterned-ground features, forming ~ 10-20 years after deglaciation, are frost active with minimal soil development. With time and distance from the ice margin, frost activity declines within the patterned ground. Frost activity initially decreases at the borders of the features, with the centers later stabilizing. Sorted circles and sorted nets showed significant changes in soil pH across the chronosequences. Temporal thresholds were recognized on two of the chronosequences where patterned-ground features on terrain deglaciated ~ 1930 A.D. show increased acidification rates, suggesting a decline in frost activity and disturbance. Microsite variability was noted on one of the chronosequences with patterned-ground borders being more acidic than that of center positions. All glacier forelands showed a higher soil pH with depth in patterned-ground features. The importance of microsite variability and associated disturbance is stressed and should be incorporated when studying environmental change at traditional landscape scales.